Testosterone Therapy Does Not Cause Mouth Sores
Mouth sores are not a recognized side effect of testosterone replacement therapy based on comprehensive guideline evidence and clinical monitoring data. The well-established adverse effects of testosterone therapy include skin reactions at application sites, erythrocytosis, sleep apnea, gynecomastia, testicular atrophy, and prostate-related changes—but oral mucosal lesions are notably absent from these documented complications 1, 2.
Documented Dermatologic Effects of Testosterone
The skin reactions associated with testosterone therapy are specifically localized to application sites and do not involve oral mucosa:
- Transdermal patches cause local skin reactions in up to 66% of users, manifesting as erythema or pruritus at the patch site 1, 2, 3
- Gel preparations cause skin reactions in only 5% of users, again limited to application areas 1, 2, 3
- Intramuscular injections can cause local pain, soreness, bruising, erythema, swelling, nodules, or furuncles at injection sites 1
- Acne is a recognized systemic dermatologic effect but does not manifest as oral ulceration 1
Why Mouth Sores Are Not Associated with Testosterone
The comprehensive monitoring guidelines for testosterone therapy, published in the New England Journal of Medicine and endorsed by the American Urological Association, detail extensive adverse effect profiles without any mention of oral mucosal complications 1, 2. These guidelines specifically enumerate:
- Respiratory effects (sleep apnea) 1, 2
- Cardiovascular effects (erythrocytosis, fluid retention) 1, 2
- Prostate effects (benign prostatic hyperplasia, theoretical cancer risk) 1, 2
- Reproductive effects (testicular atrophy, infertility) 1, 2
- Breast effects (gynecomastia) 1
- Hepatic effects (with oral preparations only, which are strongly discouraged in the United States) 1, 2
The absence of oral mucosal effects from these comprehensive safety profiles is significant, as these guidelines represent decades of clinical experience and systematic monitoring.
Alternative Explanations to Consider
If a patient on testosterone therapy develops mouth sores, investigate other causes:
- Oral testosterone preparations (not testosterone undecanoate) can cause hepatotoxicity, but this manifests as liver dysfunction rather than oral ulceration, and these formulations are strongly discouraged in the United States 1, 2
- Coincidental oral conditions unrelated to testosterone therapy (aphthous ulcers, herpes simplex, nutritional deficiencies, autoimmune conditions)
- Other medications the patient may be taking concurrently
- Systemic conditions that commonly present with oral manifestations
Clinical Monitoring Does Not Include Oral Examination
The standardized monitoring protocols for testosterone therapy focus on hematocrit/hemoglobin, PSA, digital rectal examination, sleep apnea assessment, and voiding symptoms 2. The absence of oral cavity examination from these protocols further confirms that oral mucosal complications are not an expected adverse effect requiring surveillance 2.