Testosterone Boosters Intake in Athletes: Current Evidence and Further Directions
Open accessAbstract
“Testosterone boosters” (TB)—are supplements that are claimed to increase testosterone levels in the human body. While the consumption of TB may be popular among athletes, there is insufficient evidence both about the safety and the real efficacy of TB. In our review, we searched MEDLINE/PubMed and Cochrane Library for studies on the effects of 15 substances that are claimed to increase testosterone levels Anacyclus pyrethrum; Bulbine natalensis; Epimedium (horny goat weed); L-arginine; L-carnitine; magnesium; Mucuna pruriens; pantothenic acid; selenium; shilajit Eurycoma longifolia (Tongkat Ali); Serenoa repens (saw palmetto); boron; Withania somnifera (ashwagandha); and Trigonella foenum-graecum (fenugreek) in athletes and healthy adults under 55 years of age. We found such studies regarding 10 out of 15 substances: L-arginine (3 studies); L-carnitine (2); magnesium (1); selenium (2); shilajit (1); Tongkat Ali (2); Serenoa repens (1); boron (3); ashwagandha root (2); and fenugreek (7). Many of them fail to prove the efficacy of these substances to increase testosterone levels. Tongkat Ali, ashwagandha, and fenugreek were the substances with the strongest evidence. The positive effect of magnesium and shilajit on testosterone concentration was shown in single studies. Conflicting data found that L-arginine, L-carnitine, Serenoa repens, selenium and boron do not appear to increase testosterone levels. There are almost no data on the safety profile of various TB components; however, certain TB components may be linked to coagulation, and pancreatic and hepatic disorders. Based on the review, the authors conclude that at present TB cannot be recommended for use by athletes due to insufficient data on their efficacy and safety.
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Certain testosterone booster components may be linked to coagulation and pancreatic disorders.
“Certain TB components may be linked to coagulation and pancreatic disorders.[Citation11]”
From Ergogenic properties, safety evaluation and regulations of selected ingredients in testosterone booster dietary supplements (2024) · cites this paper as [11]
Quassinoids may inhibit the conversion of testosterone to estradiol by the aromatase enzyme.
“Quassinoids may inhibit the conversion of testosterone to estradiol by the aromatase enzyme”
From Ergogenic properties, safety evaluation and regulations of selected ingredients in testosterone booster dietary supplements (2024) · cites this paper as [11]
Quassinoids may increase the release rate of free testosterone from sex-hormone-binding-globulin (SHBG), thereby increasing testosterone levels.
“as well as increase the release rate of “free” testosterone from sex-hormone-binding-globulin (SHBG), thereby increasing testosterone levels.[Citation11,Citation81]”
From Ergogenic properties, safety evaluation and regulations of selected ingredients in testosterone booster dietary supplements (2024) · cites this paper as [11]
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Cites
Testosterone dose-response relationships in healthy young men
Bhasin, S., Woodhouse, L., Casaburi, R., Singh, A. B., Bhasin, D., Berman, N., Chen, X., Yarasheski, K. E., Magliano, L., Dzekov, C., et al. (2001) · American Journal of Physiology-Endocrinology and Metabolism · doi:10.1152/ajpendo.2001.281.6.e1172 · Cited by 967 · see citing works
Gonadal Steroids and Body Composition, Strength, and Sexual Function in Men
Finkelstein, J. S., Lee, H., Burnett-Bowie, S.-A. M., Pallais, J. C., Yu, E. W., Borges, L. F., Jones, B. F., Barry, C. V., Wulczyn, K. E., Thomas, B. J., et al. (2013) · New England Journal of Medicine · doi:10.1056/nejmoa1206168 · Cited by 782 · see citing works
Scientific basis for the therapeutic use of Withania somnifera (ashwagandha): a review.
