View Full Version : Tetrahydrogestrinone~The Clear

01-09-2010, 10:40 AM
The Clear


18a-homo- pregna-4,9,11-trien-17β-ol-3- one
Molecular Weight (base): 312.46
Formula (base): C12 H28 O2
Melting Point: Unknown
Effective Dose (Men):
Active life: Undefined (~24 hours?)
Detection Time: Unclear
Anabolic: Androgenic ratio: Undefined

Unlike most anabolic steroids (http://www.steroid.com/main.php), this one was synthesized in the last couple of years with the intent for it to be used by athletes seeking to beat sports (http://www.steroid.com/steroids-in-sports.php) doping tests. It’s actually a pretty decent anabolic (http://www.steroid.com/main.php), basically being a cross between gestrinone and trenbolone (1) Frankly, it would have likely still been beating tests and helping athletes break records, if a sample of it hadn’t been sent by Trevor Graham (2-3), a disgruntled coach, to Don Cailin of the World Anti-Doping Agency.

Although this profile is clearly meant to educate you on the chemical properties of this particular drug, no legitimate discussion of this steroid would be complete without an assessment of the major players involved in its creation, discovery, and vilification. Even it’s most common name (“The Clear”) conjures up thoughts of BALCO, Barry Bonds, Jason Giambi, Marion Jones, Tim Montgomery, Victor Conte, Don Catlin, and of course, Patrick Arnold (credited with bringing Androstendione to the supplement market, and often called the “Father of Prohormones”).

Initially, “The Clear” (THG) was developed after Victor Conte was complimented on his ZMA study on the internet, by Patrick Arnold. Subsequently, Victor e-mailed Patrick and asked if his Andro product would be detectable on drug tests. Pat responded by saying “If you wanna go that route, I know much better things…” after which the “program” was developed. The “program” of course, was the synthesis and administration of undetectable steroids to elite athletes, and the eventual recognition (after being tipped off) of that program by anti-doping authorities.

And really, the only reason anybody ever knew about the program at all (other than it was creating world champions) is because a jealous coach who was watching his athletes lose to BALCO athletes eventually mailed a sample of THG to Don Catlin. Although my interactions with Pat have been pretty much of the superficial/internet variety, I’m not against giving credit where it’s due. THG is really a very cool anabolic. In a similar vein, I find it in very poor taste that Mr.Catlin was soundly out-thought by Arnold, and refused to give him credit for creating a drug that he never would have detected had Smith not sent him a sample…saying:

“It’s hard for me to say he’s brilliant...it’s hard to call somebody who works the other side of the street brilliant…”

Then adding, talking about the steroid Pat had synthesized:

“we were absolutely blind to it”

Well, his athletes beat every drug test they were given, and he fooled the largest anti—doping agency in the world, and if you’re the head of it, then he may not be brilliant, but he’s likely much smarter than you are.

Alright, enough about the politics and back story surrounding THG. Let’s get into some specifics about what it can do, anabolic-wise.

First of all, it’s a very strong androgen as well as progestin (1), but I doubt it has much potential for bodybuilders. This seems contradictory at first, but I think that if you were to really use this stuff to gain the kind of weight that is winning bodybuilding (http://forums.steroid.com/) shows or to get as ripped as current judging standards require, you would need to take an amount of this stuff that would surely cause progesterone related side effects (http://www.steroid.com/side.php).

On a milligram for milligram basis, I would suspect it’s probably going to be very potent and maybe somewhere between 5-10mgs a day would be appropriate. The method of administration for BALCO athletes on the “program” was to take a few drops of it and allow it to be absorbed under the tongue. Personally, I would have liked to see how it performed as a nasal spray, but we will probably never have the answer to that question.

THG, which is essentially 17-alpha ethylated gestrinone, very well to the androgen receptor (like it’s parent compound) (1, 4), and likely produces many of the lipolytic (fat burning) and anabolic (muscle building) effects we typically see with such strong androgen binding, Unfortunately, it also exhibits progesteronic activity roughly 7x as potent as progesterone itself (making it literally dozens of times a more potent progestin than nandrolone). (1) Although it has no ability to aromatize (4) (and I suspect is 5a-reducatse resistant), because of it’s ability to act as a very powerful progestin, I would suspect that it’s ability to inhibit the natural production of testosterone would be literally off the charts. It’s also possible that its powerful ability to stimulate the progesterone receptor was helping athletes “feel” better and less beat up from their workouts.

