Penile curvature has two broad causes: you’re either born with it, or you develop it later in life. The most common acquired cause is Peyronie’s disease, a condition where fibrous scar tissue forms inside the penis and pulls it into a curve. It affects roughly 3 to 9 percent of adult men, with rates climbing with age. Congenital curvature, on the other hand, is present from birth and involves no scar tissue at all.
Peyronie’s Disease: The Most Common Cause
Peyronie’s disease is a connective tissue disorder affecting the tunica albuginea, the tough, flexible sheath that surrounds the erectile chambers of the penis. In Peyronie’s, excessive fibrous tissue accumulates in this sheath, forming a hardened plaque. Because the plaque doesn’t stretch the way healthy tissue does, the penis bends toward the scarred side during an erection.
The exact chain of events that triggers plaque formation isn’t fully understood, but the leading theory centers on trauma. Repeated micro-injuries during sexual intercourse, or even a single forceful bend, can damage the tunica albuginea. In most men, these small injuries heal normally. In men who develop Peyronie’s, the healing process goes into overdrive, laying down dense collagen that hardens into a plaque rather than flexible scar tissue. The result is a firm lump you can sometimes feel through the skin, along with a progressive curve that may worsen over the first 12 to 18 months before stabilizing.
Prevalence rises steadily with age: about 1.5 percent of men in their 30s, 3 percent in their 40s and 50s, 4 percent in their 60s, and 6.5 percent at age 70 and older. Some screening studies have found rates as high as 8.9 percent when men are physically examined rather than self-reporting. The condition most commonly appears between ages 40 and 70, though younger men are not immune.
How Trauma and Injury Play a Role
A penile fracture is the most dramatic form of trauma that can lead to curvature. Despite the name, there’s no bone involved. The tunica albuginea, which becomes thin and rigid during an erection, can rupture from sudden blunt force or an abrupt sideways bend. The most common scenario is the penis slipping out during intercourse and striking the partner’s pubic bone or perineum. A meta-analysis of penile fracture cases found that 46 percent occurred during intercourse, 21 percent from forced bending, 18 percent during masturbation, and about 8 percent from rolling over in bed.
Even without a full fracture, the complications are telling. Penile fractures can lead to abnormal curvature, painful erections, fibrous plaque formation, and erectile dysfunction. These are essentially the same hallmarks of Peyronie’s disease, which supports the idea that less dramatic, repetitive micro-trauma during normal sexual activity can set the same scarring process in motion over time.
Congenital Penile Curvature
Some men have had a curved penis for as long as they can remember. Congenital penile curvature is a developmental condition present from birth, and it becomes noticeable once erections begin during puberty. Unlike Peyronie’s disease, there is no scar tissue or plaque involved. The curve results from the way elastic tissue in the penis formed during fetal development.
Researchers don’t know exactly why this uneven tissue development happens. The curve is typically downward (ventral) and stays stable over time rather than progressing. Because there’s no ongoing scarring process, congenital curvature doesn’t worsen with age. It also doesn’t cause the pain that often accompanies Peyronie’s disease in its early stages. Many men with a mild congenital curve never need treatment. Surgery is generally only considered when the angle is severe enough to interfere with intercourse or cause significant distress.
Conditions Linked to Higher Risk
Peyronie’s disease doesn’t always appear in isolation. Men with Dupuytren’s contracture, a condition where thick tissue forms in the palm and causes fingers to curl inward, have a notably higher rate of Peyronie’s. Both conditions involve abnormal collagen buildup in connective tissue, suggesting a shared genetic or biological tendency toward excessive scarring. Plantar fibromatosis, which causes similar nodules on the sole of the foot, is another related condition.
Diabetes and cardiovascular disease also appear more frequently in men with Peyronie’s. Vascular problems, either in the arteries supplying the penis or in the mechanism that traps blood during an erection, have been found in as many as 70 percent of men who have both erectile dysfunction and Peyronie’s disease. It’s not always clear whether vascular disease contributes to plaque formation or simply coexists, but the overlap is significant enough that a Peyronie’s diagnosis sometimes prompts screening for cardiovascular risk factors.
Erectile Dysfunction and Other Complications
Curvature itself can make intercourse difficult or impossible depending on severity, but the complications go beyond the bend. About 20 percent of men with symptomatic Peyronie’s disease report inadequate erections. In some cases, the plaque disrupts the blood-trapping mechanism that maintains an erection. In others, the psychological burden of a visible deformity contributes to performance anxiety and avoidance of intimacy.
Penile shortening is another common concern. As the plaque contracts, it can pull the affected side inward, reducing overall length. Some men also develop an hourglass or hinge deformity, where the penis narrows or buckles at the plaque site rather than curving smoothly. These changes can be more functionally disruptive than the curve itself.
How Curvature Is Treated
Treatment depends on the cause, the severity of the curve, and whether the condition is still progressing or has stabilized. For Peyronie’s disease, the first step is typically observation during the acute phase, which lasts roughly 6 to 18 months while the plaque is still forming and the curve may be changing. Pain, which is common early on, usually resolves on its own as the disease stabilizes.
Once the curve has been stable for at least three months, active treatment options include injection therapy and surgery. Collagenase injections, delivered directly into the plaque, work by breaking down the excess collagen. In phase 3 clinical trials, men who received a series of injections combined with gentle penile stretching exercises saw an average 34 percent improvement in curvature, translating to roughly a 17-degree reduction. Men who received a placebo improved by about 18 percent. The treatment requires multiple office visits over several months, with stretching exercises performed at home between sessions.
Surgery is reserved for men with stable, severe curves that significantly impair sexual function. Surgical approaches vary depending on the degree of curvature, erectile function, and penile length, but the goal is to straighten the penis enough to allow comfortable intercourse. For men who also have significant erectile dysfunction that doesn’t respond to medication, a penile implant can address both problems simultaneously.
Congenital curvature, when it does require treatment, is corrected surgically. Because there’s no plaque to dissolve, injection therapy has no role. The surgery involves placing stitches on the longer side of the penis to even out the asymmetry, and results are generally straightforward with high satisfaction rates.