| US: Schedule III|
1-Testosterone (abbreviated as 1-Testo, 1-T), also known as 4,5α-dihydro-δ1-testosterone (Δ1-DHT) or 5α-androst-1-en-17β-ol-3-one, as well as dihydroboldenone, is an androgenic-anabolic steroid (AAS) that differs from testosterone by having a 1(2)-double bond instead of a 4(5)-double bond in its A ring. It was legally sold online 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 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.
Doping with 1-testosterone can be detected in urine samples using gas chromatography.
Two prohormones of 1-testosterone are 1-androstenediol and 1-androstenedione, the latter of which may be synthesized from stanolone acetate.
Mesabolone is a ketal made from 1-T.
1-T also is known to be used to synthesize mestanolone and metenolone.
Methyl-1-testosterone is 17-methyl 1-T.