Can hypogonadism (low testosterone) cause alopecia (hair loss) in men?

Low Testosterone and Hair Loss in Men

Yes, low testosterone (hypogonadism) can contribute to hair loss in men, though the relationship is complex and involves multiple hormonal pathways. 1

Relationship Between Testosterone and Hair Loss

Testosterone Deficiency and Hair Changes

• Low testosterone levels can lead to decreased body hair, including reduction in facial, pubic, chest, and axillary hair 1
• Signs of hypogonadism include decreases in body hair, along with other symptoms like decreased energy, libido, muscle mass, as well as hot flashes and gynecomastia 1

Hormonal Mechanisms

• Testosterone affects hair growth through two main pathways:

  1. Direct testosterone effects
  2. Conversion to dihydrotestosterone (DHT) via 5α-reductase enzyme 2, 3

• While androgenetic alopecia (male pattern baldness) is primarily associated with DHT sensitivity, low testosterone can disrupt the overall hormonal balance affecting hair health 3

Clinical Assessment of Hypogonadism

When to Suspect Low Testosterone

• Consider testosterone assessment in men with:
  • Decreased body and facial hair
  • Reduced energy and libido
  • Decreased muscle mass
  • Erectile dysfunction
  • Hot flashes
  • Gynecomastia 1

Diagnostic Approach

• Morning total testosterone level (drawn between 8-10 AM) is the initial test 1
• Normal testosterone range for adult men: 300-800 ng/dL 1
• If total testosterone is borderline low, check:
  • Free testosterone level by equilibrium dialysis
  • Sex hormone-binding globulin (SHBG) 1
• Further testing (LH, FSH) helps distinguish primary from secondary hypogonadism 1
• Repeat testing is recommended to confirm low levels 1

Treatment Considerations

Testosterone Replacement

• In men with confirmed symptomatic hypogonadism, testosterone replacement may:
  • Improve sexual function and libido
  • Increase well-being
  • Enhance muscle mass and strength
  • Improve bone density 1
  • May help with body hair growth, though effects on scalp hair are complex 1

Treatment Options

• Transdermal preparations (gels, patches) are commonly used due to:
  • More stable day-to-day testosterone levels
  • Avoidance of injection discomfort 1
• Injectable testosterone offers:
  • Less frequent administration
  • May be better for patients with limited self-management skills 1
• Implantable pellets provide longer-term treatment but require a procedure 1

Important Caveats

Potential Risks

• Testosterone replacement in older men with hypogonadism has been associated with:
  • Increased coronary artery plaque volume
  • Potential increase in cardiovascular events in some studies 1

Diagnostic Pitfalls

• Obesity is a major confounder in testosterone assessment 1
• In obese men, low total testosterone may be due to reduced SHBG rather than true hypogonadism 1
• Morning testing is essential as testosterone levels fluctuate throughout the day 1

Paradoxical Effects on Hair

• While low testosterone can reduce body hair, the relationship with scalp hair is more complex
• DHT (converted from testosterone) is implicated in male pattern baldness, creating a paradoxical situation where both high and low androgen states can affect different hair follicles differently 2, 3

Conclusion

When evaluating hair loss in men with suspected hypogonadism, a thorough hormonal assessment is necessary to determine if low testosterone is contributing to the condition. Treatment decisions should be based on confirmed laboratory values and the presence of symptomatic hypogonadism, weighing the potential benefits against cardiovascular risks.