Weight loss and thermogenic dietary supplements often claim to promote weight loss by increasing metabolic activity. This study characterized the identity and quantity of common supplement ingredients. Commercially available products (n=98) whose name, label, or packaging referenced promotion of thermogenesis or weight loss were identified at retail outlets or web search. Product ingredients were divided into 6 possible categories of ingredient quantity based on packaging. Extracts included raw plant ingredients, plant extracts, etc. Small molecule isolates included caffeine, melatonin, etc. The remaining 4 ingredient categories were lipids, minerals, vitamins, and amino acids. Product suggested serving size was 13±16 grams (40±71 Cal). Green tea (521±1334 mg), cayenne (57±46 mg) and black pepper (5±2 mg) extracts were the most common, with 22 ingredients of 137 extracts being quantified 3 or more times. Caffeine (181±59 mg), acetyl-L-carnitine (595±368 mg) and L-carnitine (510±345 mg) were the most common small molecule isolates, with 11 of 49 total ingredients quantified in at least 3 products. There were 18 different lipid or fatty acid ingredients with only linoleic (740±718 mg) and lipoic (250±235 mg) acids being quantified in at least 3 products. Chromium (268±282 µg), calcium (156±110 mg), and iodine (145±85 mg) were the most common minerals, with 10 of 14 minerals quantified in at least 3 products. Cobalamin (49±78 µg), pyridoxine (8±9 mg) and folate (391±252 mcg) were the 3 most common vitamins, with 5 of 13 vitamins quantified in at least 3 products. Alanine (2133±924 mg), tryptophan (60±40 mg) and tyrosine (250±229 mg) were the most common amino acids, with 3 of 9 amino acids quantified in at least 3 products. Ingredients were indicated as “present” but not quantified 541 times across the 98 products. Proprietary formulas and vaguely worded ingredients were listed in 44 of the 98 products. The 98 thermogenic and weight loss products contained a tremendous variety of ingredients, although only 53 of the 240 different ingredients were present in 3 or more products. Variable ingredient content and quantity, complicate blanket claims about function, efficacy, or safety. Future evaluations of ingredient contents should determine if specific amounts confer discernable benefits. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Moser et al. (2026) studied this question.