Thursday, 06 August 2026 09:55 PM
Advertorial
As adults over 40 look for new ways to support energy, circulation, and active aging in 2026, this CircO2 review explores the brand-stated nitric oxide formula, dissolving lozenge delivery, 420 mg proprietary blend, customer feedback, pricing, and 90-day guarantee details buyers are checking before ordering.
NORCROSS, GA / ACCESS Newswire / August 6, 2026 / Quick disclosure before you read further: this is a paid advertorial, and a commission may be earned if you buy through links here. Product claims come from the brand, not independent testing. CircO2 is a dietary supplement - not a drug, not FDA-approved, and not intended to diagnose, treat, cure, or prevent any disease. Official site: advancedbionutritionals.com. This reflects brand materials reviewed in August 2026, so confirm current details before ordering. This content is promotional in nature and is intended for consumer education regarding a commercially available product.
CircO2 Reviews and Complaints: Circulation-Conscious Adults Discover the 4-Ingredient Nitric Oxide Blend Behind the Lozenge (Consumer Research)
You saw an ad for CircO2 - Advanced Bionutritionals' nitric oxide and circulation support lozenge, made for adults over 40 who want more energy and better blood flow as nitric oxide production naturally slows with age. Maybe it was on Facebook, maybe a YouTube pre-roll, maybe a friend mentioned it. Something about "Superhuman at 70" or the nitric oxide pitch caught your attention, and now you're doing exactly what smart buyers do before spending money: checking the details first.
Good move - because this isn't a first look at CircO2, it's an update. Here's what's different. Two prices for the same product, depending on which link brought you here. Two guarantees, with two different names, on the same sales page. A company name on the paperwork that doesn't match the one on its own Better Business Bureau listing. And a spokesperson swap this article hasn't seen mentioned anywhere else. All four, sourced and explained, below.
→ See CircO2 pricing and the guarantee that covers your order
What Is CircO2 and Who Is It For?
The brand positions CircO2 around nitric oxide (NO), which it describes as a signaling molecule involved in relaxing and widening blood vessels, supporting circulation and oxygen delivery. Advanced Bionutritionals markets CircO2 primarily to adults 40 and older whose nitric oxide production it says has slowed with age, and who are looking for support with energy, circulation, and general cardiovascular wellness rather than treatment of a diagnosed condition. This article has not independently verified a finished-product clinical effect for CircO2 specifically.
Specifically, the brand's marketing points to a cluster of frustrations it says trace back to declining nitric oxide: afternoon energy crashes, blood pressure numbers your doctor keeps flagging, memory lapses that used to be rare, joint stiffness that slows you down, and cold hands and feet that never used to be an issue. If a couple of those sound familiar, that's who the brand is talking to. This article hasn't independently verified that CircO2 resolves any of them - that's the brand's positioning, not a confirmed outcome.
Unlike a capsule or powder, CircO2 is a lozenge that dissolves on the tongue. The brand's positioning is consistent across its own product page and its sales presentation: this is a delivery-format differentiator, not a different product category. Every source reviewed for this article - the official product page, the sales presentation, and third-party retail listings - agrees CircO2 is marketed as a nitric oxide/circulation-support dietary supplement. No category conflict was found.
CircO2 is not positioned by the brand as a treatment for diagnosed cardiovascular disease. It carries the standard FDA disclaimer common to dietary supplements: these statements have not been evaluated by the Food and Drug Administration, and the product is not intended to diagnose, treat, cure, or prevent any disease.
Buyer Takeaway: Every source reviewed agrees on what CircO2 is - a nitric oxide/circulation supplement, not a different product category - so there's no positioning conflict to sort through here.
What Does CircO2 Actually Do?
Per the brand's sales materials, CircO2's approach centers on supporting the endothelium - the thin layer of cells lining blood vessels that produces nitric oxide. The brand states that as the endothelium's function declines with age, so does natural nitric oxide production, and CircO2's formula is positioned to support that pathway rather than simply flood the body with a single precursor compound.
The brand specifically markets CircO2 as taking a different approach than older-generation nitric oxide supplements built around L-arginine alone, stating that L-arginine supplementation "doesn't do much" for nitric oxide production in adults over 40. That is a brand claim, not an independently verified comparative finding, and it's presented here as brand-attributed positioning rather than this article's own conclusion.
According to the brand, CircO2's lozenge format is intended to let ingredients begin converting to nitric oxide as the tablet dissolves in the mouth, rather than requiring full digestion first. Individual results from any supplement vary by person, and the brand's own product pages state as much in their standard results-disclaimer language.
Buyer Takeaway: The endothelium-support framing is the brand's mechanism story, not a claim this article independently validates - the ingredient section below covers what's actually confirmed.
CircO2 Ingredients: What the Brand Pages Show
CircO2's Supplement Facts panel - confirmed directly from the brand's current sales page - separately quantifies three nutrients before listing a proprietary blend. (Quick note before the numbers: B12's Daily Value percentage below looks unusually high, but that's normal for B12 specifically - its official reference intake is tiny, so even a standard dose shows a large percentage. It's not a labeling error.)
