Thyroid Stimulating Hormone

When high

When high (suggestive of hypothyroidism or recovering from T3/T4 cycle):

Supplements:

• Selenium -- 200mcg/day, supports T4-to-T3 conversion
• Ashwagandha -- 300-600mg/day (5% withanolides), may support thyroid function
• L-Tyrosine -- 1000-2000mg/day (thyroid hormone precursor, under supervision)
• Ensure adequate Iodine intake (150-300mcg/day; do not mega-dose)
• Zinc -- 30mg/day (cofactor for thyroid hormone synthesis)

Lifestyle:

• Reduce stress and improve sleep to normalise cortisol (affects thyroid function)
• Ensure adequate caloric intake; prolonged deficits suppress T4 production

Pharmacological options (physician-supervised):

• Levothyroxine (Synthroid/T4) -- starting dose typically 25-50mcg/day, titrated by TSH and Free T4 over 6-8 weeks; first-line for confirmed primary hypothyroidism
• Liothyronine (Cytomel/T3) -- 5-25mcg/day, occasionally added to T4 if conversion is poor (low Free T3 despite normalised T4); monitor for tachycardia and arrhythmia

When to escalate:

• TSH >10 mIU/L, or TSH 4-10 with low Free T4 -> overt hypothyroidism, refer to endocrinologist
• Positive anti-TPO/anti-TG antibodies -> Hashimoto's thyroiditis; consider gluten-free trial
• TSH normalises within 4-8 weeks after stopping T3/T4; if not, investigate primary cause

When low

When low (suggestive of hyperthyroidism, exogenous T3/T4 suppression, or central hypothyroidism):

First step -- identify the cause:

• Currently on T3 (Cytomel) or T4 (Synthroid/levothyroxine)? Suppression is expected; check Free T3 and Free T4 to verify they're not over-replaced.
• Off all thyroid hormones with low TSH? Order Free T3, Free T4, TSH receptor antibodies (TRAb), and consider thyroid ultrasound.
• Symptoms of hyperthyroidism: tachycardia, palpitations, anxiety, tremor, heat intolerance, sweating, weight loss, diarrhoea, insomnia.

If on exogenous thyroid hormones (most common cause in PED users):

• Reduce T3/Cytomel dose; suppression is dose-dependent and resolves within 2-4 weeks of stopping
• Taper T3 slowly (reduce by 5-10mcg every 3-5 days) to avoid rebound hypothyroid symptoms
• Recheck TSH 4-6 weeks after taper completes; if still suppressed, investigate further

If hyperthyroidism is confirmed (low TSH + high Free T3/T4 + symptoms):

• Beta-blockers (Propranolol 20-40mg 2-3x/day, or Atenolol 25-50mg/day) -- first-line symptomatic relief for palpitations, tremor, anxiety; physician-prescribed
• Methimazole (Tapazole) -- 5-30mg/day, blocks thyroid hormone synthesis; first-line for Graves' disease in most cases
• Propylthiouracil (PTU) -- 50-150mg 3x/day, blocks T4 to T3 conversion peripherally; second-line due to hepatotoxicity
• Endocrinologist referral for definitive management (radioactive iodine ablation or thyroidectomy if medication fails)

Supplements (supportive only, do NOT replace medical management of hyperthyroidism):

• L-Carnitine -- 2-4g/day; modest evidence for blunting hyperthyroid symptoms (Benvenga 2001) without affecting thyroid hormone levels directly
• Magnesium glycinate -- 300-400mg/day; calms nervous system, supports sleep
• Selenium -- 200mcg/day; reduces TRAb antibodies and may improve outcomes in mild Graves'/Hashimoto's
• Vitamin D3 -- 5000 IU/day if deficient; low vitamin D is associated with autoimmune thyroid disease

Lifestyle:

• Avoid stimulants (caffeine, pre-workouts, ephedrine, clenbuterol) -- they amplify hyperthyroid symptoms
• Avoid iodine excess (kelp supplements, high-iodine foods) until cause is identified
• Manage stress; chronic adrenergic stimulation worsens symptoms

When to escalate (urgent):

• TSH <0.01 with Free T4 >2x upper limit, severe symptoms, fever, confusion -> thyroid storm; emergency department
• Heart rate persistently >120 bpm at rest, atrial fibrillation, or chest pain -> cardiology and endocrinology referral
• Any low TSH off-cycle without obvious cause -> endocrinologist within 4-6 weeks