Testosterone

Testosterone is the male sex hormone. It affects bone mass, fat distribution, muscle, strength, and mood. Signs of low testosterone include decreased libido, erectile dysfunction, fatigue, increased fat mass, decreased muscle, and lower bone density^1,2,9.

Anabolic steroids are synthetic or human-made versions of testosterone. Due to their adverse side effects, the market for “natural” ways to increase testosterone has exploded. This article focuses on products made from over the counter ingredients such as vitamins, minerals, amino acids, and other supplements. As of this article’s writing, The Supplement Database contained 25 ingredients that claim to increase testosterone levels and 142 products promising to do the same^3,9.

Let’s look at the research on some of the most popular ingredients found in testosterone boosting products.

TL;DR: Young, healthy males on a balanced diet, will probably not see any meaningful benefits in using testosterone boosters containing zinc, tongkat ali, or fenugreek. Older males or males who have low testosterone levels may see some improvement when using these products.

Supplements

Zinc

Zinc is found in 60% of testosterone boosters in the database; it is the most popular ingredient in the product category. There are several studies looking at zinc’s effects on testosterone levels. The first tests whether the mineral has any impact on testosterone levels in cyclists. Participants took 30 mg of zinc per day for four weeks. Their testosterone levels were measured before and after an exhaustive cycling session⁴.

The results showed testosterone levels did not increase after zinc supplementation. The authors of this study noted that there is some evidence that athletes deficient in zinc may see testosterone levels increase after supplementing with zinc. They did not see this benefit in athletes that had sufficient zinc levels before the study began⁴.

The second study was conducted on sedentary males. Participants took 3 mg per kg of body weight per day for four weeks. The participants then performed a fitness test on an exercise bike. The results showed that testosterone levels fell after exercise. Supplementation reduced the decrease in post-exercise testosterone levels⁵.

Verdict on Zinc: Zinc probably doesn’t increase testosterone if you’re on a balanced diet. If you’re not on a balanced diet, it probably won’t help increase testosterone levels more than if you get enough zinc from your diet.

Tongkat Ali

Tongkat ali, also known as eurycoma longifolia or longjack, is found in 54% of testosterone boosters in the database, making it the second most popular ingredient in the category. Tongkat ali is a plant indigenous to South East Asia. Its roots are harvested and used for a wide variety of purposes, including increasing testosterone levels⁶.

The first study looked at over 300 men from 2005 to 2009. This study was primarily interested in tongkat ali’s ability to increase testosterone in men whose levels were low. The men received 200mg per day for a month. The results showed an average increase of 46.8% in testosterone levels⁶.

The second study tested the supplement on 13 athletes. They took 400mg for six weeks. The results of this study did not show increased testosterone levels⁷. Another study tested the supplement on 13 older males. They took 400 mg per day for 5 weeks. The results showed significant increases in testosterone levels⁸.

Verdict on Tongkat Ali: Tongkat Ali probably doesn’t increase testosterone levels in men who are already within a normal range. It may help older men with decreased levels.

Fenugreek

Fenugreek is a clover-like herb found in the Mediterranean region, Southern Europe, and Western Asia. It’s found in 51% of testosterone boosters. Its seeds are used in food, medicine, and cosmetics¹⁰.

A 2018 meta-analysis of four studies looked into fenugreek’s effect on testosterone levels. The studies in this analysis included 206 participants. Two of the studies included young male athletes in their early twenties. One study used healthy males in their early twenties. The last study used healthy males in their 50s. The fenugreek dose used in the four studies ranged from 250mg to 600mg per day for 8-12 weeks. The results in all four studies showed increases in testosterone, though the increases in the younger males were smaller than in the older subjects⁹.

Verdict on Fenugreek: Fenugreek might increase testosterone levels. The increase is probably more significant in older men whose starting levels are lower.

The Bottom Line – Which supplements increase testosterone levels?

The top three ingredients found in testosterone boosters are currently zinc, tongkat ali, and fenugreek. Currently, the evidence does not show that these ingredients significantly increase testosterone levels, at least not in healthy young men who already have normal levels. The evidence is more promising for males (mostly older) whose testosterone levels are low. Fenugreek did see increases for younger males, however, those increases were much smaller than the increases seen in older men.

Recommendation: Young, healthy males on a balanced diet, will probably not see any meaningful benefits in using testosterone boosters containing zinc, tongkat ali, or fenugreek. Older males or males who have low testosterone levels may see some improvement when using these products.

References

1. Wein, H. (2016, April 25). Understanding How Testosterone Affects Men. Retrieved from https://www.nih.gov/news-events/nih-research-matters/understanding-how-testosterone-affects-men
2. Testosterone – What It Does And Doesn’t Do. (2019, August 29). Retrieved from https://www.health.harvard.edu/drugs-and-medications/testosterone–what-it-does-and-doesnt-do
3. Anabolic Steroids DrugFacts. (2020, July 24). Retrieved December 31, 2020, from https://www.drugabuse.gov/publications/drugfacts/anabolic-steroids
4. Neek, L. S., Gaeini, A. A., & Choobineh, S. (2011). Effect of Zinc and Selenium Supplementation on Serum Testosterone and Plasma Lactate in Cyclist After an Exhaustive Exercise Bout. Biological Trace Element Research, 144(1-3), 454-462. doi:10.1007/s12011-011-9138-2
5. Killic, M. (2007). Effect of fatiguing bicycle exercise on thyroid hormone and testosterone levels in sedentary males supplemented with oral zinc. Neuroendocrinology Letters, 5, 681-685.
6. Tambi, M. I., Imran, M. K., & Henkel, R. R. (2011). Standardised water-soluble extract of Eurycoma longifolia, Tongkat ali, as testosterone booster for managing men with late-onset hypogonadism? Andrologia, 44, 226-230. doi:10.1111/j.1439-0272.2011.01168.x
7. Chen, C. K., & Mohamad, W. M. (2014). Supplementation of Eurycoma longifolia Jack Extract for 6 Weeks Does Not Affect Urinary Testosterone: Epitestosterone Ratio, Liver and Renal Functions in Male Recreational Athletes. International Journal of Preventive Medicine, 5(6), 728-733.
8. Henkel, R. R., Wang, R., Bassett, S. H., Chen, T., Liu, N., Zhu, Y., & Tambi, M. I. (2014). Tongkat Ali as a Potential Herbal Supplement for Physically Active Male and Female Seniors-A Pilot Study. Phytotherapy Research, 28(4), 544-550. doi:10.1002/ptr.5017
9. Mansoori, A., Hosseini, S., Zilaee, M., Hormoznejad, R., & Fathi, M. (2020). Effect of fenugreek extract supplement on testosterone levels in male: A meta‐analysis of clinical trials. Phytotherapy Research, 34(7), 1550-1555. doi:10.1002/ptr.6627
10. Fenugreek. (n.d.). Retrieved from https://www.nccih.nih.gov/health/fenugreek