Vitamin C: 100 mg, 111% Daily Value (as magnesium ascorbate and ascorbic acid)
Vitamin B12: 1,000 mcg, 41,667% Daily Value (as methylcobalamin)
Magnesium: 4 mg, 1% Daily Value (as magnesium ascorbate)
Proprietary Nitric Oxide Blend: 420 mg total (Daily Value not established) - beet root powder, hawthorn berry extract, L-citrulline, and sodium nitrite
Other (non-active) ingredients per the brand's current label: mannitol, xylitol, modified cellulose, microcrystalline cellulose, plant-based magnesium stearate, natural flavor and color, silica, and stevia leaf extract.
Serving size is confirmed as 1 tablet, with 30 servings per container.
Here's the transparency gap worth naming directly: the total weight of the Proprietary Nitric Oxide Blend (420 mg) is confirmed, and so are the four ingredients inside it. What's not disclosed on the pages reviewed is how that 420 mg splits across beet root powder, hawthorn berry extract, L-citrulline, and sodium nitrite individually. That's common with "proprietary blend" labeling generally, and it isn't unique to CircO2. It does mean a reader can't independently verify whether any single ingredient in the blend is present at a dose that matches published research on that ingredient.
If the individual per-ingredient breakdown matters to your decision, chase it down before you buy. For a nitric oxide supplement, dose often matters more than ingredient presence alone. The most direct path is to contact Advanced Bionutritionals' customer service line at 800-791-3395 and ask for the full quantitative breakdown of the blend, or to request a label photo before ordering.
Buyer Takeaway: Vitamin C, B12, and magnesium doses are confirmed (or at least itemized); the 420 mg nitric-oxide blend's four ingredients aren't broken out individually - call before you order if that gap matters to you.
→ Check the CircO2 ingredient list and current offer
What the Research Says About Nitric Oxide and Circulation
The ingredients in CircO2's blend are individually discussed in the general nitric-oxide and circulation research literature, and the brand's marketing draws on that literature. Beet root and other nitrate-rich foods have been studied in relation to nitric oxide levels and exercise performance. L-citrulline is studied as a precursor the body converts toward nitric oxide production. Hawthorn has a long history of traditional cardiovascular use and has been studied for effects on blood vessel function and blood pressure. This article has not independently reviewed or verified the specific studies behind these ingredient categories, and is not citing named trials, doses, or outcomes - treat this as a description of the general research area the brand's marketing invokes, not a scientific endorsement.
That research addresses these ingredients generally - not CircO2 as a finished, combined product at its specific (and partly undisclosed) blend amounts. This article has not independently evaluated whether the cited research used the same ingredient forms, amounts, population, or duration as CircO2's formula, and ingredient-level research should not be treated as evidence that CircO2 itself produces the same outcomes. No clinical trial of the finished CircO2 formula was located in the materials reviewed for this article. For a deeper look at the brand's stated nitric-oxide mechanism and its suggested 3-, 6-, and 12-month usage timelines, see earlier coverage of how CircO2's nitric oxide mechanism is positioned to affect circulation, energy, and memory.
One caution does come directly from the brand's own sales materials rather than general research: the brand states that because CircO2 works by relaxing blood vessels and improving blood flow, people with low blood pressure should consult a physician before taking it. That's a brand-stated caution, not this article's independent medical advice, but it deserves to be taken seriously since it comes from the product's own marketing.
Buyer Takeaway: The ingredients have been discussed in ingredient-level research, but this article hasn't independently evaluated the applicable studies, doses, or outcomes - and that's not the same as a clinical trial of CircO2 itself, which hasn't been located.
How to Use CircO2: Dosage and Directions
The Supplement Facts serving size is one tablet, dissolved on the tongue rather than swallowed. But that's not the brand's complete usage guidance. The brand's own FAQ material suggests starting with CircO2 twice a day for the first week or two, then switching to once daily once you've gotten a sense of how it affects you. A 30-tablet box works out to a full month at once-daily use, but closer to two weeks if you follow the twice-daily introductory period. As with any supplement, check with your doctor before starting CircO2, and don't exceed the label or brand directions on your own, especially if you take prescription medication or have an existing cardiovascular condition.
Buyer Takeaway: Don't assume "one box = one month" until you know which usage pattern you're following - the brand's own suggested start is twice a day, not once.
Shipping and Delivery
Per the brand's Shipping and Returns page:
Domestic (U.S.) orders: ship within 1-2 business days after processing, with delivery in 3-5 business days from there
International orders: ship within the same 1-2 business day processing window, but take 7-14 business days to arrive, varying by destination and customs processing
No expedited-shipping option or associated fee was disclosed on the pages reviewed for this article.
Buyer Takeaway: If you're ordering CircO2 from outside the U.S., budget for up to two weeks of transit time rather than assuming domestic-speed delivery.
