Does my weight impact the effectiveness of my hormone replacement therapy with Estrodot (estradiol) and Mirena (levonorgestrel) IUD, and should I consider testosterone testing due to hair loss?

Impact of Weight on Hormone Replacement Therapy Effectiveness and Testosterone Testing for Hair Loss

Yes, your weight may impact the effectiveness of your hormone therapy, and testosterone testing is warranted given your persistent hair loss despite improved ferritin levels.

Weight Impact on Hormone Therapy Effectiveness

Weight can influence the effectiveness of hormone replacement therapy (HRT), particularly when using transdermal estrogen delivery systems like Estrodot:

• Higher body weight (BMI >30 kg/m²) may reduce the bioavailability of transdermal estrogen due to:
  • Altered absorption through skin
  • Increased distribution volume
  • Potential changes in metabolism of hormones

Your BMI of 31 (95kg at 175cm) places you in the obese class I category, which could potentially affect how well your current hormone therapy works.

Specific Considerations for Your HRT Regimen

1. Estradiol Delivery (Estrodot):

   • Transdermal estrogen patches may have variable absorption in patients with higher BMI
   • The fixed dose (50 μg) may not provide optimal estradiol levels for your body weight

2. Progesterone Component (Mirena IUD):

   • The levonorgestrel IUD provides localized progesterone effects primarily to the endometrium
   • Less affected by body weight than systemic hormone delivery 1
   • Continues to provide adequate endometrial protection regardless of weight

Testosterone Testing and Hair Loss

Your continued hair loss despite normalized ferritin levels (93 from 20s) strongly suggests the need for testosterone evaluation:

• Recommendation for testing:

  • Morning serum total testosterone
  • Free testosterone by equilibrium dialysis
  • Sex hormone-binding globulin (SHBG) 1

• Rationale:

  • Post-menopausal women often experience androgenic alopecia due to altered testosterone:estrogen ratios
  • Your history of gastric bypass may affect hormone metabolism and SHBG levels
  • Weight can influence sex hormone binding globulin (SHBG) levels, which affects free testosterone availability 2
  • The Mirena IUD releases levonorgestrel, which can bind to SHBG and potentially displace testosterone, increasing free testosterone levels 2

Recommendations Based on Your Specific Situation

1. For HRT optimization:

   • Consider increasing Estrodot dosage to 75-100 μg or using two 50 μg patches concurrently
   • Maintain the Mirena IUD as it provides adequate endometrial protection regardless of weight
   • Request estradiol level testing to confirm adequate absorption

2. For hair loss evaluation:

   • Complete testosterone panel (total testosterone, free testosterone, SHBG)
   • Consider DHT (dihydrotestosterone) testing
   • Evaluate thyroid function if not recently checked

3. Additional considerations:

   • Your gastric bypass history may affect nutrient absorption related to hair health
   • Continue monitoring iron status despite improved ferritin
   • Consider consultation with an endocrinologist who specializes in post-bariatric surgery hormone management

Potential Pitfalls to Avoid

• Don't assume normalized ferritin alone resolves hair loss - Multiple hormonal factors are likely involved
• Don't overlook the impact of weight on hormone therapy - Dosing may need adjustment based on body weight
• Don't dismiss testosterone evaluation in post-menopausal women - It's crucial for understanding hair loss
• Don't change multiple treatments simultaneously - This makes it difficult to determine which intervention is effective

Regular monitoring of both symptoms and hormone levels will help optimize your treatment regimen and address your ongoing hair loss concerns.