Clostebol (; also known as 4-chlorotestosterone) usually as the

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...

clostebol acetate, is a synthetic anabolic–androgenic steroid (AAS). Clostebol is the 4- chloro derivative of the natural hormone

testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristi ...

. The chlorination prevents conversion to

dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues includ ...

(DHT) while also rendering the chemical incapable of conversion to

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

. Although usually used as an ester including clostebol acetate (Macrobin, Steranabol, Alfa-Trofodermin, Megagrisevit), clostebol caproate (Macrobin-Depot), or clostebol propionate (Yonchlon), unmodified/non-esterified clostebol is also reported to be marketed, under the brand name Trofodermin-S in

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. Clostebol is a weak AAS with potential use as a

performance enhancing drug Performance-enhancing substances, also known as performance-enhancing drugs (PEDs), are substances that are used to improve any form of activity performance in humans. A well-known example of cheating in sports involves doping in sport, where bann ...

. It is currently banned by the

World Anti-Doping Agency The World Anti-Doping Agency (WADA; french: Agence mondiale antidopage, AMA) is a foundation initiated by the International Olympic Committee based in Canada to promote, coordinate, and monitor the fight against drugs in sports. The agency's key ...

Chlorodehydromethyltestosterone Chlorodehydromethyltestosterone (CDMT; brand name Oral Turinabol), also known as 4-chloro-17β-hydroxy17α-methylandrosta-1,4-dien-3-one, is an anabolic–androgenic steroid (AAS). It is the 4-chloro-substituted derivative of metandienone (dehyd ...

(Oral Turinabol), combining the chemical structures of clostebol and

metandienone Metandienone, also known as methandienone or methandrostenolone and sold under the brand name Dianabol (D-Bol) among others, is an androgen and anabolic steroid (AAS) medication which is still quite often used because of its affordability and eff ...

, was widely used in the

East German East Germany, officially the German Democratic Republic (GDR; german: Deutsche Demokratische Republik, , DDR, ), was a country that existed from its creation on 7 October 1949 until its dissolution on 3 October 1990. In these years the state ...

state-sponsored doping program.

Medical uses

Clostebol acetate ointment has ophthalmological and dermatological use.

Side effects

Chemistry

Clostebol, also known as 4-chlorotestosterone or as 4-chloroandrost-4-en-17β-ol-3-one, is a synthetic

androstane Androstane is a C19 steroidal hydrocarbon with a gonane core. Androstane can exist as either of two isomers, known as 5α-androstane and 5β-androstane. File:androstane.png, 5α-Androstane File:androstane 5beta.png, 5β-Androstane Pharmacology ...

steroid and a

derivative In mathematics, the derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. ...

of testosterone. It is specifically the 4-

chlorinated In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polyme ...

derivative of testosterone.

Society and culture

Nutritional supplements

A related anabolic steroid, methylclostebol, is a common additive in so-called dietary supplements, generally listed in the convoluted form 4-chloro-17α-methyl-androst-4-en-17β-ol-3-one.

Publicized abuse cases

Use of clostebol has led to the suspension of a number of athletes in various sports including Freddy Galvis of the Philadelphia Phillies in 2012,

Dee Gordon Devaris "Dee" Strange-Gordon (born April 22, 1988) is an American professional baseball second baseman, shortstop, and center fielder who is currently a free agent. He has played Major League Baseball (MLB) for the Los Angeles Dodgers, Miami Mar ...

of the Miami Marlins in 2016, Olympic athlete Viktoria Orsi Toth in 2016, Serie A soccer player

José Luis Palomino José Luis Palomino (born 5 January 1990) is an Argentine professional footballer who plays as a centre-back for club Atalanta. Palomino began his professional career with San Lorenzo, before joining Argentinos Juniors in 2013. After the 2013 ...

of Club

Atalanta Atalanta (; grc-gre, Ἀταλάντη, Atalantē) meaning "equal in weight", is a heroine in Greek mythology. There are two versions of the huntress Atalanta: one from Arcadia (region), Arcadia, whose parents were Iasus and Clymene (mythology ...

, and Fernando Tatís Jr. of the

San Diego Padres The San Diego Padres are an American professional baseball team based in San Diego. The Padres compete in Major League Baseball (MLB) as a member club of the National League (NL) West division. Founded in 1969, the club has won two NL penn ...

in 2022. Tatís Jr, who had missed the entirety of the season due to a broken wrist, accepted the suspension while claiming that it was an inadvertent breach after taking a

ringworm Dermatophytosis, also known as ringworm, is a fungal infection of the skin. Typically it results in a red, itchy, scaly, circular rash. Hair loss may occur in the area affected. Symptoms begin four to fourteen days after exposure. Multiple ar ...

medication that he had failed to check the ingredients list for banned substances. and Orlando Galo from Club Sport Herediano in 2022 In 2016, urinalysis resulted in Therese Johaug testing positive for clostebol.

Regulation

In the U.S., clostebol is listed as a

Schedule III controlled substance The prohibition of drugs through sumptuary legislation or religious law is a common means of attempting to prevent the recreational use of certain intoxicating substances. While some drugs are illegal to possess, many governments regulate t ...

, meaning the U.S. federal government considers it to have a potential for abuse as well as a currently accepted medical use.

References

{{Androgen receptor modulators Androgens and anabolic steroids Androstanes Enones Organochlorides World Anti-Doping Agency prohibited substances