Certifications and Manufacturing
Per the brand's own Quality page, CircO2's manufacturing claims include:
GMP (Good Manufacturing Practices) certified facility, per the brand's own statement
Batches tested against a purity index using FTIR spectrometers
Disintegration-tested according to USP guidelines
"Manufactured in the USA from globally sourced ingredients" - a qualified Made-in-USA claim, meaning the finished product is assembled domestically while some raw ingredient inputs may originate outside the U.S.
No independent registry confirmation of GMP certification status was located outside the brand's own claims for this article.
Buyer Takeaway: The GMP and USP claims come directly from the brand's own page, not an independent certifying body's public registry - treat them as brand-stated until you've confirmed otherwise.
CircO2 vs. L-Arginine Nitric Oxide Supplements
The brand positions CircO2 as an alternative to the older generation of nitric oxide supplements built around L-arginine, stating that L-arginine supplementation is "nearly useless" for boosting nitric oxide in adults over 40 due to how the body absorbs and metabolizes it with age. CircO2 instead leans on L-citrulline (an L-arginine precursor with different absorption characteristics), dietary nitrate from beet root, and sodium nitrite as its nitric-oxide pathway ingredients. This is the brand's own comparative claim and is presented here as brand-attributed positioning, not an independently verified head-to-head finding - this article did not locate a third-party comparative study of CircO2 specifically against an L-arginine-only formula.
Buyer Takeaway: If you've tried an L-arginine supplement before without noticeable results, CircO2's different-pathway approach is the brand's stated rationale for why - but that rationale comes from the brand, not an independent comparison.
CircO2's New Spokesperson: Who Is Dr. Greg Eckel?
The brand's current sales page names Dr. Greg Eckel, a naturopathic physician, as CircO2's endorser, and discloses directly that he is compensated by Advanced Bionutritionals for that endorsement. Unlike some supplement spokespersons, Dr. Eckel's identity and credentials are independently verifiable. Public records confirm:
Licensed naturopathic physician (ND) and licensed acupuncturist
Founder of the bVital clinic in Park City, Utah
Past president of the Oregon Board of Naturopathic Medical Examiners
Author of a published book on integrative approaches to Parkinson's disease
Has appeared on several national broadcast networks
One thing worth naming plainly: Dr. Eckel's own published clinical focus, based on his professional bio and public materials, centers on brain regeneration and neurodegenerative conditions like Parkinson's disease - not cardiovascular health or nitric oxide supplementation specifically. That doesn't mean his endorsement is invalid, but it's a different specialty than the product category he's endorsing, and readers should know that going in.
One more detail: earlier brand-published coverage of CircO2 named a different physician, Dr. Frank Shallenberger, as the product's compensated endorser. The current sales page names Dr. Eckel instead. This article did not find a stated reason for the change, and isn't speculating on one - just noting that the named endorser has changed since earlier coverage.
Buyer Takeaway: Dr. Eckel is a real, credentialed physician being paid to endorse this product - both facts are independently confirmable. His primary published expertise is brain regeneration, not cardiovascular medicine, and he's not the same endorser named in earlier CircO2 marketing.
CircO2 Pricing: Which Price Will You Actually Pay?
CircO2's sales presentation (the page most buyers land on from marketing links, including the "Superhuman at 70" promotion referenced earlier) lists three package sizes, each as a one-time payment:
1 Box: $49.95, described as a sample/trial size with no free shipping
3 Boxes: $134.85 total, or $44.95 per box - brand-stated savings of $15 off the per-box rate, with free shipping
6 Boxes: $249.00 total, or $41.50 per box - brand-stated savings around $50.70, with free shipping
Worth knowing: Advanced Bionutritionals also operates its own shopping-cart product page for CircO2, separate from the sales presentation above, and it shows different figures - $59.95 for one box, $159.90 ($53.30/box) for three, and $249.00 ($41.50/box) for six. The six-box price converges across both; the one-box and three-box prices don't. This isn't necessarily a red flag - different marketing funnels for the same product commonly carry different offers - but it means the price you're quoted can depend on which link brought you to checkout. Compare what's actually shown on your checkout page against both sets of figures here before you enter payment information.
Any "regular price," "instant savings," or reference-price figures shown on either page are the brand's own stated marketing numbers, not an independently verified benchmark - treat them as brand-asserted, not a third-party price comparison. Prices, package structure, and any active codes can change without notice; confirm current pricing directly at checkout before ordering. Check before you click buy.
The brand's site also notes that CircO2 purchases may be eligible for HSA/FSA reimbursement through a third-party service (Truemed). This is described as a post-purchase process: you complete your order, fill out a qualification form, and - if approved - receive a Letter of Medical Necessity to submit to your HSA/FSA provider. This is explicitly conditional ("may be able to," "tax savings vary" per the brand's own disclosure) rather than a guarantee of eligibility or reimbursement, and this article does not represent insurance coverage or HSA/FSA eligibility as confirmed or guaranteed for any individual buyer. Nothing here is a promise.
Buyer Takeaway: The six-box tier brings the per-box price down from $49.95 to $41.50 - a real but modest reduction, not a dramatic one. Larger packages mean more upfront spend either way.
