What it is
Regulatory status: FDA-approved prescription thyroid-hormone replacement
Mechanism evidence: human
At a glance
What it is, why people use it, the evidence, and what to know before trying it.
Why people use it
- Thyroid-hormone replacement in hypothyroidism
Evidence at a glance
Levothyroxine is standard, evidence-based replacement for hypothyroidism when dosed to clinical and laboratory targets. It is not an anti-aging or weight-loss treatment in euthyroid people.
Confidence: strong
Clinical safety
Contraindications, interactions and clinical cautions from reviewed sources.
The boxed warning states thyroid hormones should not be used for obesity or weight loss. Excess replacement can cause arrhythmia, bone loss and hyperthyroid symptoms. Absorption is affected by food, calcium, iron and many medicines, so timing and monitoring must be individualized.
Forms and variants
This review does not automatically apply to:
- liothyronine
- desiccated thyroid
- combination T4/T3 products
Seen in protocols
Public protocols that include Levothyroxine. Open one to see the full context and source.