Penile traction therapy does produce measurable results, but the gains are modest and require a serious time commitment. Across clinical studies, men using traction devices gained between 0.5 and 3 cm in stretched length over three to six months, with most results clustering around 1 to 2 cm. For men with Peyronie’s disease, traction reduced penile curvature by an average of 33% in one pilot study. The European Association of Urology includes traction devices in its guidelines for Peyronie’s disease management, though with a moderate level of evidence.
What Traction Actually Does to Tissue
Traction devices work on the same biological principle that orthopedic surgeons use to lengthen bones or that tissue expanders use in reconstructive surgery. Sustained mechanical tension triggers cells to divide and produce new tissue rather than simply stretching existing tissue thinner. In penile tissue specifically, lab research published in The Journal of Sexual Medicine found that tractional forces alter the protein composition of the tunica albuginea, the tough sheath surrounding the erectile chambers. The study showed changes in proteins involved in tissue remodeling, providing what the researchers called “good scientific evidence” for using traction to reshape scar tissue in Peyronie’s disease.
That said, the exact cellular mechanism hasn’t been fully proven. Researchers can observe that the tissue changes, but the precise chain of biological signals that leads from “device applies force” to “tissue grows longer” is still being mapped out.
Results for Penile Lengthening
Several clinical trials have measured length gains in men using traction devices, and the numbers are consistent enough to draw some conclusions. In one study of men who wore a device for at least six hours daily over four months, the average gain in stretched length was 1.8 cm, with a range of 0 to 3.1 cm. Another trial found that after three months of use, flaccid length increased from an average of 8.8 cm to 10.5 cm, while stretched length went from 11.5 cm to 13.2 cm.
Not every study was that encouraging. In men with Peyronie’s disease who used traction for shorter daily periods, the average gain was just 0.3 cm, though this still compared favorably to men who lost an average of 0.7 cm without treatment. A study of men with severe penile retraction from Peyronie’s found an average gain of 0.8 cm with six hours of daily use. Across the full body of evidence, gains generally ranged from 1 to 3 cm and were proportional to total hours of use per month. In one four-month trial with two to four hours of daily wear, 70% of men achieved measurable length gains of up to 1.5 cm.
The honest takeaway: traction can add length, but the realistic expectation for most men is somewhere around 1 to 2 cm over several months of consistent, hours-per-day use.
Results for Peyronie’s Disease
The strongest clinical case for traction therapy is in Peyronie’s disease, where scar tissue causes the penis to curve during erection. In a pilot study of men with Peyronie’s, objective measurements showed curvature reductions of 10 to 45 degrees, with an average group reduction from 51 degrees down to 34 degrees. All men in the study experienced some reduction. Subjectively, participants also reported increased length of 1 to 2.5 cm and improved girth in areas that had been narrowed or indented by the disease.
The European Association of Urology recommends traction devices and vacuum devices to “reduce penile deformity and increase penile length” in Peyronie’s disease, grading the recommendation at level C, meaning it’s based on limited clinical evidence rather than large randomized trials. It’s considered a reasonable conservative option, particularly for men in the early or stable phase of the disease who want to avoid surgery.
After Prostate Surgery
One of the more compelling recent applications is preventing penile shortening after prostatectomy, a common and underreported side effect of prostate removal. A randomized controlled trial found that men who used traction therapy for six months after surgery gained an average of 1.6 cm in stretched length, compared to just 0.3 cm in the control group. The traction group also had significantly better erectile function scores, intercourse satisfaction, and overall sexual satisfaction. Notably, fewer men in the traction group needed injections for erectile dysfunction (19% versus 50%). Adverse events were mild and temporary, with 87% of participants saying they’d repeat the therapy and 93% willing to recommend it.
The Time Commitment Is Significant
This is where most men hit a wall. Clinical protocols have required anywhere from 2 hours to 9 hours of daily device wear, sustained over 3 to 6 months. The most commonly studied older devices, like the Andropenis, recommend 9 hours of daily use for at least three months. Newer devices have tested shorter protocols, with one trial examining sessions of just 30 minutes once, twice, or three times daily. The post-prostatectomy trial that showed strong results used 30 to 90 minutes per day.
Results appear to be dose-dependent, meaning more hours generally produce better outcomes. But the practical reality of wearing a medical device on your penis for six or more hours a day, every day, for months is a major barrier. Clinical trial protocols often note this challenge, and it’s reasonable to assume that real-world compliance is lower than what’s achieved under study conditions.
Traction vs. Vacuum Devices
Vacuum erection devices offer a simpler alternative, particularly for Peyronie’s disease. Animal research comparing the two found that both traction and vacuum devices significantly reduced curvature compared to no treatment. Traction produced a greater reduction in curvature, but vacuum devices better preserved erectile function. From a practical standpoint, vacuum devices are easier to use and more comfortable, though they can be more expensive. For men primarily concerned about curvature, either option shows benefit. For those focused on length, traction has more supporting evidence.
How Long Results Last
This is the biggest gap in the evidence. A systematic review by Germany’s Institute for Quality and Efficiency in Health Care examined the available data and concluded that no study adequately tracked whether curvature or length improvements persist after treatment ends. The key studies measured outcomes at the end of the treatment period, typically three months, without long-term follow-up. One study included a six-month extension phase, but use during that phase was left to patients’ discretion, making it impossible to separate maintained gains from ongoing treatment effects.
In practical terms, this means that while traction therapy produces real, measurable changes during treatment, nobody can say with certainty whether you’ll keep those gains six or twelve months after stopping. It’s plausible that tissue remodeling is permanent, given how traction works in other medical contexts, but the penile-specific data simply hasn’t been collected yet.
Safety Profile
Across studies, traction therapy has a consistently good safety record. Side effects that do occur tend to be mild and temporary: skin irritation, minor discomfort, or transient numbness. No studies have reported serious injuries like tissue damage, nerve injury, or erectile dysfunction caused by the devices. The post-prostatectomy trial specifically noted that all adverse events were “transient and mild.” That said, these results come from supervised clinical settings where patients received proper instruction. Improper use, excessive tension, or wearing a poorly designed device for too long could increase risks that aren’t reflected in the published literature.