Synthroid alternatives: what to know
If Synthroid (levothyroxine) isn’t working for you or causes side effects, there are real options. Some people feel better on different brands or on a different form of thyroid hormone. Others try combination therapy or natural extracts. This guide lists common alternatives, how they differ, and practical steps to discuss with your doctor.
Medication options
Generic levothyroxine vs brand-name: Levothyroxine is the usual treatment. Different brands or generic manufacturers can vary slightly in absorption. If your labs are stable but symptoms persist after a switch, ask your clinician about trying a different brand or staying on a consistent product.
Liothyronine (T3): Liothyronine is the active thyroid hormone (T3). Doctors sometimes add it to levothyroxine for people who still feel unwell on T4-only therapy. It works faster but can cause jitteriness, palpitations, or bone loss if misused. Dosing is tricky and needs close monitoring.
Combination T4/T3 products: Some prescriptions combine levothyroxine and liothyronine in a fixed ratio. Patients report better energy and mood, but evidence is mixed. Your doctor may try a slow, monitored trial.
Natural desiccated thyroid (NDT): NDT comes from pig thyroid and contains both T4 and T3. Some people prefer it because they feel symptom relief. Dosing differs and lab targets are the same; expect to adjust carefully and monitor regularly.
Compounded thyroid: Pharmacies can make custom mixes of T4 and T3. This can help if you need unusual ratios, but quality varies. Use a reputable compounding pharmacy and monitor labs.
Practical tips for switching
Get the right tests: Ask for TSH and free T4 at minimum. If you’re changing therapy, add free T3 when appropriate. Don’t rely only on symptoms; labs guide safe adjustments.
Change one thing at a time: Switch only one variable—brand, formulation, or dose—then wait 6–8 weeks to recheck labs. That makes it easier to see what helped.
Watch interactions: Calcium, iron, soy, and some meds can block levothyroxine absorption. Take thyroid meds on an empty stomach and separate supplements by several hours.
Know the risks: Faster-acting T3 can improve symptoms but may raise heart rate or reduce bone density. NDT has variable hormone content and is less predictable.
Talk to your clinician: Say exactly what symptoms bother you. Bring a medication list and recent labs. If you want a trial of T3 or NDT, ask about monitoring frequency and clear stop criteria.
Special situations matter. If you're pregnant or trying to conceive, doctors usually stick with levothyroxine because it's predictable and safe for the baby; dose needs often rise during pregnancy and labs should be checked every 4 weeks early on. If you have heart disease, slower changes and lower starting doses reduce risk. Older adults may need lower doses. Always tell your provider about pregnancy plans, heart issues, or osteoporosis before changing thyroid meds.
Keep notes of your symptoms.