Mishra, L. C., Singh, B. B., & Dagenais, S. (2000) · PubMed · Cited by 776 · see citing works
Maximum Strength-Power-Performance Relationships in Collegiate Throwers
STONE, M. H., SANBORN, K., OʼBRYANT, H. S., HARTMAN, M., STONE, M. E., PROULX, C., WARD, B., & HRUBY, J. (2003) · Journal of Strength and Conditioning Research · doi:10.1519/00124278-200311000-00019 · Cited by 254 · see citing works
Lopresti, A. L., Smith, S. J., Malvi, H., & Kodgule, R. (2019) · Medicine · doi:10.1097/md.0000000000017186 · Cited by 241 · see citing works
Wankhede, S., Langade, D., Joshi, K., Sinha, S. R., & Bhattacharyya, S. (2015) · Journal of the International Society of Sports Nutrition · doi:10.1186/s12970-015-0104-9 · Cited by 168 · see citing works
Mucuna pruriens improves male fertility by its action on the hypothalamus–pituitary–gonadal axis
Shukla, K. K., Mahdi, A. A., Ahmad, M. K., Shankhwar, S. N., Rajender, S., & Jaiswar, S. P. (2008) · Fertility and Sterility · doi:10.1016/j.fertnstert.2008.09.045 · Cited by 146 · see citing works
Anabolic agents: recent strategies for their detection and protection from inadvertent doping
Geyer, H., Schänzer, W., & Thevis, M. (2014) · British Journal of Sports Medicine · doi:10.1136/bjsports-2014-093526 · Cited by 132 · see citing works
Isenmann, E., Ambrosio, G., Joseph, J. F., Mazzarino, M., de la Torre, X., Zimmer, P., Kazlauskas, R., Goebel, C., Botrè, F., Diel, P., et al. (2019) · Archives of Toxicology · doi:10.1007/s00204-019-02490-x · Cited by 127 · cited 1× · see citing works
“For example, the steroidlike substance ecdysterone [59], which is present in some TB, is already on the Monitoring list, and some authors demand to prohibit ecdysterone on the basis of single studies conducted on animals and healthy volunteers [60,61].”
BackgroundNaghii, M. R., Mofid, M., Asgari, A. R., Hedayati, M., & DANESHPOUR, M. S. (2010) · Journal of Trace Elements in Medicine and Biology · doi:10.1016/j.jtemb.2010.10.001 · Cited by 122 · see citing works
Tambi, M. I. B. M., Imran, M. K., & Henkel, R. R. (2012) · Andrologia · doi:10.1111/j.1439-0272.2011.01168.x · Cited by 120 · see citing works
Lopresti, A. L., Drummond, P. D., & Smith, S. J. (2019) · American Journal of Men s Health · doi:10.1177/1557988319835985 · Cited by 110 · see citing works
Naghii, M. R., & Samman, S. (1997) · Biological Trace Element Research · doi:10.1007/bf02785299 · Cited by 105 · see citing works
Sandhu, J. S., Shah, B. N., Shenoy, S., Chauhan, S., Lavekar, G. S., & Padhi, M. M. (2010) · International Journal of Ayurveda Research · doi:10.4103/0974-7788.72485 · Cited by 105 · see citing works
Low, B., Choi, S. B., Wahab, H. A., Das, P. K., & Chan, K. (2013) · Journal of Ethnopharmacology · doi:10.1016/j.jep.2013.06.023 · Cited by 97 · see citing works
Ecdysteroids: A novel class of anabolic agents?
Parr, M., Botrè, F., Naß, A., Hengevoss, J., Diel, P., & Wolber, G. (2014) · Biology of Sport · doi:10.5604/20831862.1144420 · Cited by 95 · cited 1× · see citing works
“For example, the steroidlike substance ecdysterone [59], which is present in some TB, is already on the Monitoring list, and some authors demand to prohibit ecdysterone on the basis of single studies conducted on animals and healthy volunteers [60,61].”
