Androst-4-en-19-ones for the enhancement of libido

A method of enhancing the libido of mammals in need thereof which comprises the administration to such mammal of a therapeutically effective amount of an androst-4-en-19-one having the formula ##STR2## wherein R.sub.1 and R.sub.8 are each selected from the group consisting of hydrogen, acyl having from 1 to 12 carbon atoms, lower alkyl having from 1 to 3 carbon atoms, trialkylsilyl in which the alkyl group has from 1 to 5 carbon atoms, triphenylsilyl, 2-tetrahydropyranyl, 4-tetrahydropyranyl, 1-cycloalkenyl having from 5 to 7 carbon atoms, 1-methoxycycloalkyl and 1-ethoxycycloalkyl in which the cycloalkyl group has from 5 to 7 carbon atoms,

• R.sub.2 is selected from the group consisting of hydrogen, lower alkyl having from 1 to 6 carbon atoms, lower alkenyl having from 2 to 6 carbon atoms, lower alkynyl having from 2 to 6 carbon atoms, and when R.sub.2 and OR.sub.1 are taken together is oxo,
• R.sub.3, r.sub.4, r.sub.5 and R.sub.7 are hydrogen and methyl, and
• R.sub.6 is selected from the group consisting of H.sub.2, oxo and H(OR.sub.8).