If Synthroid (levothyroxine) isn't working for you or you want a different formulation, there are real alternatives. Some give the same active hormone in another form. Others add T3 or come from animal thyroid. Each choice has trade-offs, so knowing the differences helps you talk with your doctor.
First, you’ll see four main groups: synthetic levothyroxine brands, combination T4/T3 therapies, pure T3 options, and natural desiccated thyroid (NDT). Compounded formulas exist too if you need custom doses or a pill form that’s easier to swallow. Below I explain each option and what to watch for.
Levothyroxine brands: Levoxyl, Euthyrox, Eltroxin, Tirosint and generic levothyroxine all deliver T4. Tirosint is a liquid/capsule with fewer additives, which can help if you have absorption issues or sensitivities to fillers. Generics cost less but can vary slightly between makers, so labs matter when you switch.
Combination T4/T3: Some doctors add liothyronine (Cytomel) to levothyroxine or prescribe combined products to give both T4 and T3. A few people feel better on a combo, but others get jittery or have heart palpitations. Timing and close monitoring are important.
Natural desiccated thyroid (NDT): Brands like Armour Thyroid, Nature-Throid or NP Thyroid come from porcine thyroid and contain both T4 and T3. Some patients prefer how they feel on NDT, but dose conversion and stability can be trickier. NDT isn’t ideal for everyone, especially if you need very predictable dosing.
Talk to your doctor before any change. Ask how the new dose compares to your current dose and when to recheck TSH and free T4/T3. Take thyroid meds the same way every day — on an empty stomach, 30–60 minutes before breakfast, or 3–4 hours after calcium or iron supplements. If you take proton pump inhibitors or have gut issues, mention that — absorption can change.
Watch symptoms as well as labs. Energy, sleep, weight and mood give useful clues. If you switch brands, recheck blood tests in 6–8 weeks. Pregnant people and those with heart disease need special care; dose changes can have bigger effects and require faster follow-up.
Many people worry about interactions and side effects. Foods and supplements like iron, calcium, soy and high‑fiber can cut how much levothyroxine you absorb. Take your pill at least four hours apart from those. Some doctors test free T3 and reverse T3 if symptoms stay despite normal TSH. Others try a low T3 add‑on for a short period. Keep a simple symptom log for two weeks before switching and share it with your clinician to speed safe, real adjustments and help find the best dose for you.
