Hello
Rat study: Tongkat Eurycomanone may be key active ingredient.
https://www.ncbi.nlm.nih.gov/pubmed/23261482
Study looked at the effect of different extracts of Tongkat Ali. Treatment with a eurycomanone rich fraction of Tongkat Ali, led to:
- Increased sperm production.
- Larger pup litter size delivered from the females after mating with the males treated with F2
- Plasma testosterone (but this was only true at day 26 and 52. At day 104 it was not significantly different from control.
- Plasma LH and FSH levels of the rats treated with 25mg/kg of F2 were higher than those of the control
-In contrast, the plasma estrogen level was significantly lower than that of the untreated control
The study also looked at cultured Leydig cells - isolated quassinoids, eurycomanone and 13α(21)-dihydroeurycomaone significantly increased the testosterone.