Testosterone booster dietary supplement products claim to increase the male sex hormone testosterone, which affects muscle strength, endurance, and male sexual performance. There is insufficient evidence to support the claims for the many “natural ingredients” on the market. These ingredients include Tribulus terrestris, Eurycoma longifolia (Tongkat Ali or Longjack), Urtica dioica (stinging nettle), fenugreek, Mucuna pruriens (cowhage), D-aspartic acid, Bulbine natalensis, Saw palmetto, Epimedium grandiflorum (horny goat weed), diindolylmethane (DIM), maca, and a wide range of botanical extracts, plant steroids, and flavones.
Some testosterone booster dietary supplements actually contain drugs that increase natural testosterone production in various ways. Undeclared drugs, anabolic steroids, SARMs, aromatase inhibitors, and other potentially problematic ingredients have been found in such products, but none of these drugs are allowed in dietary supplements. Both types—those with permitted ingredients and those adulterated with drugs—fall in the class of high-risk dietary supplements.
Updated 23 May 2016