6 of 12 Top-Selling Glutathione Supplements on Amazon Fail Label Claims in Independent Testing, Cata-Kor Finds

Cata-Kor, a U.S. based nutraceutical company focused on science-informed longevity formulations, released results from independent laboratory testing of 12 top-selling glutathione supplements purchased from Amazon.com in April 2026. Of the 12 products tested, 6 failed to meet their label claims for glutathione content. Testing was conducted by Swift Laboratory, an ISO 17025:2017-accredited third-party testing facility (ANAB Certificate No. AT-2969), using

HPLC — the standard analytical method for quantifying reduced glutathione in dietary supplements.

The findings point to a broader quality problem in the glutathione category on Amazon, where liposomal and high-dose products have proliferated without consistent independent verification.

Testing Methodology

Products were purchased directly from Amazon.com in April–June 2026 and submitted to Swift Laboratory (Ontario, CA) for independent analysis. Glutathione content was quantified by HPLC per serving as stated on each product label.

Key Findings

Of 12 brands tested, 6 failed to contain the stated amount of glutathione. The results varied significantly in severity. Zeylamum, which claims 1,300 mg of L-Glutathione per serving, had no detectable glutathione. Cenffitio, claiming 600 mg, also returned no detectable glutathione. Starehonorr, claiming 1,000 mg, returned less than 20 mg — under 2% of the label claim. Prunucis, claiming 1,200 mg, returned only 31.6 mg. CORPORALIGHT claimed 1,500 mg and returned 256 mg. Alpha Flow, claiming 1,100 mg, returned only 311 mg — less than 30% of the label claim.

Six brands — Dr. Mercola, BodyBio, TERRA ELMNT, DEAL SUPPLEMENT, Fresh Nutrition, and Cata-Kor — met or exceeded their label claims.

Cata-Kor's own Liposomal Glutathione passed testing across all measured parameters. Independent analysis by Swift Laboratory confirmed 1,082 mg of L-Glutathione Complex per serving against a label claim of 1,000 mg — exceeding the stated amount. The same test confirmed label accuracy for all co-ingredients: Vitamin C (64.8 mg vs. 50 mg claimed), Riboflavin (6.79 mg vs. 5 mg claimed), Selenium (71.0 mcg vs. 55 mcg claimed), and Resveratrol (114 mg vs. 100 mg claimed). Heavy metals testing confirmed results well within USP safety limits.

"Label accuracy is the baseline, not a differentiator," said Roman Miroedov, PhD, Product Development Lead at Cata-Kor. "When 6 of 12 products we tested failed to deliver what the label claims, that is a consumer protection issue. We are publishing these results because buyers deserve to know what they are actually getting.''