BackgroundZając, A., Poprzęcki, S., Żebrowska, A., Chalimoniuk, M., & Langfort, J. (2010) · The Journal of Strength and Conditioning Research · doi:10.1519/jsc.0b013e3181d321ff · Cited by 85 · see citing works
Androgenic Responses to Resistance Exercise
Kraemer, W. J., Spiering, B. A., Volek, J. S., Ratamess, N. A., Sharman, M. J., Rubin, M. R., French, D. N., SILVESTRE, R., Hatfield, D. L., Heest, J. L. V., et al. (2006) · Medicine & Science in Sports & Exercise · doi:10.1249/01.mss.0000227314.85728.35 · Cited by 83 · see citing works
Therapeutic Benefits of l-Arginine: An Umbrella Review of Meta-analyses
McRae, M. P. (2016) · Journal of Chiropractic Medicine · doi:10.1016/j.jcm.2016.06.002 · Cited by 83 · see citing works
Talbott, S., Talbott, J. A., George, A. A., & Pugh, M. (2013) · Journal of the International Society of Sports Nutrition · doi:10.1186/1550-2783-10-28 · Cited by 82 · see citing works
Abel, T., Knechtle, B., Perret, C., Eser, P., von Arx, P., & Knecht, H. (2005) · International Journal of Sports Medicine · doi:10.1055/s-2004-821111 · Cited by 79 · see citing works
Insights into Supplements with Tribulus Terrestris used by Athletes
Pokrywka, A., Obmiński, Z., Malczewska‐Lenczowska, J., Fijatek, Z., Turek‐Lepa, E., & Grucza, R. (2014) · Journal of Human Kinetics · doi:10.2478/hukin-2014-0037 · Cited by 76 · see citing works
Rao, A., Steels, E., Inder, W. J., Abraham, S. F., & Vitetta, L. (2016) · The Aging Male · doi:10.3109/13685538.2015.1135323 · Cited by 76 · see citing works
Strauch, G., Perles, P., Vergult, G., Gabriel, M., Gibelin, B., Cummings, S. J., Malbecq, W., & Malice, M. (1994) · European Urology · doi:10.1159/000475388 · Cited by 75 · see citing works
El‐Bayoumy, K., Richie, J. P., Boyiri, T., Komninou, D., Prokopczyk, B., Trushin, N., Kleinman, W. A., Cox, J., Pittman, B. P., & Colosimo, S. (2002) · PubMed · Cited by 69 · see citing works
Wankhede, S., Mohan, V., & Thakurdesai, P. A. (2015) · Journal of sport and health science/Journal of Sport and Health Science · doi:10.1016/j.jshs.2014.09.005 · Cited by 67 · see citing works
Effects of L-arginine supplementation on exercise metabolism
McConell, G. K. (2006) · Current Opinion in Clinical Nutrition & Metabolic Care · doi:10.1097/mco.0b013e32801162fa · Cited by 64 · see citing works
Cinar, V., Polat, Y., Baltaci, A. K., & Mogulkoc, R. (2011) · Biological Trace Element Research · doi:10.1007/s12011-010-8676-3 · Cited by 62 · see citing works
Henkel, R., Wang, R., Bassett, S. H., Chen, T., Liu, N., Zhu, Y., & Tambi, M. I. B. M. (2013) · Phytotherapy Research · doi:10.1002/ptr.5017 · Cited by 55 · see citing works
Examining the Effects of Herbs on Testosterone Concentrations in Men: A Systematic Review
Smith, S. J., Lopresti, A. L., Teo, S. Y. M., & Fairchild, T. J. (2020) · Advances in Nutrition · doi:10.1093/advances/nmaa134 · Cited by 53 · see citing works
Bioactive Constituents from the Roots of Eurycoma longifolia
Ruan, J., Li, Z., Zhang, Y., Chen, Y., Liu, M., Han, L., Zhang, Y., & Wang, T. (2019) · Molecules · doi:10.3390/molecules24173157 · Cited by 51 · see citing works