→ See which of CircO2's two prices applies to your order
CircO2 Reviews: What Buyers Are Saying
The brand's own product page displays a review widget showing 1,618 customer reviews, a 3.9 out of 5 average rating, and 74% of reviewers indicating they'd recommend the product. This is brand-hosted feedback displayed on the brand's own site - not data from an independent third-party review platform, and this article does not independently audit or verify the accuracy of that count, average, or recommendation percentage.
The brand's own Terms of Use state that testimonials and reviews featured in its marketing "are exceptional results from our most successful users." They "do not represent the generally expected user experience." That's the brand's own typicality disclosure - read it before weighing any individual review heavily in your decision.
Buyer Takeaway: A 3.9/5 average across 1,618 brand-hosted reviews is a mixed-to-positive signal, not a rave - read a range of reviews rather than just the featured ones.
CircO2's Guarantee: Which One Actually Applies to You?
CircO2's sales presentation advertises what it calls a "Down to the Last Lozenge" guarantee: you can return the product within 90 days of your purchase - even if the box is completely empty - for a full refund. That's a stronger promise than a typical unopened-product-only return policy, and it's a distinction that matters, since it's not the same guarantee described on the brand's general Shipping and Returns page, which gives standard instructions built around unopened bottles.
Here's a detail that matters: the brand's sales page actually names two separate guarantee programs. The "Down to the Last Lozenge" guarantee is CircO2-specific and explicitly covers empty boxes, while a second, more general "ABN™ 100% Satisfaction Guarantee" appears on the same page without spelling out whether an emptied box qualifies. Both are stated as 90 days from purchase, so there's no length conflict - but if you're relying on the empty-box provision specifically, confirm with customer service that it applies to your order, since it's the CircO2-specific guarantee that makes that promise explicit, not the general one.
Per the brand's Terms, here's how the refund itself works:
Return shipping: buyer's responsibility, unless the return is due to an error on the brand's part
Return address: Advanced Bionutritionals, P.O. Box 8051, Norcross, GA 30091
Refund amount: full purchase price for approved returns, issued to your original payment method
Processing timeline (per the Terms of Use): roughly 1-2 business days after the return is received, plus up to 10 additional days for the refund to post to your account
Processing timeline (per the separate Shipping and Returns page): "within 7-10 business days" of receipt
Both timelines land in a similar overall range, but they aren't worded identically - which matters if you're timing a return around a statement cycle.
If you'd rather buy again after already using the guarantee once, note the brand's Terms specify that a repeat purchase after a refunded order does not carry a renewed guarantee eligibility for that same product.
Buyer Takeaway: Two guarantee names, same 90-day window - if the empty-box provision matters to you, confirm it's the CircO2-specific guarantee applying to your order, not just the general one.
Is CircO2 Right for You?
CircO2 may be worth considering if:
You're an adult over 40 looking for a lozenge-format nitric oxide supplement
You're comfortable with a proprietary-blend label that doesn't break out every individual ingredient dose
A 90-day return window matters to you as a safety net
CircO2 may not be the right fit if:
Per-ingredient dosing transparency is a hard requirement for you - the accessible pages don't provide it for most of the blend
You're currently on blood-pressure medication or another cardiovascular prescription and haven't yet cleared a nitrate/nitric-oxide-focused supplement with your prescriber
You were expecting a capsule or powder format rather than a dissolving lozenge
Buyer Takeaway: The lozenge format and proprietary-blend labeling are the two biggest things to be comfortable with before ordering - everything else about CircO2 is fairly standard for the category.
→ Verify current CircO2 details before checkout
Things to Verify Before You Order
Verify #1 - Corporate entity name. The brand's current Terms of Use identify the website owner as Advanced Bionutritionals, LLC, at 5305 Oakbrook Parkway, Norcross, GA 30093. A Better Business Bureau accreditation seal displayed on the same pages is linked to a differently named business record: "Soundview Communication, Inc., Publishers Periodical, Norcross, GA." This article does not speculate on why. Buyers who need the precise merchant or billing entity should review the name shown on their final checkout page and order confirmation. Call customer service to ask directly if it matters for a billing dispute, arbitration correspondence, or BBB inquiry.
Verify #2 - Per-ingredient blend amounts. CircO2's label separately confirms vitamin C (100 mg), vitamin B12 (1,000 mcg), magnesium (4 mg), and a 420 mg Proprietary Nitric Oxide Blend of beet root powder, hawthorn berry extract, L-citrulline, and sodium nitrite. The blend's total weight is confirmed; the individual amounts of its four ingredients are not. If dosing precision matters to you, request the full breakdown from customer service (800-791-3395) before ordering.
Verify #3 - Refund processing timeline wording. The brand's Terms of Use and its separate Shipping and Returns page describe the refund-processing window slightly differently (1-2 business days to process per the Terms vs. "within 7-10 business days" per the Returns page). Both land in a similar overall range, but if you're tracking a refund against a billing cycle, ask customer service which timeline applies to your specific order.
