Every ingredient amount is disclosed
The panel gives a per-ingredient amount rather than hiding quantities inside a proprietary blend, so each one can be compared to published research.
Full record · 740985225509 · back to the summary
21st Century Niacinamide 500 mg Prolonged Release Tablets
Exact product checkedGTIN 00740985225509 · checked 2026-07-25
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How to read this report
What this is. We compare what a listing claims against what public records show — label arithmetic, barcode registries, NIH’s label catalog, FDA enforcement data, certification registries, and published research. Every statement below traces to one of those.
What the states mean. Confirmed = an outside source agrees. Contradicted = an outside source disagrees. Caution = something needs explaining. No data = we looked and found nothing — a gap, not a strike.
What it is not. A clean record is not an endorsement and never proof a product works. A thin record is not an accusation. We publish evidence and gaps; the conclusion is yours. Nothing here is medical advice.
Something wrong? Every figure is meant to be checkable — sources are named and linked. Send a correction and we’ll fix the record.
Panel, decoded
What the label discloses
2listed rows
2separately quantified
0combined blend totals
The listing-image panel publishes an amount for each of its 2 listed rows. That supports ingredient-by-ingredient review; it does not verify the contents.
| Panel row | Amount | %DV | What to notice |
|---|---|---|---|
| Niacinamide | 500 mg | — | |
| Calcium (as Calcium Carbonate) | 160 mg | — |
FDA rules (21 CFR 101.36) require the amount of each dietary ingredient per serving unless hidden in a listed “proprietary blend” (legal, but a transparency yellow flag). A label stating no amount at all is non-compliant — a checkable red flag. This panel states amounts; the open question is whether those listed amounts are independently verified and how they compare with relevant research.
iHerb Supplement Facts (exact UPC/GTIN) Amounts are shown as listed panel data, not independently lab-tested contents.
Every check we ran
Confirmed evidence
What checked out2
These checks found support in the public record. They confirm specific facts, not the product as a whole.
Confirmed
Reviews accumulated gradually
Written reviews grew from 398 to 415 across 2026-03-27 – 2026-07-20 with no single manufactured spike (largest 30-day gain ~7).
Documented concerns
What needs caution0
These are documented contradictions or claims that need more evidence. They are separate from missing data.
No contradictions or product-specific cautions were found at this check depth.
Unresolved public record
What is still missing8
We looked for these signals but could not settle them from public sources. A gap is not a strike.
The listing doesn't publish enough to check the math
The saved listing evidence does not establish net weight, per-serving dose, servings per container, so the dose claim cannot yet be checked against serving arithmetic. This is a neutral evidence gap, not a pass or strike.
Multiple USPTO brand-owner records are shown
USPTO returned multiple live supplement-class records for the exact brand wordmark: Twenty-First Century Laboratories, Inc., Twenty-First Century HealthCare, Inc., Twenty First Century Nutritional Products, Inc.. These records answer who owns registrations for the brand; the separate product-to-owner or manufacturer link remains open.
Certified by NSF — contents and contaminants checked
21st Century HealthCare, Inc. appears in NSF’s certified-products registry with 0 certified product(s), but we couldn’t confirm this exact listing is among them. Certification covers contents and contaminants — not effectiveness.
FDA recall appears in this brand's history
Brand-level context only, not a finding about this product. Twenty-First Century Healthcare, Inc recalled a different or not-exactly-bound product on 2021-05-07: “A small quantity of bottles of Vitamin D3 125 mcg ((5000 IU) 100 ct. were mislabeled as Vitamin D3 25 mcg (1000 IU). Secondary labeling on the bottles (back label) is correctly labeled as Vitamin D3 125 mcg (5000 IU).” (status: Terminated). The recalled product was: “21st Century Vitamin D3 125 mcg (5000 IU) tablet, 100 count, UPC 7-40985-27431-6, 21st Century HealthCare, Inc., 2119 Wilson St., Tempe, AZ 85282” — not necessarily the product on this page. Verify at FDA’s recall database.
Public label filing not saved
This record does not currently hold an matched to this exact product public label filing for the exact product. That is a LookCloser coverage gap, not evidence that no filing exists.
This item belongs to a catalog variation family
The paid catalog links this exact item to a parent listing. Review counts on public product pages may be shared across sizes, flavors, or other variants, so the count history is listing context — not evidence that reviewers received or tested this exact variant.
180-day review-count history is on file
Exact-listing history records written-review counts from 396 on 2026-02-27 to 415 on 2026-07-20 (net +19). Count movements can reflect sales, listing variants, collection resets, or moderation; this history does not establish whether reviews are authentic.
UPC valid, no independent record
Check digit passes; no third-party database record found yet. Coverage gaps are common — not a strike.
What to ask and check
What would settle the open questions
Why is this shown?
Everything we couldn’t verify is something a person can still ask about. Rather than leave gaps sitting as dead ends, we turn each one into a specific question — the exact document, citation, or number that would settle it — plus the things you can confirm yourself with the bottle in your hand.