Shafiei Neek, L., Gaeini, A. A., & Choobineh, S. (2011) · Biological Trace Element Research · doi:10.1007/s12011-011-9138-2 · Cited by 48 · see citing works
Maheshwari, A., Verma, N., Swaroop, A., Bagchi, M., Preuss, H. G., Tiwari, K., & Bagchi, D. (2017) · International Journal of Medical Sciences · doi:10.7150/ijms.17256 · Cited by 47 · see citing works
Sudeep, H. V., Thomas, J. V., & Shyamprasad, K. (2020) · BMC Urology · doi:10.1186/s12894-020-00648-9 · Cited by 47 · see citing works
Effects of a Purported Aromatase and 5 α-Reductase Inhibitor on Hormone Profiles in College-Age Men
Wilborn, C., Taylor, L. W., Poole, C. N., Foster, C. A., Willoughby, D. S., & Kreider, R. B. (2010) · International Journal of Sport Nutrition and Exercise Metabolism · doi:10.1123/ijsnem.20.6.457 · Cited by 46 · see citing works
Treating exercise-associated low testosterone and its related symptoms
Hooper, D., Tenforde, A., & Hackney, A. C. (2018) · Physician and sportsmedicine · doi:10.1080/00913847.2018.1507234 · Cited by 45 · see citing works
Ferrando, A. A., & Green, N. R. (1993) · International Journal of Sport Nutrition · doi:10.1123/ijsn.3.2.140 · Cited by 41 · see citing works
Clinical evaluation of purified Shilajit on testosterone levels in healthy volunteers
Pandit, S., Biswas, S., Jana, U., De, R. K., Mukhopadhyay, S. C., & Biswas, T. K. (2015) · Andrologia · doi:10.1111/and.12482 · Cited by 39 · see citing works
Hsu, M. (2011) · The Chinese Journal of Physiology · doi:10.4077/cjp.2011.amk075 · Cited by 37 · see citing works
Testosterone Imposters: An Analysis of Popular Online Testosterone Boosting Supplements
Balasubramanian, A., Thirumavalavan, N., Srivatsav, A., Yu, J., Lipshultz, L. I., & Pastuszak, A. W. (2019) · The Journal of Sexual Medicine · doi:10.1016/j.jsxm.2018.12.008 · Cited by 32 · see citing works
A Possible Case of Saw Palmetto–Induced Pancreatitis
Wargo, K. A., Allman, E., & Ibrahim, F. (2010) · Southern Medical Journal · doi:10.1097/smj.0b013e3181e1e3ee · Cited by 30 · see citing works
Leitão, A. E., Vieira, M. C. D. S., Pelegrini, A., da Silva, E. L., & Guimarães, A. C. D. A. (2021) · Maturitas · doi:10.1016/j.maturitas.2020.12.002 · Cited by 30 · see citing works
Mansoori, A., Hosseini, S., Zilaee, M., Hormoznejad, R., & Fathi, M. (2020) · Phytotherapy Research · doi:10.1002/ptr.6627 · Cited by 29 · see citing works
Bezuglov, E., Talibov, O., Butovskiy, M., Khaitin, V., Achkasov, E., Waśkiewicz, Z., & Lazarev, A. (2021) · Asian Journal of Sports Medicine · doi:10.5812/asjsm.110753 · Cited by 26 · see citing works
Self-citationClemesha, C. G., Thaker, H., & Samplaski, M. K. (2019) · The World Journal of Men s Health · doi:10.5534/wjmh.190043 · Cited by 21 · see citing works
de Andrade, W. B., Jacinto, J. L., da Silva, D. K., Roveratti, M. C., Estoche, J. M., Oliveira, D. B., Balvedi, M. C. W., da Silva, R. A., & Aguiar, A. F. (2018) · Applied Physiology, Nutrition, and Metabolism · doi:10.1139/apnm-2017-0594 · Cited by 20 · see citing works
Do antioxidants improve serum sex hormones and total motile sperm count in idiopathic infertile men?
