Side effects of Eurycoma longifolia may include insomnia, restlessness and irritability. If taken on its own and in moderation, this herbal extract is generally well tolerated and not associated with severe side effects.
Eurycoma longifolia, which is commonly referred to as Long Jack and traditionally called tongkat ali, is indigenous to Southeast Asia. It is a shrubby tree that can grow up to 30 feet tall.
Its roots and bark are used increase energy, boost sex drive, alleviate symptoms of sexual dysfunction and improve athletic performance and recovery.
Traditionally, tongkat ali was used throughout Southeast Asia for its antimicrobial, antimalarial and antipyretic effects. It was also traditionally used as an aphrodisiac.



- Aphrodisiac & male sexual enhancer
- Increases testosterone & sperm motility
- Improves muscle mass, strength & mood
Eurycoma Longifolia Overview
Tongkat ali remains a popular supplement throughout Southeast Asia and can be commonly found added to energy drinks and coffees.
Tongkat ali remains so popular in Malaysia that E. longifolia is a protected species in that country. Plants used to make supplements are often grown as crops and the roots and bark are harvested for supplement production.
Although Tongkat Ali has a long history of traditional use, contemporary research into the therapeutic effects of the plant is limited. Some of the traditional uses have not yet been studied sufficient to determine efficacy.
There is also insufficient research available to determine the safety of long-term use. To avoid negative Eurycoma longifolia side effects, it is recommended for short-term use.
Eurycoma Longifolia Side Effects
Eurycoma longifolia is rated Possibly Safe by the Natural Medicines database when used appropriately. While it is generally well tolerated, it may cause over-stimulation, anxiety and restlessness, especially at higher dosages.
There is limited clinical research available to determine the prevalence of side effects. Long Jack may increase heart rate and may affect blood pressure, but researchers have yet to conclude if this outcome is positive or negative.
It is not clear what effect Eurycoma longifolia has on the kidneys and liver. Tongkat ali may affect blood glucose levels as well. Speak to your doctor before taking this supplement if you have been diagnosed with Diabetes.
Some individuals have combined Eurycoma longifolia supplements with other herbal aphrodisiacs to enhance the effects. These include yohimbe bark extract, horny goat weed (Epimedium) and maca.
Combining these supplements may cause elevated body temperature, flushing, increased heart rate, irritability and insomnia. In some cases, insomnia has lasted for several days and may cause fatigue or affect mood
To prevent Eurycoma longifolia adverse effects, it is recommended to use it on its own unless you have consulted with your doctor about a specific pairing of supplements. It is important to seek advice from your doctor before starting to take Tongkat Ali.
Eurycoma Longifolia Contraindications
There are some groups who are specifically recommended against taking Eurycoma longifolia extract. In some cases, there is insufficient evidence to determine safety of use for a certain group.
In other cases, there may be a risk of interactions with a specific condition or with medication used to treat that condition.
This supplement is contraindicated for the following individuals:
- Pregnant or nursing mothers;
- Patients scheduled for any type of surgery;
- Women with breast cancer, ovarian cancer or any other hormone-based cancer;
- Individuals with low blood pressure;
- Individuals taking prescription antihypertensive medications;
- Patients who have recently suffered a heart attack;
- Those with bleeding and/or clotting conditions;
- Others groups as dictated by medical professionals.
Although Long Jack roots and bark are natural products, they may cause serious complications for certain individuals. Speak with your doctor to learn more.
Eurycoma Longifolia Research
The list of health benefits attributed to Eurycoma longifolia in traditional medicine practices is long. However, contemporary research has yet to substantiate the majority of therapeutic claims attributed to this plant.
Researchers have identified a number of phytonutrients (plant nutrients) in Long Jack that may have positive effects for health. More research is needed to understand the mechanisms of action for Eurycoma longifolia extract.
The following are some of the effects that have been observed in research trials so far. This includes laboratory and animal studies. Not all of these effects have been demonstrated in human.
- Stimulating the synthesis of osteoblasts (cells that lead to bone development)
- Supporting memory;
- Lowering triglyceride levels;
- Increasing the use and synthesis of human growth hormone;
- Increasing testosterone levels;
- Boosting the synthesis of nitric oxide, which causes vasodilation;
- Improving low blood pressure.
Conclusions
Eurycoma longifolia or Tongkat Ali has been used for in traditional medicine for centuries. It is not commonly associated with serious side effects. However, there is limited currently available clinical research.
Speak to your doctor to determine if this supplement is right for you. Your doctor can help you select the appropriate dosage to reduce the risk of Eurycoma longifolia side effects or drug interactions.
- Chan KL, Low BS, Teh CH, Das PK. The effect of Eurycoma longifolia on sperm quality of male rats. Nat Prod Commun. 2009 Oct;4(10):1331-6.
- Tambi MI, Imran MK, Henkel RR. Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism? Andrologia. 2012 May;44 Suppl 1:226-30.
- Hamzah S and A Yusof. The ergogenic effects of Eurycoma longifolia Jack: a pilot study. British Journal of Sports Medicine 2003;37(5):465-466.
Article last updated on: April 1st, 2018 by Nootriment