Understanding the Different Types of Thyroid Medications

Amanda Alviz, FNP
Sep 1
3 min read

When it comes to treating thyroid conditions, one size does not fit all. The thyroid gland plays a key role in regulating metabolism, energy, and overall hormonal balance. If it isn’t functioning properly—whether underactive (hypothyroidism) or overactive (hyperthyroidism)—medications can help restore balance. But not all thyroid medications are the same. Here’s a breakdown of the most common types and how they work.

1. Levothyroxine (Synthetic T4)

Levothyroxine is the most commonly prescribed thyroid medication. It’s a synthetic form of thyroxine (T4), the hormone naturally made by the thyroid gland.

How it works: Your body converts T4 into the active hormone T3 (triiodothyronine) as needed.
Brand names: Synthroid®, Levoxyl®, Tirosint®
Who it’s for: In conventional medicine, most people with hypothyroidism are started on this medication.
Considerations: Absorption can vary depending on gut health, other medications, or even the time of day it’s taken. If your body does not convert T4 to the active thyroid hormone (T3) efficiently, you may continue to have hypothyroidism symptoms despite treatment.

2. Liothyronine (Synthetic T3)

Liothyronine is a synthetic form of T3, the active thyroid hormone.

How it works: Provides direct T3 to the body, bypassing the need for T4-to-T3 conversion.
Brand name: Cytomel®
Who it’s for: Patients who don’t feel well on T4-only medication, especially if they have trouble converting T4 into T3.
Considerations: Shorter half-life means it may require multiple daily doses, and it can sometimes cause palpitations or anxiety in sensitive individuals.

3. Combination T4/T3 Therapy

Some people do better with a mix of T4 and T3, either through a compounded prescription or a natural desiccated thyroid medication.

Why: Mimics the thyroid’s natural output more closely than T4 alone.
Options: Compounded T4/T3 (customized by a pharmacy) or natural desiccated thyroid (see below).
Considerations: May help improve symptoms like fatigue, brain fog, and weight struggles if T4 alone isn’t enough.

4. Natural Desiccated Thyroid (NDT)

NDT comes from the dried thyroid glands of pigs and contains a blend of T4, T3, T2, and other thyroid components.

Brand names: Armour®, NP Thyroid®, Nature-Throid®
How it works: Provides both T4 and T3 (and small amounts of other thyroid hormones).
Who it’s for: Some people prefer a more “natural” approach and report better symptom relief on NDT.
Considerations: Can be harder to dose consistently since hormone content can vary slightly. Not always the first choice in conventional medicine. You may be told by your provider that they will not prescribe this medication for you because the are either not familiar with it or because they have not been formally FDA approved.

5. Antithyroid Medications (for Hyperthyroidism)

When the thyroid is overactive (as in Graves’ disease or toxic nodules), medications that block thyroid hormone production may be used.

Examples: Methimazole (Tapazole®), Propylthiouracil (PTU)
How they work: Reduce the thyroid’s ability to produce hormones.
Considerations: Often used short-term, or as a bridge to definitive treatment.

6. Low-Dose Naltrexone (LDN)

Low-dose naltrexone (LDN) is a unique therapy that works very differently from standard thyroid medications but is sometimes used alongside them in functional medicine.

How it works: At very small doses, LDN temporarily blocks opioid receptors, which stimulates the body to produce more of its own endorphins and enkephalins. These natural chemicals help regulate immune function, reduce inflammation, and modulate pain.
Who it’s for: Patients with autoimmune conditions (like Hashimoto’s thyroiditis or Grave's Disease), chronic pain, or fatigue may benefit from its immune-balancing effects.
Considerations: LDN is generally well-tolerated, but it is considered “off-label,” meaning it isn’t FDA-approved specifically for these uses. Dosing is much lower than what’s used for opioid dependence, and it usually requires a compounding pharmacy.

7. Other Supportive Therapies

While not thyroid hormone replacements, certain medications or supplements may be used alongside treatment:

Beta-blockers: To calm heart rate and anxiety in hyperthyroidism.
Nutrient support: Selenium, zinc, iron, and iodine (when appropriate) support healthy thyroid function.
Lifestyle: Stress management, gut health, and adrenal support play big roles in how well thyroid medications work.

Final Thoughts

Finding the right thyroid medication—and the right dose—often takes time and personalized care. Some people thrive on standard levothyroxine, while others need T3 support or natural desiccated thyroid. If you’re still experiencing fatigue, weight gain, or brain fog despite treatment, it may be worth discussing alternative thyroid medication options with a knowledgeable provider.