Does Transdermal Testosterone Treatment Cause BPH?
No, transdermal testosterone treatment does not cause benign prostatic hyperplasia (BPH), though it may modestly increase prostate volume to normal levels without worsening urinary symptoms. 1, 2
Evidence Against Causation
Multiple high-quality studies demonstrate that testosterone replacement therapy does not exacerbate BPH:
Multiple studies have failed to demonstrate worsening of voiding symptoms attributable to BPH during testosterone supplementation, and complications such as urinary retention have not occurred at higher rates than in placebo-controlled trials. 1, 2
The European Association of Urology confirms that TRT is safe and does not worsen lower urinary tract symptoms (LUTS) or prostate volume significantly, except in men with severe pre-existing symptoms. 2
A 2022 randomized clinical trial specifically found that 24 weeks of testosterone therapy in men with BPH and metabolic syndrome showed no differences in improvement of urinary symptoms between testosterone and placebo groups. 3
The Prostate Volume Paradox
While testosterone does affect prostate size, this does not translate to clinical problems:
Prostate volume increases significantly during testosterone replacement therapy, mainly during the first six months, reaching levels equivalent to men without hypogonadism. 1
However, urine flow rates, post-voiding residual urine volumes, and prostate voiding symptoms did not change significantly in these studies. 1
This apparent paradox is explained by the poor correlation between prostate volume and urinary symptoms—larger prostates do not necessarily cause worse symptoms. 1
In the 2022 trial, testosterone increased total prostate volume by 2.64 mL but did not increase adenoma volume (1.82 mL change was not significant), and actually improved ultrasound markers of inflammation. 3
Clinical Safety Profile
The American College of Physicians' 2020 systematic review provides reassuring long-term data:
Evidence from 20 observational studies with mean follow-up ranging from 0.73 to 10.3 years showed no increased risk for mortality, cardiovascular events, prostate cancer, or thromboembolic events. 1
No consistent differences in harms were observed between transdermal versus intramuscular formulations. 1
The most common adverse reaction in controlled trials was increased PSA (11.1% of patients), though most cases resolved or remained clinically insignificant. 4
When to Proceed with Caution
The European Association of Urology provides specific guidance on safe TRT use in BPH patients:
Proceed with TRT if the patient has mild to moderate BPH symptoms, normal or stable PSA, and no evidence of prostate cancer. 2
Severe BPH symptoms remain a relative contraindication where more caution is warranted. 2
Individual men with hypogonadism may occasionally experience increased voiding symptoms with testosterone therapy, though this is uncommon. 1
Required Monitoring Protocol
When initiating transdermal testosterone in men with or at risk for BPH:
Assess urinary symptoms at 3-6 months initially, then annually. 2
Monitor PSA levels every 3-6 months for the first year, then annually. 2
Perform digital rectal examination at each monitoring visit. 2
Consider prostate biopsy if PSA rises >1.0 ng/mL in any year or if digital rectal examination shows changes. 2
Biological Mechanism
The relationship between testosterone and BPH is permissive rather than causative:
BPH development requires the presence of androgens and aging, but androgens play a permissive role rather than being the causative factor. 1, 5
The principal prostatic androgen is dihydrotestosterone (DHT), which remains at normal levels in the prostate with aging despite decreased plasma testosterone. 5
Testosterone therapy restores physiologic levels but does not create supraphysiologic androgen exposure in prostate tissue. 1