Though sexual desire may wane for most men in the 70s and 80s, a man's teens through his 40s tend to be a time when desire and ability are no issue. A man's sexual peak -- when sexual maturity, ability and desire are at their highest before slowly tapering off -- tends to strike while men are finishing puberty.

Nature and Beyond

Hormonally speaking, men may reach their sexual peak about age 18, when testosterone levels hit their highest levels before gradually declining, according to the Healthline article "Testosterone Levels by Age." In his landmark studies on human sexuality in the 1940s and 1950s, researcher Alfred Kinsey found the ages of 16 to 20 to be peak years of sexual activity for men. As men grow older, desire may taper off and achieving erections may take longer, according to the University of California Santa Barbara article, "Aging and the Sexual Cycle." After hitting a peak in the late teens or early 20s, testosterone levels first begin to dip around the time a man is in his mid-20s. Sexual desire and ability can also be affected by confidence, ability and relationship status, according to "Shape" magazine writer Sophia Breene. Though desire and ability may peak earlier in life, about three-quarters of men still report adequate sexual desire through age 65, writes certified sex therapist Dan Pollets, in the "Psychology Today" article "Aging and Male Sexual Desire II: Physical Factors."