Saylam, B., & Çayan, S. (2020) · Urology Research and Practice · doi:10.5152/tud.2020.20296 · Cited by 20 · see citing works
Advanced Methods for the Analysis of Testosterone
Gugoaşă, L. A., & Staden, R. S. (2017) · Current Medicinal Chemistry · doi:10.2174/0929867324666170724102602 · Cited by 19 · see citing works
Several effects of boron are induced by uncoupling steroid hormones from their transporters in blood
Bello, M., Guadarrama-García, C., Velasco-Silveyra, L. M., Farfán‐García, E. D., & Soriano-Ursua, M. A. (2018) · Medical Hypotheses · doi:10.1016/j.mehy.2018.06.024 · Cited by 18 · see citing works
Pulmonary Embolism Secondary to Testosterone-Enhancing Herbal Supplement Use
Nguyen, S. M., Ko, N. K., Sattar, A., İpek, E. G., & Ali, S. K. (2017) · Cureus · doi:10.7759/cureus.1545 · Cited by 16 · see citing works
Rao, A., Mallard, A. R., & Grant, R. (2020) · Translational Sports Medicine · doi:10.1002/tsm2.153 · Cited by 13 · see citing works
The effect of <i>Eurycoma Longifolia</i> on the regulation of reproductive hormones in young males
Chan, K. Q., Stewart, C., Chester, N., Hamzah, S. H., & Yusof, A. (2021) · Andrologia · doi:10.1111/and.14001 · Cited by 12 · see citing works
Thakurdesai, P. A., Mokashi, M., Mokashi, R. S., & Mohan, V. (2014) · Asian Journal of Pharmaceutical and Clinical Research · Cited by 11 · see citing works
Chen, C. K., Ooi, F. K., Kasim, N. A. A., & Asari, M. A. (2019) · International Journal of Preventive Medicine · doi:10.4103/ijpvm.ijpvm_404_17 · Cited by 11 · see citing works
Medicinal plants: conception / contraception.
Chaing, H. S., Merino-chavez, G., Yang, L., Wang, F. N., & Hafez, E. S. E. (1994) · PubMed · Cited by 10 · see citing works
A Possible Association of Diindolylmethane with Pulmonary Embolism and Deep Venous Thrombosis
Bui, P. V., Moualla, M., & Upson, D. J. (2016) · Case Reports in Medicine · doi:10.1155/2016/7527098 · Cited by 8 · see citing works
Effect of testosterone boosters on body functions: Case report.
Almaiman, A. A. (2018) · PubMed Central · Cited by 7 · see citing works
El‐Bayoumy, K., Richie, J. P., Boyiri, T., Komninou, D., Prokopczyk, B., Trushin, N., Kleinman, W. A., Cox, J., Pittman, B. P., & Colosimo, S. (2002) · Cancer Epidemiology and Prevention Biomarkers · Cited by 4 · see citing works
Leitão, A. E., Vieira, M. D. C. S., Gomes, D. A., Boing, L., Pelegrini, A., Luiz, E., & Guimarães, A. C. D. A. (2021) · Complementary Therapies in Clinical Practice · doi:10.1016/j.ctcp.2020.101301 · Cited by 3 · see citing works
Moosakhani, A., Choobineh, S., & Soori, R. (2018) · Gazzetta Medica Italiana Archivio per le Scienze Mediche · doi:10.23736/s0393-3660.17.03497-0 · Cited by 3 · see citing works
Santos (2000) · doi:10.1002/1099-1573(200006)14:4
Flagged first, then by citations
Research works printed but not linked: 1
- [9]9. Koumanov, F.; Bozadjieva, E.; Andreeva, M.; Platonva, E.; Ankov, V. Clinical Trial of Tribestan. Exp. Med. 1982 , 4 , 211-215.
