THG (Tetrahydrogestrinone)
Tetrahydrogestrinone ("The Clear"), designer AAS synthesized by Patrick Arnold in 2002 for BALCO Conte. Don Catlin (UCLA) discovered it from an anonymous used-syringe sample in 2003. Marion Jones, Tim Montgomery, Barry Bonds scandal. Today USA Schedule III, never an Rx.
WHAT IS THG (TETRAHYDROGESTRINONE)?
Detailed overview
THG (Tetrahydrogestrinone) is a designer anabolic steroid: a tetrahydro-Gestrinone analog synthesized in 2002 by Patrick Arnold (inventor of 1-Andro) for Victor Conte, owner of BALCO Laboratories (Burlingame, CA), for the doping of athlete clients. BALCO marketed it under the code name "The Clear"; as a designer it was specifically created to NOT BE DETECTABLE by pre-2003 WADA-accredited assays. In June 2003 an anonymous whistleblower (Trevor Graham, a coach) sent a used THG syringe to Don Catlin's lab (UCLA Olympic Analytical Laboratory), from which Catlin identified the parent compound by LC-MS/MS. The 2003-2007 grand jury investigation that followed implicated 6+ Olympic-World Championship athletes: Marion Jones (5 Olympic medals stripped 2007), Tim Montgomery (100m WR 9.78s stripped), Barry Bonds (MLB perjury indictment), Bill Romanowski (NFL), Trevor Graham coach (lifetime ban). In 2004 the US Congress Anabolic Steroid Control Act amendment placed it under Schedule III. Chemically it is a tetrahydro-reduced derivative of Gestrinone (an existing progestin/anti-progestin) – high AR affinity + progestogenic activity dual action. Never an Rx, exclusively a BALCO-designed designer steroid. WADA-banned year-round.
Mechanism
AR agonist + progesterone-receptor agonist, designer non-aromatizing
Anabolic:Androgenic
Extrapolated ~150:75 (no clinical trial)
Half-life
~16-24 hours (extrapolated from gestrinone)
Onset
12-24 h (sublingual oil drop typical BALCO protocol)
Legal status
Schedule III (USA 2004), never an Rx, WADA-banned
Data console
Lab data
Safety
Side effects, stop signs, contraindications
Side effects · 7
- Classic androgenic effects (acne, oily skin, scalp hair loss in men) from strong AR agonism – expected for the AAS class, though no human THG data exist.
- HPG-axis (HPTA) suppression: shutdown of endogenous testosterone, LH and FSH, with low libido and testicular atrophy, potentially requiring PCT.
- Progesterone-receptor (PR) agonism: progestogenic effects (possible prolactin elevation, gyno risk despite the compound NOT aromatizing) – warranting prolactin monitoring.
- Unfavorable lipid shift (HDL reduction) and potential cardiovascular strain typical of anabolic steroids – no THG-specific clinical data.
- Disruption of hepatic glucocorticoid signalling: in vitro the THG binds non-selectively and affects glucocorticoid signalling in the liver, with potential metabolic impact (Friedel/Diel 2006, PMID 16356667).
- Psychological effects from individual case reports (Marion Jones grand jury testimony): anxiety, sleep disturbance – uncontrolled, anecdotal data only.
- UNKNOWN long-term safety profile: THG was NEVER studied in humans in controlled trials, so the true side-effect spectrum, frequency and severity are unknown.
Contraindications · 7
- Women, especially during or planning pregnancy: strong androgenic + progestogenic activity can cause virilization and fetal harm (teratogenic risk).
- Any WADA / drug-tested athlete: THG has been detectable since 2003 and is banned year-round (WADA S1.1.a); its designer 'undetectable' purpose is gone.
- Fertility preservation / planned fatherhood: HPG-axis suppression and progestogenic activity impair spermatogenesis and fertility.
- Pre-existing cardiovascular disease or adverse lipids: the HDL-lowering and cardiovascular-strain profile of AAS is a relative contraindication.
- Hormone-sensitive (androgen- or progesterone-receptor-positive) cancers, e.g. suspected prostate cancer: AR/PR agonism may stimulate tumor growth.
- Hyperprolactinemia or prolactin-sensitive conditions: PR activity can raise prolactin and worsen the existing state.
- General caution: NO human clinical safety data exist, so any human use of THG is unjustified and not recommended – historical/educational interest only.
Related Performance Compounds
Same therapeutic category
Studies
Related research and clinical findings
Tetrahydrogestrinone: discovery, synthesis, and detection in urine.
Catlin DH, Sekera MH, Ahrens BD, Starcevic B, Chang YC, Hatton CK
Tetrahydrogestrinone is a potent but unselective binding steroid and affects glucocorticoid signalling in the liver.
Friedel A, Geyer H, Kamber M, Laudenbach-Leschowsky U, Schänzer W, Thevis M, Vollmer G, Zierau O, Diel P
Tetrahydrogestrinone is a potent androgen and progestin.
Death AK, McGrath KC, Kazlauskas R, Handelsman DJ
Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement
Pope HG Jr, Wood RI, Rogol A, Nyberg F, Bowers L, Bhasin S.
Effects of androgenic-anabolic steroids in athletes.
Hartgens F, Kuipers H
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The information here is for educational and scientific purposes only. Performance-enhancing compounds (AAS, prohormones, stimulants, doping agents) are illegal without prescription in Hungary and most of the EU, and carry serious health and legal risks. WADA bans them in competitive sport. This is NOT a usage guide, and we do not encourage any illegal use. If you do use them, medical supervision and regular bloodwork are ESSENTIAL. Severe endocrine, cardiovascular, hepatic and psychiatric side effects are possible.