Tongkat ali — The Phytoandrogen

Tongkat ali contains bioactive eurypeptides and quassinoids, such as eurycomanone, which are thought to stimulate the release of free testosterone from its binding proteins (SHBG). It may also influence the hypothalamic-pituitary-gonadal axis by increasing luteinising hormone (LH) and follicle-stimulating hormone (FSH) secretion, thereby promoting testosterone synthesis in Leydig cells. Additionally, eurycomanone has been shown in vitro to inhibit the aromatase enzyme, reducing the conversion of testosterone to oestrogen. Its adaptogenic effects are partly mediated by reducing cortisol and increasing the testosterone-to-cortisol ratio, mitigating the impact of chronic stress.

Multiple randomised controlled trials have investigated Tongkat ali in men with late-onset hypogonadism or androgen deficiency. A 6-month trial (Leitão et al., 2021, Maturitas) found that 200 mg/day combined with concurrent training improved erectile function and increased total testosterone levels. An earlier 1-month study (Tambi et al., 2012, Andrologia) in 76 men with late-onset hypogonadism reported significant increases in serum testosterone and improvements in the Ageing Males' Symptoms scale.

200–400 mg/day of standardised water-soluble extract is the most studied range in human trials. Typically taken in the morning with food. Cycling (e.g., 5 days on, 2 days off) is sometimes recommended by practitioners, though long-term continuous use up to 6 months has been studied.

Generally well-tolerated at standard doses up to 6 months. High doses may cause irritability, insomnia, or restlessness. It is contraindicated in pregnant and lactating women, and in individuals with hormone-sensitive cancers (such as prostate or breast cancer). Caution is advised for those with liver or kidney disease, and it may interact with hypoglycaemic medications.

Key Papers