Cited by
Sorted by citations
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Nalbantova, V., Benbassat, N., & Delattre, C. (2024) · Polysaccharides · doi:10.3390/polysaccharides5030030 · Cited by 20 · see citing works
McDaid, B., Wardenaar, F. C., Woodside, J. V., Neville, C. E., Tobin, D., Madigan, S. M., & Nugent, A. P. (2023) · International Journal of Environmental Research and Public Health · doi:10.3390/ijerph20136244 · Cited by 10 · see citing works
Skrzypiec‐Spring, M., Pokrywka, A., Kuliczkowska-Płaksej, J., Szeląg, A., & Bolanowski, M. (2024) · Advances in Clinical and Experimental Medicine · doi:10.17219/acem/185743 · Cited by 8 · see citing works
Nekooei, S., Ghaedi, M., Baezzat, M. R., Tashkhourian, J., & Sillanpää, M. E. T. (2025) · Analytical Biochemistry · doi:10.1016/j.ab.2025.115827 · Cited by 7 · see citing works
Yan, J. (2024) · Matéria (Rio de Janeiro) · doi:10.1590/1517-7076-rmat-2024-0177 · Cited by 5 · see citing works
Wahab, M. S. A., Hamid, N. N. A., Yassen, A. O., Naim, M. J., Ahamad, J., Zulkifli, N. W., Ismail, F., Zulkifli, M. H., Goh, K. W., & Ming, L. C. (2022) · International Journal of Environmental Research and Public Health · doi:10.3390/ijerph191911853 · Cited by 5 · see citing works
Jędrejko, K., Lazarev, A., Jędrejko, M., & Muszyńska, B. (2024) · Food Reviews International · doi:10.1080/87559129.2023.2238055 · Cited by 4 · see citing works
Self-citationSPORCULAR TARAFINDAN KULLANILAN DOĞAL KAYNAKLI ERGOJENİK DESTEKLER
BAYIR, E., Cebe, G. E., & Ozturk, B. G. (2023) · Ankara Universitesi Eczacilik Fakultesi Dergisi · doi:10.33483/jfpau.1316067 · Cited by 4 · see citing works
Testosterone-Optimizing Strategies in Athletes
Lazarev, A. M., Pujalte, G. G. A., Philibert, C., Meek, S., Broderick, G. A., Zapp, D. G., Mayo, M. R., & Hackney, A. C. (2026) · Sports Health A Multidisciplinary Approach · doi:10.1177/19417381251411933 · Cited by 3 · see citing works
Self-citationThe Effect of Tongkat Ali Supplementation on Body Composition in Exercise-Trained Males and Females
António, J., Evans, C., Pereira, F., Thakkar, H., Miriyala, V., Rocanelli, R., Castillo, C., Andal, A., Rojas, J., Santana, J. C., et al. (2024) · Applied Sciences · doi:10.3390/app14114372 · Cited by 2 · see citing works
Lak, M., Goudarzi, K., & Shahrbaf, M. A. (2022) · Asian Journal of Sports Medicine · doi:10.5812/asjsm-120161
Everett, J., Minehan, M., Praet, S., & McKune, A. J. (2026) · Nutrition and Health · doi:10.1177/02601060261431124
Mollahosseini, M., Rahimi, M. H., Hosseini‐Marnani, E., Yazdanpanah, Z., Mozaffari–Khosravi, H., & Hosseinzadeh, M. (2026) · فصلنامه علوم پزشکی دانشگاه آزاد اسلامی واحد پزشکی تهران · doi:10.66224/iau.36.2.129
Analysis of androgen modulation by natural products
Sharma, K., Yakubu, J., & Pandey, A. V. (2026) · Pharmacological Research · doi:10.1016/j.phrs.2026.108377
- Authors
- Lazarev, A., & Bezuglov, E.
- Affiliations
- Moscow Witte University (RU)
- Sechenov University (RU)
- Corresponding author
- Lazarev, Artemii
- Venue
- Endocrines
- Publisher
- MDPI AG
- Published
- 2021-05-17
- Volume
- 2
- Issue
- 2
- Pages
- 109-120
- ISSN
- 2673-396X (ISSN-L)
- OpenAlex
- W3160001118
- Cited by
- 14
- References
- 61
- Citations by year
- 2026: 4 · 2025: 1 · 2024: 4 · 2023: 3 · 2022: 2
- FWCI
- 1.68
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Endocrines (publishedVersion, cc-by)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Topics
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Hormonal and reproductive studies
- Social Sciences › Sociology and Political Science › Doping in Sports
- Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
- Keywords
- testosterone booster, dietary supplements, athletes, testosterone, Eurycoma longifolia, Withania somnifera, fenugreek, L-arginine, L-carnitine, selenium, magnesium, Shilajit, Serenoa repens, boron, supplement safety, supplement efficacy
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