Positives

• In a 12-week trial of older men with low testosterone, both 100 mg and 200 mg of Eurycoma longifolia (tongkat ali) reduced fatigue scores compared with placebo, with the treatment groups showing significant fatigue reduction over time and the placebo group showing no change PMC.
  
  
• A 2012 study of 76 older men with low testosterone showed 200 mg/day of tongkat ali extract significantly increased testosterone to normal values in over 90% of participants — relevant for the subset of male Long COVID patients with testosterone suppression PMC.
  
  
• Tongkat ali contains quassinoids (eurycomaoside, eurycolactone, eurycomanone) thought to improve cellular energy use and endurance, with several small studies in athletes showing reduced perceived exertion and improved strength Healthline.
  
  

Negatives

• Benefits typically take several weeks to appear and are most consistent in patients with documented baseline testosterone deficiency — women, younger men with normal testosterone, and patients without androgen-related fatigue tend not to see meaningful effects Examine.
  
  

Hurdles & Side Effects

• A documented case of acute liver injury following tongkat ali supplementation has been reported, prompting LiverTox to flag the supplement as a rare cause of drug-induced hepatotoxicity; baseline LFTs and 3-month follow-up monitoring are reasonable for chronic users LiverTox.