Systematic (IUPAC) name
Clinical data
Legal status
Pharmacokinetic data
Metabolism Liver
CAS number
ATC code ?
ChemSpider  YesY
Chemical data
Formula C19H28O2 
Mol. mass 288.42

1-Testosterone (delta1-dihydrotestosterone, 17β-hydroxy-5alpha-androst-1-en-3-one, 1-Testo, 1-T) is an anabolic steroid that differs from testosterone by having a 1,2-double bond instead of 4,5-double bond in its A ring. It was legally sold as a prohormone in the United States until 2005, when it was reclassified as a Schedule III drug.

A 2006 study determined that 1-testosterone has a high androgenic and anabolic potency even without being metabolized, so it can be characterized as a typical anabolic steroid. 1-Testosterone binds highly selective to the androgen receptor (AR) and has a high potency to stimulate AR dependent transactivation. In vivo, an equimolar dose of 1-testosterone has the same potency to stimulate the growth of the prostate, the seminal vesicles and the androgen sensitive levator ani muscle as the reference AAS testosterone propionate, but unlike it, 1-testosterone also increases liver weight.[1]

Doping with 1-testosterone can be detected in urine samples using gas chromatography.[2]

A prodrug of 1-testosterone is 5α-androst-1-ene-3,17-dione, which may be synthesized from stanolone acetate.[3]


  1. ^ Friedel A, Geyer H, Kamber M, Laudenbach-Leschowsky U, Schänzer W, Thevis M, Vollmer G, Zierau O, Diel P (August 2006). "17beta-hydroxy-5alpha-androst-1-en-3-one (1-testosterone) is a potent androgen with anabolic properties". Toxicol. Lett. 165 (2): 149–55.  
  2. ^ S. Jain, A. Beotra and T. Kaur (2005). "A Case Study: Detection of 1-Testosterone in Urine by GC-MSD". Recent Advances in Doping Analysis 13: 407–410. 
  3. ^ Zhang H, Qiu Z (December 2006). "An efficient synthesis of 5α-androst-1-ene-3,17-dione". Steroids 71 (13-14): 1088–90.