Tetrahydrogestrinone (THG)

Tetrahydrogestrinone (THG) is a synthetic, orally active anabolic-androgenic steroid (AAS) that was never marketed for medical use.

Here is a detailed breakdown of the information requested:

1. Tetrahydrogestrinone (THG) (explain in detail/different name)

• Detailed Explanation: THG is a "designer steroid," meaning it was specifically synthesized to evade detection by standard doping tests at the time of its creation. It is a modification of the steroid gestrinone, in which an ethynyl group is hydrogenated into an ethyl group. This structural change results in a compound with extremely high potency for the androgen and progesterone receptors. It was developed in secret by Patrick Arnold for the Bay Area Laboratory Co-operative (BALCO) and became known during the high-profile doping scandal in the early 2000s, often nicknamed "The Clear" in athletic circles.

• Other Names:

  • The Clear (nickname)

  • THG

  • 17$\alpha$-Ethyl-18-methylestra-4,9,11-trien-17$\beta$-ol-3-one (IUPAC name)

  • 17$\alpha$-Ethyl-18-methyl-δ9,11-19-nortestosterone

2. Side Effects and Benefits

Note: THG was never medically approved, so these "benefits" are based on its intended use for performance enhancement and not medical application.

3. Pros and Cons

4. Dosage and Frequency

There is no standardized or medically recommended dosage for THG as it was never a licensed pharmaceutical product. Information on illicit usage patterns is anecdotal and unverified.

• One of its developers claimed that due to its potency, "just a couple of drops under the tongue" was a sufficient dose for illicit use, suggesting a very low dosage used sublingually (under the tongue) or via intramuscular injection.

• The actual dosage and frequency used by athletes are not publicly documented or scientifically established.

5. Half-Life and Detection Time

• Half-Life: The precise biological half-life of THG is not well-documented in medical literature since it was not a commercial drug. Based on it being an orally active steroid, its parent compound likely has a relatively short half-life, possibly in the range of hours to a few days.

• Detection Time (Urine): While the original compound was designed to be undetectable, advanced testing methods now focus on its metabolites. The detection time is highly variable based on dosage, duration of use, individual metabolism, and testing methods. Estimates for its unique metabolites are not consistently published, but its structure suggests a detection window likely in the range of several weeks to a few months in urine, similar to other long-acting anabolic steroid metabolites.

6. Sterogenic, Progestronic, and Prolactin Affects

• Sterogenic (Estrogenic): THG has been shown to have no estrogenic activity; it does not bind significantly to the estrogen receptor and does not directly aromatize into estrogen.

• Progestronic: THG is a highly potent agonist of the progesterone receptor (PR), meaning it strongly activates this receptor. This progestogenic activity contributes to its hormonal effects.

• Prolactin: Direct effects on prolactin levels are not clearly established in published studies, but many progestogenic/nandrolone-derived steroids can indirectly affect prolactin, sometimes leading to elevated levels. However, its primary mechanisms involve the androgen and progesterone receptors. THG also binds to the Glucocorticoid Receptor (GR) and Mineralocorticoid Receptor (MR).

7. Anabolic Androgenic Ratio

The Anabolic:Androgenic ratio compares a substance's muscle-building (anabolic) effect to its masculinizing (androgenic) effect, often using testosterone (100:100 or 1:1) as a reference.

• THG Anabolic:Androgenic Ratio: A specific, definitively published number for the Anabolic:Androgenic ratio in humans is not available. However, in vivo studies in rats have shown that THG possesses anabolic and androgenic properties. One study suggested that while THG is more potent than dihydrotestosterone (DHT) in binding to the androgen receptor in vitro, in vivo in rats it possessed only 20% of the potency of DHT in stimulating the weight of androgen-sensitive tissues like the prostate and seminal vesicle (androgenic activity) and the levator ani muscle (anabolic activity). This suggests a favorable anabolic effect relative to its androgenic side effects, but a precise ratio like X:Y is not verifiable with the current public scientific literature.

• Potency Comparison: In terms of receptor binding potency, THG is reported to be about 10 times more potent than comparison drugs like nandrolone or trenbolone at the androgen and progesterone receptors.