Verify #4 - Subscription status. On the brand's own shopping-cart product page, all three CircO2 package tiers were shown as one-time payments. This article did not access or observe the checkout screen on the sales-presentation funnel directly, and the brand's site-wide Terms of Use separately describe a general auto-shipment subscription program that may apply to some purchase paths. If you want to be certain you are not enrolled in recurring billing, confirm at checkout - whichever page you're ordering from - and review your order confirmation email before submitting payment.
Verify #5 - Endorsing physician. The brand's current sales page names Dr. Greg Eckel as CircO2's compensated endorser; earlier brand-published coverage named a different physician, Dr. Frank Shallenberger. Both appear to be real, credentialed practitioners - this article did not find evidence suggesting otherwise - but if the specific endorser's background factors into your decision, verify which one is current before you order, since brand marketing pages can lag behind changes like this.
Buyer Takeaway: None of these four items are red flags on their own - they're just the specific things this article couldn't fully confirm from accessible pages, so verify them directly before you check out.
CircO2 Complaints: What the Available Reviews Show
This article did not review a systematic or independently audited complaint dataset for CircO2 - no dedicated complaint-tracking source, like a BBB complaint log, was located. Earlier brand-published coverage of CircO2's ingredient breakdown, pros and cons, and legitimacy questions described two recurring themes. Treat this as one source's characterization rather than a verified pattern: taste and dissolve-time (since CircO2 is a lozenge rather than a capsule, some reviewers reportedly find the flavor strong or the dissolve time slow), and occasional difficulty reaching customer service or delays in refund processing. This article did not independently verify the frequency, current accuracy, or representativeness of either theme. That earlier coverage also named Dr. Frank Shallenberger - not Dr. Eckel - as the product's endorsing physician at the time, consistent with the spokesperson change noted above.
The brand-hosted rating on CircO2's own product page (1,618 reviews, 3.9/5 average) should not be treated as an independently audited complaint record either - it's brand-hosted feedback, not a third-party-verified dataset. If service responsiveness matters to your decision, the most reliable way to check is a pre-purchase call to 800-791-3395 before you order a larger package.
Buyer Takeaway: No independently verified complaint pattern exists for CircO2 in the sources available to this article - treat any single review site's "common complaints" framing, including earlier brand-published coverage, as anecdotal rather than data.
CircO2 Side Effects and Safety Considerations
No brand-published list of specific side effects for CircO2 was located. The one safety caution that does come directly from the brand's own sales materials: because the product is intended to relax blood vessels and improve blood flow, people with low blood pressure are advised to consult a physician before taking it.
Beyond that brand-stated caution, talk to a doctor or pharmacist before starting CircO2 if:
You take prescription medication, especially blood pressure medication or nitrates
You are pregnant or nursing
You have a diagnosed medical condition, particularly a cardiovascular one
This article is not a substitute for that conversation.
Fast Facts
Brand: Advanced Bionutritionals, LLC
Product: CircO2® - nitric oxide / circulation support lozenge
Format: Dissolving tablet/lozenge, not a swallowed capsule
Serving size: 1 tablet; 30 servings per container
Separately quantified nutrients: Vitamin C (100 mg, 111% DV), Vitamin B12 (1,000 mcg, 41,667% DV), Magnesium (4 mg, 1% DV)
Proprietary Nitric Oxide Blend: 420 mg total - beet root powder, hawthorn berry extract, L-citrulline, sodium nitrite (individual amounts not disclosed)
Sales-presentation pricing: 1 Box $49.95 / 3 Boxes $134.85 ($44.95/box) / 6 Boxes $249.00 ($41.50/box)
Brand's separate shopping-cart pricing differs: 1 Box $59.95 / 3 Boxes $159.90 ($53.30/box) / 6 Boxes $249.00 ($41.50/box)
Guarantee: "Down to the Last Lozenge," 90 days from purchase, empty box eligible - a separate general "ABN Satisfaction Guarantee" also appears on the sales page at the same 90-day window
Buyer pays return shipping; returns to P.O. Box 8051, Norcross, GA 30091
Customer service: 800-791-3395
Directions: brand FAQ suggests twice-daily use for the first 1-2 weeks, then once daily
Manufacturing: Brand states "manufactured in the USA from globally sourced ingredients"
Certifications disclosed: GMP-certified manufacturing facility; USP-guideline disintegration testing (brand-stated)
On-page reviews: 1,618 reviews; 3.9/5 average; 74% recommend (brand-hosted, not third-party-audited)
Corporate entity note: ToS names Advanced Bionutritionals, LLC; BBB seal on the same site names Soundview Communication, Inc.
Quick Answers
Is CircO2 legit or a scam?
CircO2 is currently marketed through Advanced Bionutritionals sales pages that publish package pricing, published customer-service phone numbers, a stated 90-day guarantee, and brand-hosted customer reviews. That doesn't independently verify product efficacy or every marketing claim made about it, and this article isn't in a position to certify the product one way or the other. The verification steps in this article - particularly around pricing and the corporate-entity naming detail - are worth working through before you order.
What does CircO2 actually contain?
