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1-Testosterone molecule ball.png
Clinical data
Other names1-Testo; 1-T; δ1-Dihydrotestosterone; δ1-DHT; Dihydroboldenone
Drug classAndrogen; Anabolic steroid
Legal status
Legal status
Pharmacokinetic data
  • (5S,8R,9S,10R,13S,14S,17S)-17-hydroxy-10,13-dimethyl-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-3-one
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.164.058 Edit this at Wikidata
Chemical and physical data
Molar mass288.431 g·mol−1
3D model (JSmol)
  • O=C4\C=C/[C@]1([C@@H](CC[C@@H]2[C@@H]1CC[C@@]3([C@@H](O)CC[C@@H]23)C)C4)C
  • InChI=1S/C19H28O2/c1-18-9-7-13(20)11-12(18)3-4-14-15-5-6-17(21)19(15,2)10-8-16(14)18/h7,9,12,14-17,21H,3-6,8,10-11H2,1-2H3/t12-,14-,15-,16-,17-,18-,19-/m0/s1 checkY
 ☒NcheckY (what is this?)  (verify)

1-Testosterone (abbreviated and nicknamed as 1-Testo, 1-T), also known as δ1-dihydrotestosterone (δ1-DHT), as well as dihydroboldenone, is a synthetic anabolic–androgenic steroid (AAS) and a 5α-reduced derivative of boldenone (Δ1-testosterone). It differs from testosterone by having a 1(2)-double bond instead of a 4(5)-double bond in its A ring.[1] It was legally sold online in the United States until 2005, when it was reclassified as a Schedule III drug.

Side effects[edit]



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 in a manner that is 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 anabolic steroid testosterone propionate, but, unlike testosterone propionate, 1-testosterone also increases liver weight.[2]


1-Testosterone, IUPAC name 17β-hydroxy-5α-androst-1-en-3-one, also known as 4,5α-dihydro-δ1-testosterone (Δ1-DHT) or as 5α-androst-1-en-17β-ol-3-one, is a synthetic androstane steroid and a derivative of dihydrotestosterone (DHT).


Two prohormones of 1-testosterone are 1-androstenediol and 1-androstenedione, the latter of which may be synthesized from stanolone acetate.[3]

Mesabolone is a ketal made from 1-testosterone.

1-Testosterone also is known to be used to synthesize mestanolone and metenolone.[citation needed]

Methyl-1-testosterone is the 17α-methyl derivative of 1-testosterone.

Detection in body fluids[edit]

Doping with 1-testosterone can be detected in urine samples using gas chromatography.[4]


  1. ^ William Llewellyn (2009). Anabolics (9 ed.). Molecular Nutrition. p. 22,135. ISBN 978-0-9679304-7-3.
  2. ^ 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. doi:10.1016/j.toxlet.2006.03.001. PMID 16621347.
  3. ^ Zhang H, Qiu Z (December 2006). "An efficient synthesis of 5α-androst-1-ene-3,17-dione". Steroids. 71 (13–14): 1088–90. doi:10.1016/j.steroids.2006.09.008. PMID 17123559. S2CID 53258890.
  4. ^ S. Jain, A. Beotra and T. Kaur (2005). "A Case Study: Detection of 1-Testosterone in Urine by GC-MSD" (PDF). Recent Advances in Doping Analysis. 13: 407–410. Archived from the original (PDF) on 2011-08-25. Retrieved 2011-06-18.