The bark extract of the African plum tree, known scientifically as Pygeum africanum, has been used for centuries in traditional African medicine. It is now widely available as a dietary supplement, primarily aimed at supporting men’s urinary health. As its popularity has grown, questions have arisen about its potential impact on the endocrine system, specifically whether it alters circulating levels of testosterone. Understanding Pygeum requires separating its localized effects within the prostate from its systemic effects on overall hormone balance.
Primary Use and Active Compounds of Pygeum
Pygeum’s most common modern application is for managing the lower urinary tract symptoms associated with Benign Prostatic Hyperplasia (BPH), the non-cancerous enlargement of the prostate gland. The extract is rich in specific phytochemicals responsible for its therapeutic properties. These biologically active substances are categorized into three main groups that exert effects on the prostate:
- Phytosterols, such as beta-sitosterol, which have anti-inflammatory effects and may reduce swelling within the prostate tissue.
- Pentacyclic triterpenoids, which possess anti-inflammatory properties by inhibiting certain enzymes and growth factors.
- Ferulic acid esters and long-chain fatty alcohols, which may help normalize the secretory activity of the prostate epithelium.
Pygeum’s Interaction with Prostate Hormones
The concern that Pygeum might lower testosterone stems from its theoretical mechanism of action on the prostate gland, which is a hormonally responsive organ. Prostate growth, and the resulting BPH, is significantly influenced by a potent androgen called Dihydrotestosterone (DHT). DHT is synthesized from testosterone within the prostate cells by an enzyme known as 5-alpha reductase (5-AR).
Pygeum’s components interact with this hormonal pathway at the cellular level. Certain phytosterols and other compounds in the extract are believed to act as weak inhibitors of the 5-AR enzyme, similar to some pharmaceutical agents used for BPH. By slightly blocking this enzyme, the conversion of testosterone into the more proliferative DHT is theoretically reduced within the prostate tissue. This localized modulation of the most potent androgen is a key part of the extract’s therapeutic effect.
Furthermore, specific compounds in Pygeum, such as atraric acid, have demonstrated the ability to antagonize the androgen receptor. This means they can interfere with how DHT or testosterone binds to the receptor sites inside the prostate cells, reducing the stimulating signal for cellular growth. This action, combined with anti-inflammatory effects, helps to alleviate urinary symptoms. The mechanism of action is highly focused on reducing the effect of androgens within the prostate, rather than broadly suppressing androgen production throughout the body.
Clinical Evidence Regarding Testosterone Levels
The central question of whether Pygeum lowers circulating testosterone levels is directly addressed by human clinical trials. Scientific investigations have specifically measured serum levels of Total Testosterone (T) and Free Testosterone (FT) in men supplementing with the extract. The available evidence generally suggests that Pygeum does not cause a significant reduction in systemic testosterone levels, despite its localized anti-androgenic activity within the prostate.
In fact, some limited clinical data has indicated the opposite effect, where Pygeum supplementation was associated with a modest increase in plasma testosterone levels in men with BPH. Researchers hypothesize that this unexpected observation may be due to Pygeum’s general anti-inflammatory effects, which could improve the function of the testes and other reproductive tissues. Conversely, an early human study found no substantial changes in circulating levels of testosterone, follicle-stimulating hormone (FSH), or luteinizing hormone (LH) following Pygeum use.
The consensus across multiple studies is that the localized anti-androgenic effects of the extract do not translate into a clinically significant suppression of the body’s overall testosterone production. This distinction is crucial: Pygeum appears to modulate androgen activity in the prostate to relieve BPH symptoms, but the systemic levels of the hormone remain largely unaffected. Pygeum has a favorable safety profile, with reported side effects usually being mild and limited to gastrointestinal irritation or headache. The current body of evidence indicates that Pygeum is unlikely to lower a man’s circulating testosterone levels.