17beta-hydroxy-1alpha-methylandrost-4-ene-3-one 17β-Hydroxy-1α-methylandrost-4-en-3-one 1α-Methyltestosterone (1S,8R,9S,10R,13S,14S,17S)-17-hydroxy-1,10,13-trimethyl-1,2,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-3-one (1α,17β)-17-Hydroxy-1-methylandrost-4-en-3-one Mesterolone impurity A CRS Androst-4-en-3-one, 17-hydroxy-1-methyl-, (1α,17β)- Mesteralone EP Impurity A