Independent testing: what is actually in the capsule.
A label claim is not proof of content. These third-party test programs buy products off the shelf and measure them. We reference their results because they are the only way to know what a bottle really contains.
Independent lab testing
What happens when you actually test what is in the bottle. We link every claim to the lab that did the testing.
A 2021 independent lab analysis of 22 popular NMN products sold on Amazon found that 14 contained less than 1% of the NMN stated on the label, including three where none was detected. The bottles were labelled NMN; the capsules were not. The testing was performed by HPLC with UV-Vis detection, a standard analytical method. The lab that conducted the analysis also sells a competing NAD precursor product (NR), which is a commercial interest worth noting when weighing the findings. The methodology is sound; the conflict of interest does not change the test results, but readers should know it exists. Read the 2021 analysis →
For NR (nicotinamide riboside), ConsumerLab tested 70 products. 26 came close to their declared amounts. The rest fell short of label or failed on quality markers. NR is the better-studied NAD+ precursor on the human trial record, but the shelf is no more honest than NMN's. ConsumerLab NR review →
Resveratrol products fared better on content. The brands ConsumerLab reviewed generally contained the amounts they declared. Content honesty and clinical effect are different questions, though. The human evidence for resveratrol as a longevity intervention is weak, and a 2025 GRADE-assessed meta-analysis found no SIRT1 effect. A capsule that contains what the label says is still a capsule of something unproven. Read our resveratrol evidence review →
The regulatory backdrop for NMN keeps moving. The FDA changed its position on NMN as a dietary supplement, and Amazon and Walmart have periodically stopped selling NMN products in response. When a category is regulatory contested, the risk of mislabelled or reformulated stock rises. See the regulatory timeline →
Stiftung Warentest
German consumer testing foundation. Independent of industry, funded by the public and by subscriptions.
Stiftung Warentest reviewed 15 beauty drinks containing collagen and hyaluronic acid. All 15 failed. Its verdict was titled "teuer und überflüssig", expensive and unnecessary. None of the products delivered a benefit that justified the price.
Only 10 of the 15 manufacturers responded to inquiries about the studies they cited to support their claims. Five would not back up their own marketing with the source data.
Nearly all of the tested products had a different composition from the studies they referenced. The trial used ingredient A at dose X; the drink contained ingredient B at dose Y. A different formula is a different product, and a different product cannot borrow the evidence of the original.
The EU's Health Claims Verification Ordinance (HCVO) prohibits unregulated health claims like "Anti-Aging-Drink". Stiftung Warentest applies that rule directly: a beauty drink marketed on an unauthorised claim fails on that basis alone, before the lab work even starts.
Labdoor
US supplement rating service. Scores products on label accuracy, purity, and nutritional value.
Labdoor buys products in store, not from the manufacturer, and sends them to FDA-registered laboratories for testing. Buying retail stock closes the most common loophole in supplement testing: a brand can send a clean sample to a lab and sell a different batch to customers. Labdoor tests what customers actually receive.
Labdoor maintains ranking pages for NMN and NAD products. Each product gets a score and a breakdown of what was found versus what was claimed.
Its methodology is more transparent than most. Labdoor publishes what it tests for: label accuracy, heavy metals, and the active ingredient. A reader can see exactly which checks a score rests on, and which checks were not run.
Renue by Science berberine lab test
A published third-party purity test of three berberine brands.
A published independent lab test compared the purity of three berberine brands. Renue by Science berberine returned the lowest purity at 82.6%. DoNotAge berberine returned 99.7% purity. The gap is wide enough to change the effective dose a customer actually takes.
Purity at 82.6% means a capsule labelled 500 mg delivers roughly 413 mg of berberine. A capsule at 99.7% delivers close to the full 500 mg. Two products with the same label can give different doses in practice. Renue by Science berberine product page → DoNotAge berberine product page →
ConsumerLab: Omega-3 fish oil
27 products tested for freshness, contamination, and label accuracy. Rancidity is the failure mode.
