T3/T4 (Combination Thyroid): How It Works, What It's Studied For & Safety
T3/T4 (Combination Thyroid) is compounded combination thyroid preparations containing both liothyronine (T3) and levothyroxine (T4) at clinician-specified ratios, used as an alternative to T4-only therapy. Clinicians consider it for hypothyroidism in patients who report incomplete symptom resolution on levothyroxine alone. Compounded variants are dispensed by Wells Pharmacy Network only after a clinician evaluation.
Also known as: Liothyronine + Levothyroxine, Compounded T3/T4
How does T3/T4 (Combination Thyroid) work?
T4 is the long-acting prohormone; T3 is the active hormone at peripheral receptors. Combination therapy is studied for patients whose deiodinase function or symptom resolution does not match a T4-only regimen.
What is T3/T4 (Combination Thyroid) studied for?
- Hypothyroidism in patients who report incomplete symptom resolution on levothyroxine alone
- Clinician-directed personalized thyroid replacement
How is T3/T4 (Combination Thyroid) taken?
Compounded oral capsules at clinician-specified T4:T3 ratios. The individual ingredients are FDA-approved as separate finished products.
Is T3/T4 (Combination Thyroid) FDA-approved? Is it safe?
FDA-approved as a finished drug product when prescribed under its labeled indications. Compounded variants on this site are separate from the branded product and are dispensed only when a clinician determines a compounded preparation is appropriate. Cardiac risk increases with T3 over-replacement; baseline EKG is appropriate in older adults. Compounded prescription-only preparations are dispensed by Wells Pharmacy Network. Eligibility is decided by a licensed clinician based on intake and labs, not by checkout. Compounded products on this site are not FDA-approved and are not generic equivalents of any branded medication.
In the Regen Therapy catalog
This compound does not currently appear in an active Regen Therapy protocol. Browse the full catalog for adjacent options.
What does the research say about T3/T4 (Combination Thyroid)?
Mixed RCT evidence; ATA guidelines acknowledge selected combination-therapy use in non-responders.
Citations & further reading
Considering T3/T4 (Combination Thyroid) as part of a protocol?
Browse Regen Therapy's catalog or start a clinician evaluation. Every prescription is reviewed by a licensed clinician and dispensed by Wells Pharmacy Network.
Browse the catalog →