Tetrahydrogestrinone (THG)

March 22, 2017


Tetrahydrogestrinone (THG)

Natural Standard Monograph, Copyright © 2013 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Related Terms

  • Anabolic steroids, Anabolic Steroids Act (ASA), blood doping, controlled substances, Controlled Substances Act (CSA), designer steroid, gestrinone, illegal drugs, male hormones, prohormones, schedule III, steroids, testosterone, The clear, THG, trenbolone.


  • In 1991, Congress classified anabolic steroids as schedule III drugs under the Controlled Substances Act (CSA). This legislation was passed in response to a growing illegal market and due to concerns about the possible harmful long-term effects of steroid use.

  • Anabolic steroids are synthetic male sex hormones, collectively known as androgens. Although banned in sporting events, athletes frequently take these hormones to build more muscle and provide enhanced endurance. Some anabolic-androgenic steroids, such as methyltestosterone, oxandrolone, and oxymetholone have approved medical uses, but tetrahydrogestrinone (THG) does not.

  • THG is an anabolic steroid that was developed in 2001 by Patrick Arnold for Bay Area Laboratory Co-operative (Balco), a San Francisco-based laboratory. It is commonly referred to as a "designer drug" because it is specifically formulated to be undetectable in drug tests.

  • Soon after its development, athletes began using THG to boost their athletic performance.

  • Athletes are regularly screened for such illegal methods in professional sports and the Olympics. However, since THG was not detectable until 2003, some world-famous athletes, such as the track-and-field athlete Marion Jones, have used THG to enhance athletic performance.

  • Anabolic steroids intended for medicinal use are prescribed only after trying other classes of medications due to the side effects associated with their use. The use of anabolic steroids for a purpose other than that prescribed to a patient is strictly illegal in the United States.

  • The U.S. Food and Drug Administration (FDA) has stated that THG may pose a substantial risk to the public health, and it remains unapproved.


  • General: Anabolic steroids such as tetrahydrogestrinone (THG) are taken by mouth or injected. Often, athletes take multiple anabolic steroids simultaneously, using one of two methods: cycling or stacking. Both of these methods are considered equally dangerous.

  • Cycling: Athletes take multiple types of high-dose steroids simultaneously in cycles of weeks or months and then abstain from their use for a washout period before beginning the cycle again. This pattern is thought to maximize the benefits of the steroids by preventing the body from adjusting to and thus weakening the effects of the drugs.

  • Stacking: Individuals take multiple brands or types of anabolic steroids simultaneously in the belief that such a dosing pattern may have more of an effect than any one drug taken alone. While this pattern is thought to reduce the short-time side effects of anabolic steroid abuse (such as acne and abnormal facial hair growth), it does not minimize any of the often irreversible long-term side effects, such as infertility.

  • The use of anabolic steroids for a purpose other than that prescribed to a patient by a medical professional is strictly illegal in the United States.


  • Tetrahydrogestrinone (THG) is an anabolic steroid that helps to promote muscle growth and allows athletes to train harder. It works like testosterone, a hormone that may result in a deepened voice and increased body-hair growth in female users. It works on the androgen and progesterone receptors, but not the estrogen receptor.

  • Although THG has been used primarily as a performance enhancer in athletes, there are ongoing studies of its use in treating muscle loss in the elderly and those with chronic disease states such as AIDS. More evidence is needed to support its effectiveness in improving physical function and quality of life in these populations.


  • A qualified health care provider should be consulted before making decisions about therapies and/or health conditions.

  • Anabolic steroids have been linked to a number of health conditions. These include acne, liver tumors, cancer, high blood pressure, increases in "bad" (LDL) cholesterol, and kidney tumors. According to scientific evidence, THG may also result in both male and female infertility. Anabolic steroids may have significant effects on certain groups of people.

  • In women, facial-hair growth, male-pattern baldness, menstrual irregularities, enlargement of the clitoris, and a deepened voice have been reported.

  • Some evidence suggests that THG use may result in effects different from those seen with other anabolic steroids, including weight loss and weakening of the immune system.

Author Information

  • This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).


Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

  1. Catlin DH, Sekera MH, Ahrens BD, et al. Tetrahydrogestrinone: discovery, synthesis, and detection in urine. Rapid Commun Mass Spectrom. 2004;18(12):1245-49. View Abstract

  2. Death AK, McGrath KC, Kazlauskas R, et al. Tetrahydrogestrinone is a potent androgen and progestin. J Clin Endocrinol Metab. 2004 May;89(5):2498-500. View Abstract

  3. Friedel A, Geyer H, Kamber, et al. Tetrahydrogestrinone is a potent but unselective binding steroid and affects glucocorticoid signalling in the liver. Toxicol Lett. 2006 Jun 20;164(1):16-23. View Abstract

  4. Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol. 2008 Jun;154(3):502-21. View Abstract

  5. Labrie F, Luu-The V, Calvo E, et al. Tetrahydrogestrinone induces a genomic signature typical of a potent anabolic steroid. J Endocrinol. 2005 Feb;184(2):427-33. View Abstract

  6. Machnik M, Gerlach M, Kietzmann M, et al. Detection and pharmacokinetics of tetrahydrogestrinone in horses. J Vet Pharmacol Ther. 2009 Apr;32(2):197-202. View Abstract

  7. Natural Standard: The Authority on Integrative Medicine. www.naturalstandard.com

Copyright © 2013 Natural Standard (www.naturalstandard.com)

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.


March 22, 2017