Constituents
Agylcon (the nonsugar component of a glycoside molecule that results from hydrolysis of the molecule)
Flavonols: Quercetin, Myricetin and Kaempferol were confirmed by direct comparison with the standard chemicals.
Five flavonol derivatives were identified from E. longifolia

Composition and chemical analysis
Some of the substances in the bark include quassinoids, squalene derivatives, biphenylneolignans, tirucallane-type triterpenes, canthine-6-1, and beta-carboline alkaloids. Additional substances include eurycomanone, longilactone, 14,15beta-dihydroxyklaineanone, 15beta-acetyl-14-hydroxyklaineanone, 6alpha-hydroxyeurycomalactone, eurycomaoside, and eurycomalactone. Eurycomanone is a bioactive quassinoid. Beta-carboline alkaloids are also present in the root.

Tongkat Ali: A review on its ethnobotany and pharmacological importance.
Fitoterapia. 2010. Bhat R, Karim AA. Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia,, Penang, Malaysia.
The plant parts have been traditionally used for its antimalarial, aphrodisiac, anti-diabetic, and antimicrobial activities, which have also been proved scientifically. The plant parts are rich in various bioactive compounds such as eurycomaoside, eurycolactone, eurycomalactone, eurycomanone, and pasakbumin-B among which the alkaloids and quassinoids form a major portion.

Benefits
Eurycoma herb has been used in Thailand, Malaysia, and other southeastern Asian countries as a sexual stimulant, energy booster, and to fight malaria. Extracts of the plant have been shown to possess cytotoxic, antimalarial, anti-ulcer, antipyretic and plant growth inhibition activities.

How long does it take to work?
Unlike prescription medications that are used for impotence or erectile dysfunction, eurycoma does not work in an hour. It normally takes one to four days for this herb to enhance sexuality. The quickness of the sexual benefits depends on dosage, and higher amounts will provide sexual enhancement the first day. However, adverse effects are much more likely on these higher dosages. If you have any medical problems, taking medications, or are over the age of 50, discuss with your doctor before using Tongkat Ali supplements. Blood pressure medications - If you have moderate to severe hypertension, we suggest not using Eurycoma products unless the dosages are very low.

Side effects, risks, safety, danger, caution
Eurycoma herb is very potent and side effects can occur quite easily. These include excess energy, restlessness, aggressiveness leading to arguments, increased body temperature, sweating, rapid heart rate, and insomnia. These adverse effects can be reduced by taking smaller dosages.

Animal Studies
Sexual enhancement, libido, erectile function, impotence

Influence of Eurycoma longifolia on the copulatory activity of sexually sluggish and impotent male rats.
J Ethnopharmacol. 2009. Department of Biomedical Sciences, Section of Pharmacology, University of Modena and Reggio Emilia, Modena, Italy.
In the study we evaluated the influence of Eurycoma longifolia Jack on sexual behavior (including both motivation and copulatory performance) of sexually sluggish and impotent male rats. The root powder of the plant was orally administered to adult Sprague-Dawley male rats, classified as sexually sluggish or impotent taking in account their behavior in pre-experimental tests. Groups of 8 animals each were submitted to three different types of treatment: (1) acute at 3 dose levels (250, 500 and 1000 mg/kg); (2) subacute (daily for 6 days) at the dose of 500 mg/kg and (3) subchronic (daily for 12 days) at the same dose (500 mg/kg). Mount, intromission and ejaculation latencies and post-ejaculatory interval were recorded during the mating test in order to evaluate sexual performance. In addition the partner preference test was used to assess sexual motivation. Testosterone serum levels were measured in subacutely treated rats and compared with the values of controls receiving vehicle. Eurycoma longifolia root improved sexual performance but not motivation in sluggish rats after acute or subacute administration. The effect could be mainly ascribed to increased testosterone levels.

Sexual arousal in sexually sluggish old male rats after oral administration of Eurycoma longifolia Jack.
J Basic Clin Physiol Pharmacol. 2004; Ang HH, Lee KL, Kiyoshi M. School of Pharmaceutical Sciences, University Science Malaysia, Minden, Penang, Malaysia.
The objective of this study is to evaluate sexual arousal in sexually sluggish old male rats, 24 months old and retired breeders, receiving 200, 400, or 800 mg/kg of various fractions of E. longifolia Jack, twice daily, for 10 days. The aphrodisiac effect was monitored by the act of yawning and stretching because yawning, either alone or associated with stretching, is considered an ancestral vestige surviving throughout evolution that promotes sexual arousal. The results showed that 800 mg/kg of E. longifolia Jack increased yawning by 50% and stretching by 16% in sexually sluggish old male rats, by 700% and 150%, respectively, in sexually active male rats, and by 30% and 100%, respectively, in middle aged, 9 months old and retired breeders. We conclude that the results of this study support the folk use of this plant as an aphrodisiac.

Eurycoma longifolia Jack enhances sexual motivation in middle-aged male mice.
J Basic Clin Physiol Pharmacol. 2003; Ang HH, Lee KL, Kiyoshi M. School of Pharmaceutical Sciences, University Science Malaysia, Minden, Penang, Malaysia.
Eurycoma longifolia Jack was investigated for sexual motivation activity in adult, middle-aged male mice and in retired breeders. Each mouse received 500 mg/kg of one of 4 fractions of E. longifolia, viz. chloroform, methanol, butanol, and water, whereas the mice in the control and yohimbine groups received 3 ml/kg of normal saline and 30 mg/kg of yohimbine daily respectively for 10 d. The results show a transient increase in the percentage of male mice responding to the right choice after chronic consumption of the fractions with 50 percent of the adult middle-aged male mice treated with E. longifolia Jack and yohimbine scoring the right choice after 8 and 5 days post-treatment respectively. In conclusion, this study has shown that Eurycoma longifolia Jack continues to enhance sexual motivation in adult, middle-aged male mice and in retired breeders.