Libido is mistakenly thought by many to come from estrogen.
Progesterone is an important factor in libido.
Testosterone also improves libido and doctors who are unaware of the role of progesterone in libido are sometimes tempted to give women testosterone to help restore flagging libido. However, this choice is less desirable because of the masculinizing effects of testosterone. The more desirable choice is natural progesterone. The body, in any event, has the capability of converting excess progesterone to other hormones including estrogen and testosterone on an as-needed basis. Among many researchers, testosterone is given credit for being the hormone attached to sex drive in both males and females.