Ask the brand or seller
1
Can you send a clear photo of the full Supplement Facts panel?
It’s the one part of the label required to state what’s inside and how much. A seller who won’t show it before purchase is asking for trust the label would have earned.
2
Is this label filed with NIH’s Dietary Supplement Label Database (DSLD)?
Filing is voluntary, so absence proves nothing — but a filed label puts the full ingredient table on public record where anyone can read it.
Most brands and sellers publish a contact route. A clear answer adds evidence to the record; no answer leaves the question open.
Check for yourself — no one’s permission needed
1
Scan the barcode on the package and confirm it reads 740985225509.
A mismatch between the barcode on the box and the one on the listing is worth pausing over — it can indicate a different variant, a repack, or a counterfeit.
2
Look the product up yourself in NSF’s certified-products registry.
Search “21st Century HealthCare, Inc.” at info.nsf.org — certification covers contents and contaminants, not effectiveness.
3
Check the lot number and expiry on the bottle against any COA you’re given.
A certificate that doesn’t name your lot doesn’t describe what you’re holding.
These are the open questions on this specific record — not a warning about the product, and not a suggestion to buy or avoid it. Getting them answered is how you decide for yourself.
What the listing promises — claim by claim
Why is this shown?
A listing’s promises are the reason people buy. Each one gets its own row: what was promised, what evidence would settle it, and what we could actually find. We never call a claim false — only whether proof proportionate to it exists on the public record.
| Claim | Status | What we found |
|---|---|---|
| Manufacturing claim “…ide Absorption* Good For You TRUSTED QUALITY GMP Certified & FDA Registered” | Partly supported We looked for: the facility registration or certificate behind the claim | “GMP-certified” describes factory processes, not what is in the bottle. The claim does not name a certifier or public register that a shopper can check. |
| Benefit claim “…ease. PROLONGED RELEASE Energy & Circulatory Support* VITAMIN SUPPLEMENT GLUTEN FREE NON-GMO Prof…” | Not checked yet We looked for: whether the ingredient doses on the label match the doses used in published research | Ingredient-level evidence for this formula isn’t in our knowledge base yet. Recorded as not checked yet — not as a negative. |
“No evidence located” does not mean a claim is false — it means the seller has not put evidence proportionate to the claim on the public record, and we could not find any. Absence of proof is not proof of absence.
Verifiability profile — 2 of 6 public signals
✓ UPC / GTIN published✓ Brand's own store found· Per-serving dose established — not published· Supplement Facts visible in photos — not published· Found in NIH's label catalog (DSLD) — not published· Third-party lab named or registry-certified — not published
What this listing gives the public to check. Publishing these signals doesn't prove quality — but withholding them means claims can only be taken on faith.
Identity
| UPC (barcode) — also our record ID | 740985225509 — via source listing UPC |
| Brand | 21st Century |
| Source listing identifier | B004SCKMQS |
| Retailer listing title | 21st Century Niacinamide 500 mg Prolonged Release Tablets, 110 Count… show full title21st Century Niacinamide 500 mg Prolonged Release Tablets, 110 Count |
| USPTO brand-owner record | Twenty-First Century Laboratories, Inc. · ARIZONA, USA · registration 3645342 · 2119 South Wilson Street, Tempe, ARIZONA 85282, UNITED STATES |
| USPTO brand-owner record | Twenty-First Century HealthCare, Inc. · ARIZONA, USA · registration 4085491 · 443 West Alameda Drive, Tempe, ARIZONA 85282, UNITED STATES |
| USPTO brand-owner record | Twenty First Century Nutritional Products, Inc. · ARIZONA, USA · registration 1790110 · 2445 West 12th Street, Tempe, ARIZONA 85281, UNITED STATES |
From the label (photo-read)
| Serving size | one (1) tablet |
| Pack statement | 110 TABLETS |
| Badges printed on pack | GMP Certified & FDA Registered |
No Supplement Facts panel appears in the listing photos — the full per-ingredient table isn't shown to buyers before purchase. Recorded as a transparency gap, not a strike.
Claims printed on the packaging:
“PROLONGED RELEASE” · “Energy & Circulatory Support*” · “VITAMIN SUPPLEMENT” · “GLUTEN FREE” · “NON-GMO” · “Professionals Managing Demanding Work Schedules” · “Fitness Enthusiasts Supporting Their Workout Performance*” · “Adults Over 50 Who May Have Decreased Niacinamide Absorption*”
Read by a vision model from 7 listing photos — verbatim extraction; OCR errors possible. Spot a mistake? It will be corrected on review.
Where it sells
| Seller | Price |
|---|---|
| Retailer listing ↗ | $5.49 checked Jul 25, 2026 — varies by variant/session; price history pending |
Reference links for identification only — LookCloser has no affiliate relationships and earns nothing from any link on this page.
Ingredient science
No knowledge-base entry yet for this formula's active ingredients — entries are added as the KB grows. Absence of a science card is a coverage gap, not a judgment.
Record 740985225509 · built July 25, 2026 · lookcloser.ai · corrections@lookcloser.ai