What supplements are recommended for patients with hypothyroidism?

Supplements for Hypothyroidism

For patients with hypothyroidism, levothyroxine is the standard treatment, and routine supplementation with iodine (150 μg daily) is recommended only in cases of documented iodine deficiency. 1

Thyroid Hormone Replacement

Levothyroxine (Standard Treatment)

• Initial dosing:
  • For most adults without risk factors: 1.6 μg/kg/day 2
  • For elderly patients (>70 years) or those with cardiac disease: Start lower at 25-50 μg/day and titrate gradually 1
  • Goal: Normalize TSH levels (typically 0.4-4.0 mIU/L) 3

Monitoring and Dose Adjustment

• Check TSH and free T4 every 6-8 weeks while titrating dose 1
• Once stabilized, monitor every 6-12 months 1
• Adjust dose based on clinical response and laboratory values

Nutritional Supplements

Iodine

• Only recommended in documented iodine deficiency 1
• Standard supplementation: 150 μg/day 1
• Upper limit: 300 μg/day 1
• Caution: Excessive iodine intake can worsen autoimmune thyroiditis and cause hypothyroidism 1

Vitamin D

• Supplement with native vitamin D (cholecalciferol or ergocalciferol) if deficient 1
• No evidence for routine supplementation in hypothyroidism without deficiency

Special Considerations

Pregnancy

• Women who become pregnant should increase their weekly levothyroxine dosage by 30% (take one extra dose twice weekly) 2
• Monthly monitoring and adjustment during pregnancy

Persistent Symptoms Despite Normal TSH

• Reassess for other causes of symptoms
• Consider endocrinology referral
• Note: Combination therapy with T3 (liothyronine) is not routinely recommended despite persistent symptoms 2, 4

Common Pitfalls to Avoid

1. Over-supplementation with iodine: Can worsen autoimmune thyroiditis and trigger thyroid dysfunction 1
2. Inadequate monitoring: Failure to check TSH and free T4 at appropriate intervals
3. Inappropriate levothyroxine dosing: Starting at full dose in elderly or cardiac patients
4. Ignoring drug interactions: Certain medications can affect levothyroxine absorption (take on empty stomach)
5. Missing central hypothyroidism: Low TSH with low free T4 requires different management approach 1

Algorithm for Managing Hypothyroidism

1. Confirm diagnosis with TSH and free T4
2. Determine appropriate starting dose based on age and comorbidities
3. Start levothyroxine therapy
4. Monitor TSH and free T4 every 6-8 weeks during initial titration
5. Adjust dose to normalize TSH (0.4-4.0 mIU/L)
6. Once stable, monitor annually
7. Consider iodine supplementation only if deficiency is documented

While some patients report benefits from alternative supplements or combination therapy with T3, the evidence does not support their routine use, and levothyroxine monotherapy remains the standard of care for optimizing morbidity, mortality, and quality of life outcomes in hypothyroidism.