Bloomingdale, IL—NOW Foods has continued its quality testing of brands found on Amazon, this time testing for Glutathione. The results: Brands were overall of a better quality than in NOW’s previous tests, although there were still brands that failed on potency and heavy metal testing.

As with prior analyses, NOW performed one set of tests in its own labs, and sent samples to Eurofins to do a second, independent set of tests. All products were tested with HPLC analysis, in both labs. The tests included 19 lesser-known brands, and NOW’s own product.

Looking at potency, the majority of the brands were within 90-110% of label claims. Amazing Nutrition only hit 80% of the label claim, Emily Bright Formula met 75% of the label claim, and Eco-Taste only managed to meet 55% of the label claim. Fresh Nutrition, Welessentials, and Nutricost went overboard—the Welessentials product contained 116% of the label claim, the Nutricost product met 114% of the label claim, and Fresh Nutrition’s product contained 140% of the label claim.

One oddball: Skin Whitening Glutathione, a Northern Crown Cosmetics product, didn’t make any label claim for glutathione. When tested, it was found to contain 19-22mg of glutathione. For context, the vast majority of the brands claimed 250-500 mg, with two exceptions: Fresh Nutrition, which claimed 167mg, and Emily Bright Formula, which claimed only 2mg.

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In terms of heavy metals, Emily Bright and Skin Whitening Glutathione tested above Prop 65 levels for lead, while the other 17 brands passed the heavy metals tests.

“The quality of these lesser-known brands purchased on Amazon is greatly improved, but we are still finding unacceptable lapses,” said Dan Richard, NOW’s Vice President of Global Sales and Marketing.

NOW has previously testedALA,phosphatidyl serine,CoQ10, SAMe, andcurcumin.