What randomized trials exist comparing penile traction therapy to sham therapy for penile length gains?
Executive summary
A targeted review of the available randomized trials shows no study in the provided reporting that used a true sham device to mask traction versus active penile traction therapy (PTT); instead, randomized evidence compares PTT (usually the RestoreX device) to no‑treatment control arms and reports modest mean length gains of roughly 1.5–2.0 cm over months of use [1] [2] [3]. The strongest randomized data are two RestoreX trials — one in men with Peyronie’s disease (n=110, randomized 3:1 to PTT vs control) and one post‑prostatectomy trial (n≈82 randomized across control and two PTT dosing arms) — but both used no‑treatment controls rather than sham devices and have limitations including short randomized follow‑up and industry‑linked device development [1] [4] [5].
1. The Peyronie’s randomized trial everybody cites — active device versus no therapy
The largest randomized, single‑blind trial reported randomized 110 men with Peyronie’s disease 3:1 to the RestoreX traction device (30–90 minutes daily) or to no therapy for three months and found statistically significant length increases in the PTT group (mean ~1.5–1.6 cm) and high responder rates (94% with some length increase and 10.9% with ≈1.6 cm gains reported as a subgroup), along with curvature and erectile‑function improvements; this trial was registered as NCT03389854 and published in Journal of Urology and follow‑up phases in the Journal of Sexual Medicine [1] [4] [3] [6]. The trial design was single‑blind with objective curvature assessments and standardized questionnaires but the control arm received no traction device, not a sham, which leaves open the possibility that expectation and adherence effects influenced subjective outcomes [3] [4].
2. Post‑prostatectomy randomized data — protocol comparisons, not sham controls
A single‑center randomized, controlled trial of RestoreX in men after radical prostatectomy randomized roughly 82 patients into control or one of two PTT dosing regimens for six months and reported preservation or improvement of penile length and some gains in erectile function in the device arms during the randomized phase; the publication and abstracts describe randomization to no‑treatment control versus active PTT arms, again without a sham device comparator [7] [5] [8]. The prostatectomy trial included two active dosing strategies and an open‑label extension, providing useful dosing and tolerability data but not addressing the specific methodological question of blinding with a sham traction device [7] [8].
3. Systematic reviews and the state of the evidence — RCTs exist but sham trials do not
Contemporary narrative and systematic reviews of PTT cite the recent randomized RestoreX trials and conclude that modern RCT evidence supports PTT’s safety and short‑term efficacy for length and curvature, but they uniformly note the limited number of randomized controlled trials, small samples, variable protocols and the absence of long‑term sham‑controlled data; reviews call for additional randomized trials with longer follow‑up and more rigorous control arms to address placebo and expectation effects [9] [10] [11]. Meta‑analytic summaries pool RCT and cohort data but also emphasize heterogeneity and the need for further randomized comparisons [10].
4. What’s missing and why it matters — no sham PTT trials in current reporting
None of the provided sources describe a randomized trial that used a physiological sham traction device designed to mimic wearing a device without applying therapeutic tensile force; instead, the randomized comparisons are against “no therapy” controls, which simplifies trial logistics but limits ability to separate mechanical efficacy from placebo, measurement bias, and adherence‑related benefits — an important methodological gap for any device‑based therapy [1] [4] [3] [9]. The RestoreX studies’ industry collaboration and device innovation are disclosed in the reports (device developed in cooperation with Mayo Clinic and PathRight/RestoreX commercial ties), which is relevant when interpreting enthusiastic efficacy claims from single‑manufacturer devices [1] [3].
5. Bottom line for researchers and clinicians
Randomized evidence supports short‑term penile length gains with RestoreX PTT compared with no‑treatment controls in Peyronie’s disease and in the post‑prostatectomy setting, with mean gains on the order of 1.5–2.0 cm reported in intent‑to‑treat analyses across trials; however, the literature identified here contains no randomized, sham‑controlled trials that would more definitively isolate the device’s mechanical effect from placebo and measurement bias, and reviewers call for larger, longer, and better‑blinded trials to settle those questions [1] [2] [10].