Oxandrolone or Turinabol: What's the Difference

Oxandrolone and turinabol (chlorodehydromethyltestosterone) belong to the oral anabolic steroids and in the popular imagination often stand side by side as «mild» drugs. However, they have different chemical «parents», a different medical history and a different fate in anti-doping control. The editorial team explains what the real differences between these substances are.

Two molecules — two lineages

Oxandrolone is a derivative of dihydrotestosterone (DHT). Its key feature is the replacement of the carbon atom at the second position of ring A with an oxygen atom, hence the name «oxa-». In addition, the molecule has a methyl group at position 17α, which protects it from rapid breakdown in the liver and allows the drug to be taken orally.

Turinabol, or 4-chlorodehydromethyltestosterone, is derived from testosterone via methandienone. In essence, it is the methandienone molecule with an additional chlorine atom at the fourth position. This chlorine atom fundamentally changes the properties: it blocks aromatization and weakens the androgenic activity compared with the «parent» molecule.

Both substances are 17α-alkylated, that is, they belong to the group of oral steroids characterized by a load on the liver. However, the origin from DHT or from testosterone determines a number of other differences — from the possibility of conversion into estrogens to the effect on different tissues.

Such a diagram helps to understand why oxandrolone and turinabol, despite the outward similarity of their use, are pharmacologically different substances with a different set of properties.

History: the clinic versus a state program

Oxandrolone was synthesized in the early 1960s and was used for a long time as a medicine. In the USA it was registered under the name Oxandrin as adjunctive therapy for weight gain after major surgery, injuries, severe infections, during long-term corticosteroid use, and also for relieving bone pain in osteoporosis. According to the instructions, typical doses for adults were 2.5–20 mg per day, divided into several intakes.

Oxandrolone received its most substantial evidence base in burn medicine. Randomized studies in patients with severe burns (Hart et al., 2001; Wolf et al., 2006) showed that it reduces protein catabolism and accelerates the restoration of body weight. The review by Orr and Fiatarone Singh (2004) summarized the data on its use in wasting conditions. However, in 2023 the FDA announced the withdrawal of approval for oxandrolone drugs in the USA.

Turinabol has a fundamentally different history. It was developed by the East German company Jenapharm in the 1960s and became the central substance of the state doping program of the GDR. Documents made public after the reunification of Germany and analyzed by Franke and Berendonk (1997) showed that Oral-Turinabol was systematically given to thousands of athletes, including minors, often without their informed consent.

The health consequences of this program for former athletes — in particular for women, who experienced virilization, impairment of reproductive function and other problems — became the subject of lawsuits and compensation programs. Turinabol, unlike oxandrolone, has no modern medical use.

Pharmacological differences

Both substances act through the androgen receptor but have different auxiliary properties. Oxandrolone, as a DHT derivative, does not aromatize, that is, it is not converted into estrogens. Turinabol, although derived from the aromatizable methandienone, also practically does not undergo aromatization thanks to the chlorine atom at position 4.

Oxandrolone stands out in that in classic animal experiments it demonstrated a high ratio of anabolic to androgenic activity. It was precisely this that once made it attractive for medicine, in particular for use in women and children, although it still has a virilizing potential.

Turinabol is considered a moderate androgen in strength. The chlorine at the fourth position reduces the androgenic action compared with methandienone, and the absence of aromatization rules out estrogenic fluid retention. However, clinical studies in humans comparable to the studies of oxandrolone practically do not exist for it.

Thus, the main difference is not in «strength» but in the volume of scientific knowledge: oxandrolone is known from clinical trials, turinabol — mainly from historical documents and anti-doping research.

Side effects: liver, lipids, hormones

As 17α-alkylated steroids, both substances can cause cholestasis, elevation of liver enzymes, and with prolonged use — hepatic peliosis and tumors. In the instructions for oxandrolone these risks were placed in a boxed warning. The review by Solimini et al. (2017) summarizes cases of hepatotoxicity with illegal steroid use.

A very pronounced common effect is a decrease in HDL cholesterol. For oral 17α-alkylated androgens it is, as a rule, stronger than for injectable testosterone, since the drug in high concentration passes through the liver and changes the activity of hepatic lipase. Oxandrolone, even in medical doses, noticeably reduced HDL in clinical studies.

Suppression of the hormonal axis is another common effect. Although both substances are often considered «mild», any exogenous androgen reduces the secretion of LH and FSH, and hence one's own production of testosterone and spermatogenesis.

• Liver: cholestasis, elevation of ALT/AST, in rare cases — peliosis and tumors.
• Lipids: decrease in HDL, increase in LDL.
• Endocrine system: suppression of LH/FSH, decrease in SHBG.
• Women: risk of virilization, some of the changes are irreversible.

The historical experience of the GDR shows that in women and adolescents even «moderate» oral steroids caused serious, sometimes irreversible changes. This is a reminder that the concept of a «mild steroid» is relative and has no medical meaning.

Metabolism and detection

Both substances are intensively metabolized in the liver. The classic work by Schänzer (1996) describes the general regularities of anabolic steroid metabolism, in particular the formation of 17-epimeric and hydroxylated metabolites used by anti-doping laboratories.

For turinabol, the discovery of long-lived metabolites was a turning point. Sobolevsky and Rodchenkov (2012) described new metabolites that are detected much longer than those previously known. The application of this approach during the reanalysis of samples from the 2008 and 2012 Olympic Games led to numerous positive results and the annulment of awards.

Oxandrolone is eliminated mainly in unchanged form and in the form of several metabolites, for which detection methods have also been developed. Both substances are included in class S1 of the WADA Prohibited List and are prohibited at all times.

For athletes, this story has a simple meaning: modern methods of analysis are constantly improving, and samples are stored for years for retesting. A positive result may appear many years after a competition.

Editorial conclusions

Oxandrolone is a DHT derivative with a history of clinical use and randomized studies, turinabol is a chlorinated modification of methandienone known primarily as an instrument of the GDR's state doping.

Neither substance aromatizes, both are 17α-alkylated, load the liver, reduce HDL and suppress the hormonal axis. The difference lies in the origin of the molecule, the volume of scientific data and the legal status.

The notion of «mild» oral steroids is confirmed neither by clinical data nor by historical experience.

We also recommend reading our materials «Oxandrolone vs Turinabol: what to choose and for whom», on the lipid panel when taking hormonal drugs and on liver tests for athletes.

References

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