Thyroid Foundation (Hypo)

Creator: Pilora
Published: 2026-05-20

thyroidmoderate evidence

About this protocol

Hypothyroidism — outside of autoimmune Hashimoto''s — is most commonly due to iodine deficiency in some populations, selenium deficiency, or post-medical causes (radiation, surgery, medication-induced). In iodine-replete countries, autoimmune Hashimoto''s accounts for the majority of cases (see the Hashimoto''s protocol). This protocol is for non-autoimmune hypothyroidism or subclinical hypothyroidism without elevated TPO antibodies — selenium, low-dose iodine (only if deficiency is documented), tyrosine (precursor to thyroid hormones), and B12 for the fatigue often accompanying hypothyroidism. If you have confirmed Hashimoto''s (positive TPO antibodies), use that protocol instead — iodine supplementation is potentially harmful in autoimmune thyroid disease. Treatment of confirmed hypothyroidism is levothyroxine. Supplements do not replace thyroid hormone replacement. They support endogenous function and address common cofactor deficiencies.

Where to start

Get the right labs first: TSH, free T4, free T3, TPO antibodies, thyroglobulin antibodies, and a urinary iodine spot or 24-hour test if iodine status is uncertain. Distinguish autoimmune (positive antibodies — use Hashimoto''s protocol) from non-autoimmune hypothyroidism.

Start with selenium. Supports T4-to-T3 conversion and overall thyroid function. Cap at 200 mcg/day.

Iodine — only if documented deficient. Urinary iodine under 100 mcg/L indicates deficiency. Use low-dose (150-200 mcg/day) for replete diets, or moderate dose (300-500 mcg/day) for documented deficiency. NEVER supplement iodine in Hashimoto''s.

L-tyrosine is the amino acid precursor to T4. Useful when low-normal thyroid hormones cause fatigue and cognitive dullness. Activating; morning only.

B12 (methylcobalamin) for the fatigue and cognitive symptoms that accompany hypothyroidism. Coexistent B12 deficiency is common.

If your TSH is over 4.5 mIU/L or you have hypothyroid symptoms, see your doctor about levothyroxine. Supplements support; they do not replace medical management of confirmed hypothyroidism.

4 nutrients

Start here

Strongest evidence — the foundation of the stack.

Selenium (Selenomethionine)

100-200 mcg daily, with breakfast

morningwith food

Selenium is essential for T4-to-T3 conversion via the deiodinase enzymes. Adequate selenium status improves thyroid function in deficient individuals. Most diets meet RDA from foods (Brazil nuts, fish, eggs) but supplementation is reasonable insurance. Cap at 200 mcg/day — higher doses are toxic.^{[1, 2]}

Iodine (low-dose, only if deficient)

150-300 mcg daily — TEST FIRST, AVOID IF HASHIMOTO''S

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Iodine is the rate-limiting substrate for thyroid hormone synthesis. In iodine-deficient populations, supplementation reverses hypothyroidism. In iodine-replete diets (Western populations using iodized salt, dairy, or seafood), supplementation is usually unnecessary. CRITICAL: iodine supplementation can worsen Hashimoto''s autoimmune destruction — test TPO antibodies first.^{[3, 4]}

Add if needed

Add these only if the foundation isn't enough.

L-Tyrosine

500-1000 mg morning, on empty stomach

morningempty stomach

L-tyrosine is the amino acid precursor to thyroid hormones T4 and T3. Useful for the fatigue and cognitive symptoms accompanying low-normal thyroid function. Activating; morning only. Modest evidence; effect is augmented when paired with adequate selenium and iodine.^{[5, 6]}

Vitamin B12 (Methylcobalamin)

1000 mcg daily, with breakfast

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B12 deficiency commonly accompanies hypothyroidism and amplifies fatigue and cognitive symptoms. Methylcobalamin bypasses methylation steps and is preferable to cyanocobalamin. Many hypothyroid patients feel better when B12 levels are optimized to the upper half of the reference range.^{[7, 8]}

Warnings

Do not take with: Levothyroxine (calcium, iron, and magnesium reduce absorption — space at least 4 hours apart). Lithium (selenium can interact mildly). MAOIs and stimulants with L-tyrosine. Amiodarone (iodine-containing — do not stack with supplemental iodine).

Do not take if: You have Hashimoto's thyroiditis or positive TPO antibodies (do NOT supplement iodine; use the Hashimoto's-specific protocol). You have hyperthyroidism or Graves' disease (this stack is contraindicated). You are pregnant or breastfeeding (iodine requirements increase but use prenatal vitamin formulations rather than separate iodine — coordinate with OB). You have severe kidney disease. Consult your endocrinologist before starting if you are on thyroid hormone replacement — coordinate any addition.

Lifestyle improvements

Distinguish autoimmune vs. non-autoimmune hypothyroidism

Test TPO antibodies before assuming iodine deficiency. Positive antibodies = Hashimoto''s = use that protocol, AVOID iodine. Negative antibodies + low T4 = consider iodine and selenium.

Get the right labs, not just TSH

TSH alone is insufficient. Full panel: TSH, free T4, free T3, reverse T3, TPO antibodies, thyroglobulin antibodies, urinary iodine if status is uncertain.

Adequate dietary iodine without mega-dosing

One daily serving of seafood, dairy, eggs, or iodized salt covers adequate iodine for most adults. Don''t mega-dose — both excess and deficiency cause thyroid dysfunction.

Reduce goitrogens during raw consumption

Cruciferous vegetables (broccoli, kale, cabbage) and soy contain goitrogens that interfere with iodine uptake when consumed raw in very large quantities. Cooking deactivates them. The "avoid cruciferous if thyroid" advice is overstated — moderate cooked intake is fine.

Sleep 7-9 hours

Hypothyroid symptoms are amplified by sleep deprivation.

Manage stress

Chronic cortisol elevation suppresses TSH and T4-to-T3 conversion.

Annual labs

TSH, free T4, free T3 yearly if you''re asymptomatic. Every 3-6 months when actively intervening or adjusting thyroid medications.

Find a thyroid-aware provider

Many primary care doctors only order TSH and miss subclinical issues. Look for an endocrinologist or integrative medicine doctor with explicit thyroid focus.

References

Selenium — supplement research overviewExamine.com link
Ventura M, et al. Selenium and Thyroid Disease: From Pathophysiology to Treatment. Int J Endocrinol. 2017;2017:1297658.PubMed link
Iodine — supplement research overviewExamine.com link
Leung AM, Braverman LE. Consequences of excess iodine. Nat Rev Endocrinol. 2014;10(3):136-142.PubMed link
L-Tyrosine — supplement research overviewExamine.com link
Jongkees BJ, et al. Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands. J Psychiatr Res. 2015;70:50-57.PubMed link
Vitamin B12 — supplement research overviewExamine.com link
Jabbar A, et al. Vitamin B12 deficiency common in primary hypothyroidism. J Pak Med Assoc. 2008;58(5):258-261.PubMed link

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Disclaimer: These statements have not been evaluated by the FDA. This protocol is educational, not a substitute for personalized medical advice. Talk to your doctor before starting any new supplement regimen — especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition. Last updated 5/20/2026.