Separately quantified vitamin C (100 mg), vitamin B12 (1,000 mcg), and magnesium (4 mg), plus a 420 mg Proprietary Nitric Oxide Blend of beet root powder, hawthorn berry extract, L-citrulline, and sodium nitrite. The blend's total weight is confirmed; how it splits across those four ingredients is not.
How much does CircO2 cost?
The sales presentation lists $49.95 for one box, $134.85 for three boxes ($44.95 each), or $249.00 for six boxes ($41.50 each). The brand's separate shopping-cart page shows different one-box and three-box pricing ($59.95 and $159.90) - check which figures apply to your specific checkout link before ordering.
Can I return CircO2 if it doesn't work for me?
Yes - the sales page advertises a 90-day "Down to the Last Lozenge" guarantee that covers even an empty box. You pay return shipping, and the brand refunds your purchase price once your return is received and processed. Confirm the exact window and process with customer service before mailing anything back.
→ View current CircO2 offer details
Frequently Asked Questions
Who makes CircO2?
CircO2 is manufactured and sold by Advanced Bionutritionals, LLC, a Norcross, Georgia-based nutraceutical company, per the brand's own Terms of Use and site footer. A Better Business Bureau accreditation seal displayed on the same pages lists a differently named business, Soundview Communication, Inc.; this article documents both names rather than resolving the discrepancy on the brand's behalf. No FDA clearance, approval, or authorization was confirmed in the materials reviewed, and this article does not independently classify the product under FDA medical-device regulations.
What is the main ingredient in CircO2?
CircO2's Supplement Facts panel separately lists vitamin C (100 mg), vitamin B12 (1,000 mcg), and magnesium (4 mg), before a 420 mg Proprietary Nitric Oxide Blend of beet root powder, hawthorn berry extract, L-citrulline, and sodium nitrite. Beet root powder and L-citrulline are both commonly cited nitric-oxide-pathway ingredients in the broader supplement category, but the brand's accessible pages don't disclose which of the four blend ingredients makes up the largest share of that 420 mg by weight. All three individual nutrients and the blend's total weight are confirmed; the blend's internal breakdown isn't.
Does CircO2 contain L-arginine?
No. The brand specifically markets CircO2 as an alternative to L-arginine-based nitric oxide supplements, stating that L-arginine supplementation is less effective for nitric oxide production in adults over 40 - a brand claim presented here as brand-attributed positioning, not an independently verified comparative finding. Instead, the formula relies on L-citrulline, dietary nitrate from beet root, and sodium nitrite as its nitric-oxide pathway ingredients, per the brand's own materials. This is a formulation choice, not a claim that L-arginine is unsafe.
Is CircO2 vegan, gluten-free, or allergen-free?
The official product page reviewed for this article did not provide a complete vegan or allergen-free certification statement. Third-party retail listings bearing the brand name describe the product as non-GMO, gluten-free, dairy-free, soy-free, and vegan, with no artificial preservatives - consistent with, though not identical to, the "no artificial... fillers, or preservatives" language on the brand's own Quality page. Consumers with diagnosed allergies or dietary restrictions should confirm current allergen status directly with the manufacturer rather than relying on retail-listing claims alone.
How long does one box of CircO2 last?
Each box contains 30 tablets. At the labeled serving size of one tablet daily, that's roughly a 30-day supply. But the brand's own FAQ material suggests starting with two tablets a day for the first week or two before dropping to one - at that pace, a box lasts closer to two weeks initially. Supply duration depends entirely on which usage pattern you follow, so don't assume "one box, one month" without checking the brand's current directions.
Where is CircO2 manufactured?
The brand states its products, including CircO2, are "manufactured in the USA from globally sourced ingredients" - a qualified Made-in-USA claim under FTC guidance, meaning the finished product is made domestically while some ingredient inputs may be sourced internationally. The brand also states its manufacturing facility is GMP-certified and that batches undergo USP-guideline disintegration testing, per its own Quality page. None of these certification claims were independently verified against a third-party registry for this article; they're presented here as the brand's own stated quality-control process.
Does CircO2 have side effects?
This article did not locate a brand-published list of specific side effects for CircO2. The brand's own sales materials do include one specific caution: because the formula is intended to relax blood vessels and improve blood flow, people with low blood pressure are advised to consult a physician before taking it. More broadly, talk to a doctor or pharmacist first if you take prescription medication, are pregnant or nursing, or have a diagnosed medical condition - standard precautions for this category of supplement, not something specific to CircO2. The brand's Terms of Use also note that individual results and experiences can vary from person to person.
Is CircO2 available on Amazon?
A listing bearing the Advanced Bionutritionals brand name and matching this product's ingredient profile was located on Amazon. Pricing, package size, and current availability on any third-party retail platform can differ from the brand's own sites and should be checked independently - this article's pricing figures reflect the brand's own pages, not the Amazon listing. The Amazon listing was used in this article only to help cross-check ingredient details, not as a pricing source. If you do buy through a third-party platform, confirm you're getting the current formulation and that the listing is sold or fulfilled by the actual brand.
Is CircO2 sold at Walmart?
