Life Cycle of a Penis
Experts explain how a penis changes in size, appearance, and sexual function with age.
What causes the penis to shrink? At least two mechanisms are involved. One is the slow deposit of fatty substances (plaques) inside tiny arteries in the penis, which impairs blood flow to the organ. This process, known as atherosclerosis, is the same one that contributes to blockages inside the coronary arteries -- a leading cause of heart attack.
Goldstein explains that another mechanism involves the gradual buildup of relatively inelastic collagen (scar tissue) within the stretchy fibrous sheath that surrounds the erection chambers. Erections occur when these chambers fill with blood. Blockages within the penile arteries -- and increasingly inelastic chambers -- mean smaller erections.
As penis size changes, so does the size of the testicles. "Starting around age 40, the testicles definitely begin to shrink," Goldstein says. The testicles of a 30-year-old man might measure 3 centimeters in diameter, he says; those of a 60-year-old, perhaps measures only 2 centimeters.
Curvature. If penile scar tissue accumulates unevenly, the penis can become curved. This condition, known as Peyronie's disease, occurs most commonly in middle age. It can cause painful erections and make intercourse difficult. The condition may require surgery.
Sensitivity. Numerous studies have shown that the penis becomes less sensitive over time. This can make it hard to achieve an erection and to have an orgasm. Whether it renders orgasm less pleasurable is still an open question.
Experts say these changes need not ruin your erotic life. One recent study showed significant declines in erectile function, libido, and ejaculatory function in the men studied but only moderate decreases in sexual satisfaction. The study's authors concluded that, "Older men may be less likely to perceive these declines as a problem and be dissatisfied."
As Goldstein puts it, "The most important ingredient for a satisfying sex life is the ability to satisfy your partner. And that doesn't require peak sexual performance or a big penis."