I still can’t even imagine how badly it must have shut down natural testosterone production, though I would speculate that it’s probably staggeringly suppressive. Perhaps this is the reason it was orally administered, or perhaps this is the reason it was often administered in conjunction with “the Cream” which was a testosterone based transdermal product.

I don’t know what kind of street value something like this would actually have, or even if it’s ever been attempted by an underground lab, but it’s unlikely to be widely available any time in the near future.


1. Death AK, McGrath KC, Kazlauskas R, Handelsman DJ. Tetrahydrogestrinone is a potent androgen and progestin. J Clin Endocrinol Metab. 2004 May;89(5):2498-500
2. Catlin D. H., Sekera M. H., Ahrens B. D., Starcevic B., Chang Y. C., Hatton C. K. Tetrahydrogestrinone: discovery, synthesis, and detection in urine. Rapid Commun Mass Spectrom. 2004;18:1245–049.
3. Yu-Chen Chang; Borislav Starcevic; Brian D. Ahrens; M. Jane Strouse; Don H. Catlin. Identification of a Urinary Metabolite of the Designer Steroid Tetrahydrogestrinone (THG). Drug Metab: Toxicology.
4. Fernand Labrie, Van Luu-The, Ezequiel Calvo, Céline Martel, Julie Cloutier, Sylvain Gauthier, Pascal Belleau, Jean Morissette, Marie-Hélène Lévesque, and Claude Labrie J. Endocrinol., Feb 2005; 184: 427 - 433.

01-13-2010, 11:24 PM
Tetrahydrogestrinone is a potent androgen and progestin.

Death AK (http://forums.rxmuscle.com/pubmed?term=%22Death%20AK%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), McGrath KC (http://forums.rxmuscle.com/pubmed?term=%22McGrath%20KC%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Kazlauskas R (http://forums.rxmuscle.com/pubmed?term=%22Kazlauskas%20R%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Handelsman DJ (http://forums.rxmuscle.com/pubmed?term=%22Handelsman%20DJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract).
Heart Research Institute, Camperdown, Sydney, New South Wales 2050, Australia.

Tetrahydrogestrinone (THG) was recently identified as a novel steroid used illicitly to improve athletic performance. Although its structure is closely related to gestrinone, a 19-nor progestin, and resembles that of trenbolone, THG was never marketed, so information on its hormonal properties is not known. In this study, we demonstrate that THG is a highly potent androgen and progestin in a yeast-based in vitro bioassay system expressing human androgen and progesterone receptors. It has no estrogenic activity and no antagonism for any of the three steroid receptor classes.

PMID: 15126583 [PubMed - indexed for MEDLINE]

01-13-2010, 11:28 PM
Tetrahydrogestrinone induces a genomic signature typical of a potent anabolic steroid

Fernand Labrie, Van Luu-The, Ezequiel Calvo, Céline Martel, Julie Cloutier, Sylvain Gauthier, Pascal Belleau, Jean Morissette, Marie-Hélène Lévesque and Claude Labrie

Molecular Endocrinology and Oncology Laboratory, Laval University Medical Research Center (CRCHUL) and Laval University, Québec City, G1V 4G2, Canada

(Requests for offprints should be addressed to F Labrie; Email: [email protected] ([email protected]) )

Tetrahydrogestrinone (THG) is a recently identified compound having the greatest impact in the world of sports. In order to obtain a highly accurate and sensitive assessment of the potential anabolic/androgenic activity of THG, we have used microarrays to identify its effect on the expression of practically all the 30 000 genes in the mouse genome and compared it with the effect of dihydrotestosterone (DHT), the most potent natural androgen. Quite remarkably, we found that 671 of the genes modulated by THG in the mouse muscle levator ani are modulated in a similar fashion by DHT, while in the gastrocnemius muscle and prostate, 95 and 939 genes respectively, are modulated in common by the two steroids. On the other hand, THG is more potent than DHT in binding to the androgen receptor, while, under in vivo conditions, THG possesses 20% of the potency of DHT in stimulating prostate, seminal vesicle and levator ani muscle weight in the mouse. The present microarray data provide an extremely precise and unquestionable signature of the androgenic/anabolic activity of THG, an approach which should apply to the analysis of the activity of any anabolic steroid.