A CircO2-branded listing was located on Walmart.com at the time of this review, separate from the brand's own site. As with any third-party marketplace listing, this article did not verify whether that listing is operated by Advanced Bionutritionals directly or by an unaffiliated third-party seller, and marketplace pricing, formulation, and guarantee eligibility can differ from what's confirmed on the brand's own pages in this article. If the 90-day guarantee matters to your decision, ordering directly from the brand is the more reliable path to qualifying for it.
Does CircO2 require a subscription?
Not on the brand's own shopping-cart product page - all three CircO2 package tiers there were listed as one-time payments. This article did not directly observe the checkout screen on the sales-presentation funnel. The brand's site-wide Terms of Use separately describe a general auto-shipment subscription program that may apply to some purchase paths; if enrolled in that program, cancellation requires contacting the brand at least 72 hours before the next scheduled shipment by phone (800-791-3395) or email. Your order confirmation email is the fastest way to check whether a one-time or recurring charge applies to your specific purchase.
How do I contact Advanced Bionutritionals about CircO2?
For general customer service, call 800-791-3395. For shipping, delivery, or return questions specifically, call 800-613-5721 (toll-free) or 678-987-5891 (local), or fax 770-399-0815. Mail correspondence and returns go to P.O. Box 8051, Norcross, GA 30091. The company's headquarters address is 5305 Oakbrook Parkway, Norcross, GA 30093. Customer service hours are 8am-7pm CST Monday-Friday and 8am-5pm CST Saturday, per the brand's Terms of Use. Have your order number ready before you call. It speeds things up considerably.
Is there a CircO2 lawsuit?
This article did not locate any lawsuit, FTC enforcement action, or class-action filing involving CircO2 or Advanced Bionutritionals in the materials reviewed. That's not the same as an exhaustive legal-records search, and this article does not represent it as one. If litigation history factors into your decision, a search of federal and state court records (such as PACER or your state's court database) would be the more authoritative source than this article or any other review site.
Is CircO2 FDA-approved?
No. Like all dietary supplements, CircO2 does not require FDA approval to be sold, and no FDA clearance, approval, or authorization was confirmed in the materials reviewed for this article. The brand's own product page includes the standard disclaimer that its statements have not been evaluated by the FDA and that the product is not intended to diagnose, treat, cure, or prevent any disease. This is standard, industry-wide language for dietary supplements, not something specific to CircO2.
What is CircO2's average customer rating?
The brand's own product page displays 1,618 customer reviews averaging 3.9 out of 5 stars, with 74% of reviewers indicating they would recommend the product. This is brand-hosted review data displayed on the brand's own site, not data independently verified by a third-party review platform, and the brand's Terms note that featured testimonials reflect its most successful users rather than a typical outcome. No independent, third-party-audited rating for CircO2 was located for this article. Read a range of reviews, not just the top ones.
Can I get a refund if I already opened the box?
Likely yes. The sales page's "Down to the Last Lozenge" guarantee specifically advertises that you can return the product within 90 days even if the box is completely empty. That's a different, more generous standard than the brand's general Shipping and Returns page. That page gives standard packing instructions built around "unopened bottles." Since the two pages describe different processes, call customer service at 800-791-3395 before you mail anything back, confirm which guarantee applies to your specific order, and get the current return instructions in writing.
Does CircO2 interact with blood pressure medication?
This article did not locate a brand-published drug-interaction list naming specific medications. The brand's own materials do say that because CircO2 is intended to relax blood vessels and improve blood flow, people with low blood pressure should consult a physician before taking it. That caution is brand-stated, not this article's independent medical guidance. If you take blood pressure medication, nitrates, or another cardiovascular prescription, talk to your prescribing physician or pharmacist before starting CircO2 rather than relying on this article for interaction guidance.
What's the difference between CircO2's 1-box, 3-box, and 6-box options besides price?
All three tiers contain the same product at the same per-tablet formulation - the difference is purchase quantity and per-unit price. On the sales presentation, the six-box tier brings the per-box price down from $49.95 to $41.50, a difference of $8.45 per box, not a dramatic discount. The brand's separate shopping-cart page shows a bigger per-box spread ($59.95 down to $41.50). Either way, a larger package means more upfront spend, not necessarily a better deal per dose - check both sets of figures against what your specific checkout shows.
Buyer Takeaway: Treat the checklist below as a five-minute pre-order routine, not a reason to hesitate - most of these steps are a single phone call or a careful read of your confirmation email.
→ Ready to order? Check current CircO2 availability
Buyer Verification Checklist
Confirm current CircO2 pricing and package options directly on the official checkout page, since prices and any active savings codes can change without notice.
Call 800-791-3395 and ask for the full per-ingredient milligram breakdown of the Proprietary Nitric Oxide Blend if dosing transparency matters to your decision.
If you're on blood pressure medication, a nitrate prescription, or have a diagnosed cardiovascular condition, clear CircO2 with your prescriber before ordering.
Note which corporate entity name appears on your order confirmation and credit card statement - Advanced Bionutritionals, LLC or another name - in case you need it for a future dispute or BBB inquiry.
Confirm at checkout that you are not being enrolled in a recurring auto-shipment subscription, and save your order confirmation email.
