Does Armour Thyroid cause hair loss?

Hair loss and thinning hair can be symptoms of hypothyroidism (low thyroid hormone levels). Treating this with thyroid hormone replacement—whether Armour Thyroid (desiccated thyroid), NP Thyroid, or Synthroid (levothyroxine)—often improves thyroid‑related hair loss. However, you may notice worsened shedding after starting treatment. This usually reflects the time needed for thyroid hormone levels to stabilize and for hair follicles to adjust to the new hormone environment. In most cases, this transient shedding lasts 4 to 8 weeks.

How does your thyroid affect your hair?

The thyroid gland in your neck produces hormones that regulate many cellular functions, including those in hair follicles. When thyroid output is too high (hyperthyroidism), cells speed up and symptoms can include anxiety, tremors, weight loss and hair thinning. When output is too low (hypothyroidism), cellular processes slow and you may experience fatigue, weight gain, constipation and hair thinning. Hair growth follows a cycle:

  • Growth phase (anagen)
  • Transition phase (catagen)
  • Resting phase (telogen)
  • Shedding phase (exogen)

In hypothyroidism, more follicles enter telogen prematurely, leading to increased shedding and thinning.

Preventing hair loss during Armour Thyroid therapy

  • Have your provider monitor TSH, free T4 and free T3 every few weeks to fine‑tune your dose.
  • Eat a balanced diet rich in protein, iron, zinc, selenium, biotin (B vitamins), vitamin C and vitamin D.
  • Consider supplements if dietary intake is insufficient.
  • Manage stress through exercise, mindfulness or therapy.
  • Avoid harsh hair treatments, heat styling and tight hairstyles.

Other side effects of Armour Thyroid

  • Increased heart rate or palpitations
  • Chest pain
  • Tremors
  • Muscle weakness
  • Excessive sweating
  • Anxiety or nervousness
  • Diarrhea
  • Rare but serious: severe allergic reactions, cardiac complications, adrenal insufficiency symptoms, elevated blood sugar

Why some doctors avoid Armour Thyroid

  • It lacks formal FDA approval and batch consistency can vary.
  • Risk of over‑ or under‑dosing, especially in sensitive patients.
  • Boxed warning: not for weight loss in euthyroid individuals.
  • Alternative synthetic options (levothyroxine, liothyronine) offer consistent potency.

Sources

  • Armour Thyroid Package Insert. AbbVie, Inc., 2024.
  • National Institute of Diabetes and Digestive and Kidney Diseases: Hypothyroidism Overview.
  • Hussein RS et al. Impact of Thyroid Dysfunction on Hair Disorders. Cureus. 2023;15(8):e43266.
  • Almohanna HM et al. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019;9(1):51–70.