Eurycoma Longifolia Jack

Eurycoma Longifolia Jack is the herb name for what is more commonly known as Tongkat Ali, Malaysian Ginseng, or Longjack.

The aphrodisiac effects of Eurycoma are quite reliable and appear to span a large variety of animal models, limited evidence in female rats but it appears to affect these to a similar extend as in males. It is difficult to do a comparative analysis between other herbal aphrodisiac to assess potency, but Eurycoma is anecdotally one of the better ones.

In addition to the aphrodisiac effects, Eurycoma can also increase sperm production and may directly act as a proerectile agent. At least one molecule in Eurycoma (9-hydroxycanthin-6-one) is associated with both a delay in ejaculation as well as pro-erectile properties (although the ability of this molecule to act via consuming Eurycoma extract is not known).

Hormonally, Eurycoma appears to have remarkable anti-estrogenic effects in vitro and has a potency similar to Tamoxifen when the active ingredient is injected. Promising, but no human studies exist on it currently or studies assessing oral intake of Eurycoma Extract. On the testosterone side of things, the literature appears to be needlessly promising. No peer-reviewed evidence currently establishes Eurycoma as a testosterone booster in otherwise healthy persons or rats but many studies are quick to cite presentations by an M.I Tambi claiming these boosts in testosterone. None of Dr.Tambi's research presented in conferences appears to be indexed in Medline and the claims expressed cannot be proven.

The standard dosage of eurycoma longifolia jack is 200-300mg of a 100:1 extract (the concentration is based on the eurycomamone content), which at least in regards to eurycomamone is as effective as 20-30g of the dry root of the plant.

This dose tends to be taken in 1-2 doses throughout the day, and it is unsure if this is the optimal dose.

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects eurycoma longifolia jack has on your body, and how strong these effects are.

Grade	Level of Evidence [show legend]
	Robust research conducted with repeated double-blind clinical trials
	Multiple studies where at least two are double-blind and placebo controlled
	Single double-blind study or multiple cohort studies
	Uncontrolled or observational studies only

Level of Evidence ? The amount of high quality evidence. The more evidence, the more we can trust the results.	Outcome	Magnitude of effect ? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.	Consistency of research results ? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.	Notes
	Cortisol	Minor	- See study	In stressed persons, daily supplementation of eurycoma is associated with a 16% reduction in cortisol concentrations.
	Erections	Minor	- See study	There appears to be a slight proerectile effect of eurycoma supplements as assessed by self-report survey
	Libido	Minor	- See study	An increase in libido is seen with prolonged daily ingestion of eurycoma supplements in the range of 8.4-10.8%
	Seminal Motility	Minor	- See study	Sperm motility appears to be increased, with more efficacy in those with lower baseline motility and improvements averaging 44.4%
	Sperm Quality	Minor	- See study	May increase parameters of sperm quality and volume.
	Stress	Minor	- See study	Supplementation of eurycoma in stressed persons appears to reduce subjective perceptions of stress.
	Subjective Well-Being	Minor	- See study	In otherwise normal men supplementing eurycoma, an increase in overall quality of life and happiness is seen (alongside increases in libido)
	Weight	Minor	- See study	A decrease in weight has been noted in overweight and obese men, but did not extend to men of normal weight. Mechanisms unknown.
	IGF-1	-	- See study	No detectable alterations in IGF-1 for eurycoma extract
	Serum DHEA	-	- See study	No significant changes in the sulfate form of DHEA (DHEA-S) is noted after twelve continual weeks of supplementation
	Sex Hormone Binding Globulin	-	- See study	No significant influence on circulating SHBG over the course of 12 weeks in otherwise healthy men.
	Testosterone	-	Moderate See all 3 studies	Although the protective effects of tongkat ali on the testicles and the profertility effects may result in a slight increase in testosterone in infertile men and the adaptogenic effects may cause a preservation of testosterone in stressed men, there is no evidence in otherwise healthy and unanxious men.
	Lean Mass	Minor	- See study	One pilot study has noted an increase more than control when both eurycoma and control were paired with exercise
	Power Output	Minor	- See study	A slight increase in power output has been noted, which may be secondary to increased training adaptations
	Fat Mass	-	- See study	No significant known influences on fat mass