“CERTIFIED”
Evidence →“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.
Exact product checked · GTIN 00850033272215Double Wood Supplements · checked Jul 24, 2026 · on sale since Jul 12, 2022🇺🇸 USPTO wordmark owner · Double Wood LLC · PENNSYLVANIA, USAPackage says manufactured for: Double Wood LLC · 3510 SCOTTS LN STE 219 PHILADELPHIA, PA 19129-1573 United States
Quick read · Double Wood Supplements
Magnesium Glycinate 400mg | 180 Capsules | Sleep
Checked against public sources between July 24 and September 1, 2026 · LookCloser does not sell or recommend supplements.
180capsules
180servings per container
Does the marketing hold up?
Testing claimed — documentation not found. The observed listing claims third-party testing without naming a lab or certifier. No product-bound report is saved, so the claim cannot be verified as stated. …
Is the dose real?Panel read — dose not verified2 ingredients listed; no advertised amount we could confirm against them
What a serving costs$0.09per serving, at the checked price
Is it tested?NSF seal printed on the labelwe read it off the package photo; not confirmed in NSF’s registry
Who’s behind it?🇺🇸Double Wood LLClimited liability company · PENNSYLVANIA, USA
Is it the real thing?✓Barcode matches outside records
Trouble on record?Recall check not run yeta gap in our records, not a finding about the product
“Couldn’t verify” means we looked and found no public proof — not a mark against the product. Most supplement claims cannot be independently verified by anyone, so grey is the normal state of this industry.
2◖ partly confirmed2? couldn’t verifyno contradictions · no recalls
The label itself
What the Supplement Facts panel says
| Magnesium (as magnesium glycinate) | 60mg |
|---|---|
| Magnesium Glycinate | 400mg |
Printed on the package: GMP CERTIFIED Facility · Third-Party Tested · CONTENTS CERTIFIED NSF · NSF · CONTENTS CERTIFIED NSF · GMP CERTIFIED · CONTENTS CERTIFIED · NOW NSF CERTIFIED
We read 2 lines from the package photograph. It is our transcript of the label, not the manufacturer’s panel, and it may be incomplete.
Marketing claims, checked
The checks, one by one
The public sources did not settle the marketing promises on this label.
◐Partly confirmed2
“Muscle, & Heart”
Evidence →Ingredient evidence exists; on dose: label states 60 mg/serving — about 14% of the adult daily reference (adult RDA 310–420 mg elemental; NIH sets 350 mg/day as the supplemental upper level for elemental magnesium). A single serving isn’t meant to supply a full day, so this is context, not a shortfall. Caveat: chelate labels (glycinate, citrate) often state compound mass, which reads ~5–7× higher than elemental magnesium — the Supplement Facts panel settles which is meant.
Ingredient research can support context, but it is not a trial of this exact product.
?Couldn’t verify independently2
“Third Party Tested, Gluten Free, Non-GMO, by Double Wood”
Evidence →No named laboratory or lot-specific certificate was found for this exact product. A related brand page names no testing issuer and links no product-bound report; its UPC is not published. NSF, IFOS, USP, and Informed-Sport were not checked in this record. This is a public-evidence limit, not a finding that testing did not occur.
“in the USA From Globally”
Evidence →“Made in USA” can describe only final bottling. Ingredient-sourcing records were not located for this product.
We looked and found no public proof. That does not count against the product.
Quick read · 3 useful findings
What is worth knowing.
Headlines first. Open evidence only when you want the source trail.
CheckedIs the label honest?
Listing claim matches the Supplement Facts panel
The label promise and the Supplement Facts amount agree.
Evidence and sources
The listing claims 60 mg; the photo-read Supplement Facts panel shows Magnesium (as magnesium glycinate) at 60 mg per serving — the listing text and its photo-read panel agree; this is internal consistency, not independent testing.
Locked evidence record →Open the full source-linked findingCheckedWho is behind it?
The barcode identity checks out · 850033272215.
The barcode matches, so we are checking the right product rather than a look-alike.
Evidence and sources
UPCitemdb resolves 850033272215 to "Magnesium Glycinate - 180 x 400 mg capsules" (Double Wood Supplements) — consistent with this listing.
Locked evidence record →Open the full source-linked findingPublic contextWill you get what you pay for?
Reaching a studied dose costs about $9/month
Comparing cost at a research-relevant amount shows how quickly the package is used and what the routine actually costs.
Evidence and sources
At 3.3 serving(s) a day to reach the low end of the studied range (200–420 mg), this product runs roughly $9 per month. A price observation, not a recommendation.
Locked evidence record →Open the full source-linked findingWhat remains open 1
- We have not found a public label filing for this exact product.
These are evidence gaps, not strikes against the product.
Who owns the brand wordmark?
🇺🇸
Double Wood LLCLimited Liability Company · exact supplement-class mark for DOUBLE WOOD SUPPLEMENTS
Filed address
22 Lindsey Ave, Danville, PENNSYLVANIA 17821, UNITED STATES
USPTO identifies the public owner or applicant behind this brand wordmark. This does not by itself identify the product manufacturer or prove where the product was made. Open USPTO source ↗
Research behind the findings
Dose and research context
The label amount is shown beside the range used in the linked ingredient studies.
Dose vs research
Magnesium
STUDIED RANGE0525 mg
60 mg per serving — below the 200–420 mg/day used in the linked studies.
Linked ingredient research · label amount, not a recommendation
Where it sells
Price check for this exact product
Amazon
Exact UPC/GTIN match$16.99
$0.09 per labeled serving
matching UPC/GTIN · checked Aug 29, 2026
View on Amazon ↗iHerb
Exact UPC/GTIN match$17.95
$0.10 per labeled serving
matching UPC/GTIN · checked Jul 24, 2026
View on iHerb ↗Brand website
Official product-page candidate · UPC absent$47.41
Official shopping lead; excluded from exact price comparisons.
Magnesium Glycinate Extra Strength · Double Pack. Confirm the package UPC/GTIN before buying.
Check brand website ↗Walmart
Not confirmedNo exact listing saved
We only show a price when the seller publishes the same barcode as the bottle. We haven’t found that match here.
Search Walmart ↗Same UPC/GTIN observed across 2 sellers. Amazon was lowest at $16.99; iHerb was highest at $17.95 — a $0.96 range at check time.
The brand-page price is shown as a shopping lead only. It is excluded from the exact-product price difference because the page does not publish this record's matching UPC/GTIN.
Reference prices only · no affiliate links · every compared seller must publish the matching UPC/GTIN.
Want to inspect the evidence?
The full report shows every source, the exact unresolved question, and the documentation that would settle it.
Record built September 03, 2026. Sources: source listing observed at check time · USPTO Trademark Search · Keepa exact-listing history · NIH / published research · certification and regulator records where available. LookCloser publishes evidence and gaps; it does not advise for or against any supplement. Evidence-based corrections welcome.