What is the relationship between abnormal Thyroid-Stimulating Hormone (TSH) levels and erectile dysfunction, and how are they treated?

TSH and Erectile Dysfunction: Relationship and Treatment

Direct Answer

Screen for thyroid dysfunction in all men presenting with erectile dysfunction, but postpone specific ED treatment for at least 6 months after achieving euthyroidism, as correcting thyroid abnormalities alone often restores erectile function. 1

The Relationship Between TSH and Erectile Dysfunction

Hyperthyroidism and ED

• Overt hyperthyroidism (suppressed TSH with elevated free T4) dramatically increases the risk of severe erectile dysfunction, with a 14-16 fold increased hazard ratio compared to euthyroid men. 2
• Suppressed TSH levels are independently associated with erectile dysfunction in both community-dwelling men and those seeking treatment for sexual dysfunction. 2
• Approximately 70% of hyperthyroid men experience erectile dysfunction, compared to 34% of controls. 1
• A positive correlation exists between SHIM scores (erectile function) and serum free T4 levels (r = 0.413, p = 0.005), while a negative correlation exists with TSH (r = -0.669, p < 0.001). 1

Hypothyroidism and ED

• Hypothyroidism is associated with erectile dysfunction, with 84% of hypothyroid men experiencing ED compared to 34% of controls. 1
• The evidence regarding primary hypothyroidism and ED is somewhat conflicting—one large study found no association 2, while clinical series demonstrate clear improvement after treatment 1, 3
• Even when treated with levothyroxine and TSH levels are normalized, hypothyroidism remains associated with increased sexual dysfunction prevalence. 4

Treatment Algorithm

Step 1: Initial Screening and Diagnosis

• Measure TSH in all men presenting with erectile dysfunction, regardless of other symptoms. 1, 3
• If TSH is abnormal (suppressed or elevated), measure free T4 to confirm overt thyroid dysfunction versus subclinical disease. 5, 2
• Multiple TSH measurements over 3-6 months should confirm persistent abnormality before initiating treatment. 5

Step 2: Treat Thyroid Dysfunction First

• For hyperthyroidism: Use antithyroid medications (methimazole) or thyroid ablation therapy (radioactive iodine or surgery) depending on etiology. 5
• For hypothyroidism: Initiate oral levothyroxine monotherapy to normalize thyroid hormone levels. 5, 3
• Wait at least 6 months after achieving euthyroidism before considering specific ED treatment, as thyroid correction alone may restore erectile function. 1

Step 3: Reassess After Thyroid Normalization

• After achieving euthyroidism for 6 months, reassess erectile function using validated tools (SHIM questionnaire). 1
• Treatment of thyroid dysfunction results in significant improvement in SHIM scores in both hyperthyroid (p < 0.0001) and hypothyroid (p < 0.0001) patients. 1
• If ED persists after thyroid normalization, proceed to Step 4. 3

Step 4: Add PDE5 Inhibitor Therapy if Needed

• Initiate PDE5 inhibitor therapy (sildenafil, vardenafil, or tadalafil) only after thyroid function is normalized and ED persists. 5, 6
• The combination of thyroid hormone normalization plus PDE5 inhibitors is more effective than either treatment alone. 3, 7
• All patients with thyroid dysfunction-associated ED improved to mild or no ED after combined treatment with thyroid correction and PDE5 inhibitors (p < 0.001). 3
• Base the choice of specific PDE5 inhibitor on patient preferences, cost, and adverse effects profile. 5, 6

Step 5: Consider Testosterone Evaluation

• Measure testosterone levels in men with persistent ED and decreased libido, as testosterone should be routinely measured in all men with erectile dysfunction. 5, 6
• The American College of Physicians does not recommend routine hormonal testing for all ED patients, but suggests individualizing decisions based on clinical presentation such as decreased libido and premature ejaculation. 5
• Men with total testosterone <230 ng/dL usually benefit from testosterone replacement therapy, while those >350 ng/dL do not usually require supplementation. 5
• For symptomatic men with testosterone 231-346 ng/dL, consider a 4-6 month trial of testosterone replacement therapy after careful discussion of risks and benefits. 5

Critical Clinical Pitfalls to Avoid

• Never start PDE5 inhibitors without first screening for and treating thyroid dysfunction in men with ED. 1 Treating the underlying thyroid disorder may completely resolve ED without additional medication.
• Do not assume that normalized TSH on levothyroxine means sexual function will automatically normalize—sexual dysfunction can persist even with biochemical euthyroidism. 4
• Avoid diagnosing subclinical thyroid dysfunction based on a single TSH measurement; confirm with repeat testing over 3-6 months. 5
• PDE5 inhibitors are absolutely contraindicated in patients taking nitrates due to risk of dangerous hypotension. 5, 6
• Do not initiate testosterone therapy in men actively seeking fertility preservation, as it causes azoospermia—use gonadotropin therapy instead. 5, 6

Mechanism and Supporting Evidence

• Thyroid hormones affect erectile function through multiple pathways: blood circulation, endothelial function, and neurogenic relaxation responses. 7
• Hypothyroidism reduces neuronal and endothelial nitric oxide synthase (nNOS and eNOS) expression in penile tissue, which is restored by levothyroxine treatment. 7
• Combined levothyroxine and testosterone treatment completely recovered reduced smooth muscle mass in hypothyroid rats, while monotherapy only partially improved it. 7
• The beneficial effects occur through restoration of both endothelium-dependent and neurogenic relaxation responses in corpus cavernosum tissue. 7

Lifestyle Modifications

• All men with erectile dysfunction should receive counseling on smoking cessation, regular exercise, weight loss, healthy diet (Mediterranean diet), and moderate alcohol consumption. 5, 6
• These lifestyle modifications reduce cardiovascular risk and improve erectile function independent of thyroid status. 5