The bark of Pausinystalia yohimbe, a tree indigenous to Western Africa.  The active ingredient in yohimbe is the alkaloid yohimbine.  Yohimbe bark extracts are often added to fat loss supplements and/or “male” enhancement supplements, although the amount of yohimbine is variable, and often low.

An alkaloid that’s the active principle in yohimbe (bark of the African tree, Pausinystalia yohimbe).  Yohimbine hydrochloride is sold as a prescription drug for erectile dysfunction.  Yohimbine is also used to treat xerostomia (dry mouth).

Yohimbine (either in standardized form or as yohimbe bark extract) is frequently used in “male enhancement” products, as well as fat loss supplements.  Yohimbine stimulates lipolysis by increasing blood flow in adipose tissue and blocking the activation of a ₂-adrenoceptors on fat cells…although it works better in theory than in fact.

Yohimbine is associated with a number of adverse effects, and should be avoided by individuals with hypotension (low blood pressure), diabetes, and heart, liver or kidney disease.

See David Tolson’s article “Yohimbine Science” for more information.

See Ginger.

Also known as Stinging Nettle. Urtica dioica has been used as a folk medicine for centuries. Stinging nettle extracts are also used as an alternative therapy for benign prostatic hyperplasia (BPH, or enlarged prostate).

Cell culture experiments have shown that Urtica extracts can inhibit the binding activity of SHBG (sex hormone binding globulin). SHBG binds to testosterone, and high levels limit the amount of free testosterone able to interact with the appropriate receptors. 

Urtica extracts are also used in various bodybuilding/testosterone-boosting supplements, although no human studies have been done to demonstrate that a) SHBG binding is the mechanism for Urtica’s effects on BPH; or b) Urtica extracts actually increase free testosterone in humans.

A carotenoid, which – like lutein – concentrates in the lens and retina, and exerts protective effects against age-related macular degeneration and cataract formation.  Zeaxanthin is found with lutein in dark green leafy vegetables and (also like lutein), has no pro-vitamin A activity.

See the Linus Pauling Institute Micronutrient Information Center for more information.

An alkaloid derived from periwinkle that affects cerebral blood flow, memory and learning. Vinpocetine is often added to pre-workout, stimulant blends designed to improve focus, concentration and training drive.

For more information, see “A Review of Nutrients and Botanicals in the Integrative Management of Cognitive Dysfunction” in the Alternative Medicine Review.

See: Coenzyme Q10.

Yerba mate (sometime labeled as mate, or Ilex paraguariensis) is a South American shrub of the holly family. It is commonly used to create a “tea like” infusion called “maté.” A potent antioxidant, it is also a rich source of xanthines (caffeine, theobromine, and theophylline) and chlorogenic acid-the most likely reason for its inclusion in many popular weight loss products. See the full review for complete details.