If you plan to use the 90-day guarantee, mark your purchase date on a calendar and keep your packing slip or order confirmation for the return.
If pursuing HSA/FSA reimbursement through Truemed, complete the qualification form promptly after purchase, since eligibility and tax savings are not guaranteed for every buyer.
The Bottom Line
CircO2 is a lozenge-format nitric oxide and circulation-support supplement marketed by Advanced Bionutritionals, currently sold through both a sales-presentation funnel and the brand's own shopping-cart page - and those two channels show different pricing for the same product. If you've read other CircO2 reviews online, most cover ingredients and benefits without touching this. The label separately confirms vitamin C (100 mg) and vitamin B12 (1,000 mcg), plus a 420 mg Proprietary Nitric Oxide Blend of four ingredients whose individual amounts aren't broken out. That's a transparency gap you can close with a phone call before you order, if per-ingredient dosing matters to you.
Pricing runs $49.95 to $249.00 depending on package size and which funnel you order through - compare both sets of figures against your actual checkout page before you pay. The "Down to the Last Lozenge" guarantee is a genuinely strong offer, explicitly covering empty boxes within 90 days. Just confirm at the time of your order that the CircO2-specific guarantee - not the site's general one - applies, since the two are named separately on the same page.
The corporate entity name on the brand's own Terms of Use (Advanced Bionutritionals, LLC) doesn't match the name tied to the BBB accreditation seal displayed on the same pages (Soundview Communication, Inc.). This article doesn't speculate on why. If you want clarity on exactly who you're contracting with, that's worth a direct call to customer service before you order - via the phone number and mailing address below.
Buyer Takeaway: CircO2 publishes real contact information, a stated guarantee, and brand-hosted reviews - none of which this article independently audits. The pricing discrepancy between funnels, the two-named-guarantees detail, and the entity-name mismatch are worth verifying directly before you commit to a larger package.
None of that makes CircO2 a bad choice - it makes it a normal one, with a few extra minutes of homework worth doing first. Strip away the discrepancies and what's left is a formula with a credentialed, publicly verifiable endorser, a 90-day guarantee that covers the product even once the box is empty, and a company that answers its phones and mails to a real address. For a lot of buyers, that combination is enough to feel good about placing an order, once the details above are squared away.
→ Get current CircO2 pricing and order details
CircO2 Contact Information
Customer Service: 800-791-3395 (toll-free)
Shipping & Order Fulfillment: 800-613-5721 (toll-free) / 678-987-5891 (local) / 770-399-0815 (fax)
Returns & Mail: Advanced Bionutritionals, P.O. Box 8051, Norcross, GA 30091
Corporate Headquarters: Advanced Bionutritionals, LLC, 5305 Oakbrook Parkway, Norcross, GA 30093
Official Site: advancedbionutritionals.com
→ Check current CircO2 pricing
Disclosure and Compliance Information
Material Limitations. This article is based on the CircO2 official product page, the brand's current sales presentation, Terms of Use, Shipping and Returns page, Contact Us page, and Quality page (live-fetched or directly reviewed in August 2026), prior brand-published coverage, and additional product documentation supplied for editorial review. No product testing was conducted by this publication. Brand claims are attributed to the brand and are not independently verified or endorsed. Title phrases in this article's headline are brand-originated marketing/positioning language, not this publication's independent findings. Facts that could not be confirmed from accessible sources have been omitted or explicitly flagged as unconfirmed rather than assumed. This includes the individual milligram breakdown of the four ingredients inside the 420 mg Proprietary Nitric Oxide Blend. It also includes a specific reason for the two different corporate entity names appearing across the brand's site, and a specific reason for the change in named spokesperson between earlier brand materials and the current sales page. Contact the brand directly to verify any material claim before purchasing.
Third-Party Feedback Platforms. The accuracy of third-party review platforms and brand-hosted review widgets referenced in this article is not endorsed. Evaluate all customer feedback critically, including its source and any disclosed selection criteria.
Forward-Looking Statements. This article reflects information available as of August 2026. Specifications, ingredients, pricing, package structure, and policies may change after publication. Rely on the brand's official site for current information before ordering.
Marketing Language Notice. Attribution language throughout this article identifies claims as brand-stated. Promotional phrases in this article's title and body are the brand's own marketing language, reflected here for verification context - not independent rankings, lab-verified claims, or this publication's endorsement.
California Proposition 65. This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. California buyers should verify the product label and any applicable Proposition 65 warnings published by the manufacturer before purchase.
Trademark Acknowledgment. CircO2® and Advanced Bionutritionals® are trademarks of Advanced Bionutritionals, LLC, used here descriptively to identify the product under review. No affiliation with or endorsement by the trademark holder is implied by this article's publication.
Geographic and Jurisdiction Notice. Shipping availability, pricing, and applicable regulations referenced in this article pertain primarily to U.S. buyers. International readers should confirm shipping eligibility, pricing in local currency, and local regulatory requirements directly with the brand before ordering.
SOURCE: Advanced Bionutritionals