Turinabol

Chlorodehydromethyltestosterone (also called 4-chlorodehydromethyltestosterone or dehydrochloromethyltestosterone, sold under the brand name Turinabol) is a synthetic anabolic-androgenic steroid belonging to the 17-alpha-alkylated testosterone derivative class. Its structure combines a 4-chloro substitution on the steroid A-ring with a 1,2-double bond and a 17-alpha-methyl group, giving it a distinct anabolic-to-androgenic profile compared to testosterone.

The 17-alpha-methyl group is the key feature that makes it orally active: it slows hepatic first-pass metabolism so that meaningful amounts reach systemic circulation after ingestion. This modification is shared with many other oral anabolic steroids and is also associated with liver stress. The compound has been banned in sports and is subject to anti-doping screening worldwide.

Human study: Human excretion studies showed that 4-chlorodehydromethyltestosterone undergoes 17-epimerization in vivo, producing epimeric metabolites detectable in urine. The extent of epimerization was found to vary depending on the A-ring structure of the steroid. Note: Excretion/metabolism study in humans involving multiple anabolic steroids including 4-chlorodehydromethyltestosterone. (PMID 1448813)

Laboratory study: A liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for screening 4-chlorodehydromethyltestosterone alongside six other 17-alkyl-substituted anabolic steroids in human urine. The method achieved detection limits of 0.1–2.0 ng/ml with good linearity and high selectivity, demonstrating its suitability for routine anti-doping screening. Note: Doping/detection study; analytical method development using human urine samples. (PMID 15013688)

Laboratory study: The 17-beta-methyl epimer of 4-chlorodehydromethyltestosterone could be distinguished from the 17-alpha-methyl parent compound by gas chromatography retention time and by differences in 1H and 13C NMR chemical shifts. Mass spectrometry differentiation between epimers was possible for this compound, unlike for most others in the series. Note: Analytical/synthetic chemistry study; 17-epimers synthesized and characterized by GC, MS, and NMR. (PMID 1448813)

Laboratory study: Surface-enhanced Raman spectroscopy (SERS) using silver nanoflower substrates with a potassium iodide coagulant successfully detected characteristic spectral peaks of 4-chlorodehydromethyltestosterone alongside three other anabolic steroids. The platform enabled on-site, portable detection in food, aquatic, and pharmaceutical matrices within 70 seconds with satisfactory recovery rates. Note: Doping/detection study; analytical method using silver nanoflower SERS substrates applied to food, aquatic, and pharmaceutical matrices. (PMID 40675078)

Open questions: The available published literature on chlorodehydromethyltestosterone is heavily skewed toward doping detection and analytical chemistry rather than controlled clinical research. Key unanswered questions include: What are the full pharmacokinetic parameters (half-life, volume of distribution, protein binding) in humans under controlled conditions? What are the long-term cardiovascular, hepatic, and endocrine effects at various exposure levels in human cohorts? How does 17-epimerization of this compound affect its biological activity compared to the parent steroid? Are there sex-specific differences in metabolism or toxicity? The absence of modern clinical trial data means most assumptions about efficacy and safety are extrapolated from related compounds or historical, poorly controlled studies.