They can state that glutathione 'supports antioxidant activity' or 'promotes cellular health' because those are structure-function claims permitted under 21 CFR 101.93
Biol Trace Elem Res 193:334341 Jonard S, Dewailly D (2004) Follicular excess in PCOS
Safety Measurements Theyre also obsessed with safety
Data Privacy Notice: FeelGood's telehealth services involve the collection and processing of sensitive health information by the platform, a licensed medical group (OpenLoop Healthcare Partners, PC), and a third-party compounding pharmacy
Nappo F, Esposito K, Cioffi M, Giugliano G, Molinari AM, Paolisso G, Marfella R, Giugliano D: Postprandial endothelial activation in healthy subjects and in type 2 diabetic patients: role of fat and carbohydrate meals
The reason there is no single "winner" brand is that copper peptide serums vary along several axes at once concentration, chelation form, pH, texture, supporting ingredients and price