science

Tetrahydrogestrinone

Tetrahydrogestrinone is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tetrahydrogestrinone rather than just read about it. In short: Tetrahydrogestrinone (THG), known by the nickname The Clear, is a synthetic and orally active anabolic–androgenic steroid (AAS) which was never marketed for medical use. It was developed by Patrick Arnold and was used by a number of high-profile athletes such as Barry Bonds and Dwain Chambers.

Key takeaways

Tetrahydrogestrinone belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tetrahydrogestrinone to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tetrahydrogestrinone from memory before moving on to harder problems.

Reference excerpt

Tetrahydrogestrinone (THG), known by the nickname The Clear, is a synthetic and orally active anabolic–androgenic steroid (AAS) which was never marketed for medical use. It was developed by Patrick Arnold and was used by a number of high-profile athletes such as Barry Bonds and Dwain Chambers.

Non-medical uses THG was developed completely in secret by Patrick Arnold as a designer drug, on the basis that doping testers would be unlikely to detect a totally new compound. Arnold developed a chemical similar to two obscure steroids marketed by BALCO, norbolethone and desoxymethyltestosterone, which had been reported in scientific literature but never entered mass production, and the banned anabolic steroids trenbolone and gestrinone, the latter of which was used to synthesize it. In 2003, whistleblower Trevor Graham passed a spent syringe containing a small amount of the drug to the United States Anti-Doping Agency. This was then transferred to the research group of pharmacologist Don Catlin, who identified the drug using mass spectrometry techniques and gave it its present name. THG has never been fully tested for safety and has never entered legitimate medical use, although some studies have been made of its properties. A synthesis was devised to ensure a source of material for comparison and it was scheduled by the Food and Drug Administration (FDA) in 2005. Concerns have also been raised about its potential use in animals such as in horse-racing.

Side effects

Side effects from prolonged use are likely to include infertility in both men and women, as well as other steroid side effects such as acne and hirsutism. Unlike most other anabolic steroids, THG also binds with high affinity to the glucocorticoid receptor, and while this effect may cause additional weight loss, it is also likely to cause additional side effects such as immunosuppression that are not seen with most other steroids.

Pharmacology

Pharmacodynamics THG is a highly potent agonist of the androgen and progesterone receptors, around 10 times more potent than the comparison drugs nandrolone or trenbolone, but with no estrogenic activity. It has been found to bind to the androgen receptor with similar affinity to dihydrotestosterone and produces growth of muscle tissue. According to Patrick Arnold, due to the drug's potency, he never had to supply significant quantities to BALCO, because "just a couple of drops under the tongue" were a sufficient dose. When THG reaches the nucleus of a cell, it binds to the androgen receptor at the ligand-binding pocket. Here it changes the expression of a variety of genes, turning on several anabolic and androgenic functions. It is the ligand's structure which determines the number of interactions that can take place with the human androgen receptor ligand-binding domain. Even minor modifications in the ligand's structure have a great impact on the strength of the interactions this ligand has with the androgen receptor. THG, possessing a high affinity, establishes more van der Waals contacts with the receptor than with many other steroids. It is this higher affinity and specific geometry of THG which makes these interactions with the androgen receptor so strong, resulting in THG's potency.

Chemistry

THG, also known as 17α-ethyl-18-methyl-δ9,11-19-nortestosterone or as 17α-ethyl-18-methylestra-4,9,11-trien-17β-ol-3-one, is a synthetic estrane steroid and a 17α-alkylated derivative of nandrolone (19-nortestosterone). It is a modification of gestrinone (17α-ethynyl-18-methyl-19-nor-δ9,11-testosterone) in which the ethynyl group has been hydrogenated into an ethyl group, thereby converting the steroid from a norethisterone (17α-ethynyl-19-nortestosterone) derivative with weak AR activity into a norethandrolone (17α-ethyl-19-nortestosterone) derivative with powerful AR activity. THG is closely related to RU-2309 (the 17α-methyl variant), trenbolone (δ9,11-19-nortestosterone), metribolone (17α-methyl-δ9,11-19-nortestosterone), and norboletone (17α-ethyl-18-methyl-19-nortestosterone).

History For a time, THG was considered the drug of choice for safe and "invisible" world record breaking in athletics, being used by several high-profile gold medal winners such as the sprinter Marion Jones, who resigned from her athletic career in 2007 after admitting to using THG prior to the 2000 Sydney Olympics, where she had won three gold medals. It has also been used by formerly banned British athlete Dwain Chambers, Major League Baseball left fielder Barry Bonds, and Major League Baseball first baseman Jason Giambi. THG was developed by Patrick Arnold for the Bay Area Laboratory Co-operative (BALCO), which claimed to be a nutritional supplement company. The company manufactured the drug through palladium-charcoal catalyzed hydrogenation from gestrinone, a substance used in gynecology for treatment of endometriosis (Australian Medicines handbook 2011). In 2003, U.S. sprint coach Trevor Graham delivered a syringe containing traces of THG to the United States Anti-Doping Agency (USADA). This helped Don Catlin, MD, the founder and then-director of the UCLA Olympic Analytical Lab, to identify and develop a test for THG, the second reported designer anabolic steroid.

References

External links The identity of the whistle-blowing coach "This Is Very Clever Chemistry" from The Washington Post, December 4, 2004 Audio interview "ANABOLIC STEROID CHEMISTRY with Patrick Arnold" on Hamilton Morris YouTube

Illustrations

Worked examples

Example 1 — a first encounter with Tetrahydrogestrinone

Start with the simplest possible case. Write down what Tetrahydrogestrinone claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tetrahydrogestrinone before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tetrahydrogestrinone ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tetrahydrogestrinone

In research: Tetrahydrogestrinone appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tetrahydrogestrinone in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tetrahydrogestrinone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alcohols, Androgens, Designer drugs, so understanding it makes those chapters shorter.
In everyday life: Look for Tetrahydrogestrinone outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tetrahydrogestrinone in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tetrahydrogestrinone means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tetrahydrogestrinone out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tetrahydrogestrinone in simple terms?

Why does Tetrahydrogestrinone matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tetrahydrogestrinone?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tetrahydrogestrinone.