ConsumerLab purchased and tested 27 fish oil, krill oil, and algal oil supplements. Three products exceeded oxidation limits, meaning the oil was rancid. Rancid fish oil contains oxidized lipids that may cause the opposite of the intended benefit. Eleven of 68 products reviewed across the full test program had contamination, label, or quality issues that caused them to fail.
Fish oil is the supplement most vulnerable to oxidation because omega-3 fatty acids are polyunsaturated: the double bonds that make them biologically active also make them chemically fragile. A product that was clean when manufactured can be rancid by the time it reaches a customer if storage conditions were poor. Freshness is not guaranteed by the label; it has to be measured.
ConsumerLab tests for total omega-3 fatty acids (EPA and DHA), freshness markers (peroxide value, anisidine value, TOTOX), and heavy metals (lead, mercury, arsenic, cadmium). The TOTOX score combines two oxidation measures and is the single most important freshness indicator. ConsumerLab fish oil review →
ConsumerLab: Ashwagandha
Only 38% of ashwagandha products passed testing. One of the highest failure rates ConsumerLab has reported.
ConsumerLab selected and tested popular ashwagandha supplements. Only 38% passed. The rest failed on withanolide content, contamination, or label accuracy. Ashwagandha's active compounds are withanolides, and the concentration in a root extract depends on the extraction method, the part of the plant used, and the growing conditions. A product labelled "standardized to 5% withanolides" may contain far less.
The failure pattern is similar to the NMN analysis: the ingredient is expensive, the category is trendy, and the analytical methods for verifying content are not simple. Consumers buy ashwagandha for stress and sleep. A product that contains little to no active withanolides is an expensive capsule of rice flour. ConsumerLab ashwagandha review →
ConsumerLab: Berberine (updated)
7 of 13 berberine brands tested had little to no detectable berberine. A separate test found lead contamination in goldenseal products.
In a ConsumerLab product update dated October 2025, 7 of 13 berberine brands had little to no detectable berberine. The original review tested 10 products: 5 of 6 berberine supplements passed, but all 3 goldenseal supplements (goldenseal contains berberine as a primary alkaloid) failed. One contained almost none of the expected berberine, and two were contaminated with lead.
Lead contamination in a berberine product is notable because berberine is taken daily for blood sugar management. Chronic low-dose lead exposure accumulates. The consumer who buys a berberine supplement for metabolic health and gets lead instead is receiving the opposite of what they paid for. ConsumerLab berberine review →
ConsumerLab: Multivitamins
32% of multivitamins failed testing. 1 in 3 products on the shelf did not contain what their labels claimed.
ConsumerLab tested 22 multivitamins and found that 7 (32%) failed to meet quality standards. The failures were confirmed by a second independent laboratory. The problems included incorrect amounts of listed ingredients, failure to disintegrate properly (meaning the tablet would pass through the body without releasing its contents), and contamination issues.
A multivitamin that does not disintegrate is a tablet that delivers nothing. A multivitamin with too much of a fat-soluble vitamin carries a toxicity risk that the label does not signal. The 32% failure rate is one of the highest ConsumerLab has reported for any supplement category. The category is also the one consumers trust most by default: people who take a multivitamin tend to assume it is safe and accurately labelled. ConsumerLab multivitamin review →
ConsumerLab: Turmeric and curcumin
19 products tested. All contained claimed curcuminoids, but one was contaminated with lead.
ConsumerLab tested 19 turmeric and curcumin supplements and spices. All selected products contained the amounts of curcumin compounds expected from their labels. This is a positive result for content accuracy in a category where it matters: curcumin is poorly absorbed, and products use various delivery systems (liposomal, phytosome, piperine-enhanced) to improve bioavailability.
However, one product was contaminated with lead. Turmeric is a known source of lead contamination because some producers use lead chromate as a pigment to enhance the yellow colour. The FDA has issued warnings about lead in turmeric products. Lead in a daily-use supplement for inflammation management is a cumulative toxin delivered with every dose. ConsumerLab turmeric and curcumin review →
ConsumerLab and Stiftung Warentest: Vitamin D
Two independent testers, two different failure modes: overdosing and underdelivering.
