Natural Desiccated Thyroid (NDT): What to Know Before You Try It
Natural Desiccated Thyroid, often called NDT, comes from dehydrated pig thyroid gland. It contains both T4 and T3 hormones in fixed ratios, unlike levothyroxine which is mostly T4. Some people say NDT helps symptoms that didn’t improve on levothyroxine — more energy, clearer thinking, or less weight gain. Other folks switch back because of side effects or lab surprises. Here’s a practical, no-nonsense look at how NDT works, what to watch for, and how to use it safely.
How NDT works
NDT supplies thyroid hormones the body needs: thyroxine (T4) and triiodothyronine (T3). The T3 in NDT acts faster and is more active than T4, which some patients find helpful. Because NDT mixes hormones in a fixed ratio, blood levels can change differently than when taking only T4. That means symptoms and lab tests (TSH, free T4, free T3) can shift more quickly after dose changes.
Brands you’ll hear about include Armour Thyroid, Nature-Throid, and NP Thyroid. These are prescription products in most countries. Quality varies between brands and batches, so careful monitoring matters.
Practical tips and safety
Start low and go slow. If you switch from levothyroxine, your doctor may lower the starting dose because NDT has active T3. Check TSH and symptoms 6–8 weeks after any change. If you feel palpitations, anxiety, or heat intolerance, the dose may be too high.
Watch for heart and bone effects. Too much thyroid hormone can increase heart rate, cause irregular beats, or speed bone loss. People with heart disease, osteoporosis, or uncontrolled adrenal problems should be cautious and stay under medical care.
Pregnancy and breastfeeding need special attention. Thyroid needs change during pregnancy; many doctors prefer levothyroxine because it’s easier to fine-tune. If you’re pregnant or planning to be, talk to your clinician before switching.
Don't order NDT from random online shops without a prescription. Fake or low-quality products are a risk. Use a licensed pharmacy and get regular lab checks. If cost is a concern, ask your prescriber about options or patient-assistance programs.
Keep a symptom log. Note energy, sleep, mood, weight, and any palpitations. That record helps your provider adjust dose more precisely than labs alone.
Final practical note: some people do better on NDT, others don’t. The difference often comes down to individual response, careful dosing, and follow-up. Talk openly with your clinician, bring your lab results, and focus on steady improvements rather than immediate fixes.
