Thyroid supplements: what works, what to avoid
Struggling with low energy, cold sensitivity, or slow weight loss? Before you add pills or powders, know which supplements actually help thyroid health and which ones can cause trouble. This page gives clear, practical advice you can use when talking to your doctor or pharmacist.
First, get the basics: a blood test. Ask for TSH, free T4, free T3 and thyroid antibodies if you suspect autoimmune thyroid disease. If you are already on thyroid replacement, never change doses or start a thyroid-support supplement without lab guidance. Small nutrient changes can shift your blood results and symptoms.
Key nutrients that can help
Selenium: Many people with autoimmune thyroid problems benefit from selenium. It supports thyroid hormone conversion and may lower antibody levels over months. Typical supplemental doses are 100–200 mcg daily, but check with your provider first.
Vitamin D: Low vitamin D is common and can worsen fatigue. A blood test (25‑OH vitamin D) will show if you need supplements. Typical corrective doses vary; follow lab results and medical advice.
Iodine: Essential for hormone production, but tricky. If you already have autoimmune thyroid disease, extra iodine can sometimes make inflammation worse. Do not take high-dose iodine without medical supervision.
Iron and zinc: Iron deficiency and low zinc can reduce thyroid function and energy. If labs show low ferritin or low zinc, supplements can help. Treat deficiencies based on test results, not guesswork.
B vitamins: B12 in particular is worth checking. Low B12 mimics many thyroid symptoms. If your B12 is low, supplements or injections can make a big difference.
When to be careful
Ashwagandha and other adaptogens: They’re popular because some can raise thyroid hormones. That sounds good, but if you take prescription levothyroxine or liothyronine, adaptogens can push your hormones too high. Use them only with a clinician’s approval.
Natural desiccated thyroid (NDT): NDT is a replacement drug, not a supplement. It contains T4 and T3. If you and your doctor switch from levothyroxine to NDT, doses change and labs must be monitored closely. Do not mix NDT with OTC “thyroid support” blends that promise hormone increases.
Herbal blends and unregulated products: Many online supplements make bold claims. They can contain undeclared hormones, heavy metals, or variable doses. Choose brands with third‑party testing and avoid products that guarantee “cure” or rapid weight loss.
Practical checklist before starting a thyroid supplement: get blood tests, review current meds, avoid high iodine unless directed, pick single-nutrient products when possible, and plan repeat labs in 6–12 weeks. Keep a symptom diary to track changes.
Want personalized advice? Talk to your primary care doctor, an endocrinologist, or a pharmacist. Simple testing and careful choices can make supplements helpful — or prevent harm.
Always list every supplement to your healthcare team, including brand names and doses. Keep current labels and note any side effects. If you notice rapid heartbeat, mood swings, or digestive changes after starting a supplement, stop and contact your clinician promptly for advice and testing today.