ConsumerLab tested 26 vitamin D supplements and found that 2 products contained up to twice the amount of vitamin D listed on the label. Vitamin D is fat-soluble, which means excess is stored in body fat rather than excreted. A product that delivers 10,000 IU when the label says 5,000 IU creates a cumulative overdose risk over time, particularly for older adults who are the primary users of vitamin D supplements.
Stiftung Warentest tested 25 vitamin D preparations sold in Germany and recommended only 2 without reservation. Five were explicitly not recommended. Two products had significant deviations between the declared and actual vitamin D content. Stiftung Warentest also noted that many people who take vitamin D supplements do not actually need them: supplementation should follow a blood test, not a guess.
The contrast between the two testing programs illustrates why independent verification matters. ConsumerLab found products with too much. Stiftung Warentest found products with too little. Both are problems, and neither is visible from the label. ConsumerLab vitamin D review → Stiftung Warentest vitamin D test (German) →
ConsumerLab: CoQ10 and ubiquinol
20 products tested. All contained their claimed amounts. Content honesty is not the same as clinical efficacy.
ConsumerLab purchased and tested 20 CoQ10 and ubiquinol supplements. All products were found to provide their listed amounts of CoQ10 or ubiquinol. This is a positive result for label accuracy in a category where the active ingredient is expensive to manufacture and where the ubiquinol (reduced) form is notably pricier than the ubiquinone (oxidized) form.
The test also checked for heavy metals (lead, arsenic, cadmium, mercury) by ICP-MS. No contamination issues were reported. The cost comparison, however, showed a wide price spread: the cost to obtain an equivalent dose of CoQ10 ranged dramatically across products, with some brands charging 5 to 10 times more per milligram without offering a measurable quality difference.
CoQ10 is relevant to longevity because it is a mitochondrial coenzyme involved in ATP production and is one of the few supplements with human evidence for age-related decline. The content test passed. The clinical question (does supplemental CoQ10 slow aging in humans?) remains open. ConsumerLab CoQ10 review →
ConsumerLab: Glycine
10 products tested. All contained claimed amounts. The cost spread was the notable finding.
ConsumerLab tested 10 popular glycine powders and capsules. All products contained their expected amounts of glycine, confirmed by HPLC. Heavy metals (arsenic, cadmium, lead, mercury) were tested and no contamination issues were reported. Glycine is a simple amino acid, and the analytical verification is straightforward.
The notable finding was the cost spread. The price to obtain a 3-gram dose of glycine ranged from 9 cents to over $1.00 across the tested products. The ingredient is the same molecule in every bottle. A customer paying $1.00 for 3 grams of glycine is paying 10 times more than necessary for the same active compound, with no quality advantage.
Glycine has human evidence for sleep quality and collagen synthesis, and is one of the amino acids tracked on NO1GEVITY. The test result is reassuring for content, and the price comparison is actionable: the cheapest product that passes testing delivers the same benefit as the most expensive. ConsumerLab glycine review →
Why NO1GEVITY references these tests
NO1GEVITY treats independent testing as a transparency-critical data source. A label claim is a claim, not proof. A certificate of analysis from the brand's own contracted lab is better than nothing, but it still tests a sample the brand chose. Third-party verification, where the tester buys the product and measures it, is the only way to know what is actually in the capsule a customer receives.
That is why our quality transparency rewards products with publicly linked, third-party-tested certificates of analysis, and docks products that claim "tested by independent lab" with no document behind the claim. The full rule is published. Read the scoring methodology →
These test programs are not perfect. ConsumerLab is subscription-only, Stiftung Warentest covers a German product set, and Labdoor does not test every brand. But each one closes a gap that self-reporting cannot. Where we cite a test result on a product page, we link the source so you can read it yourself.