The short answer
Take levothyroxine at least 60 minutes before any GLP-1 dose. Recheck TSH at 6-8 weeks after starting a GLP-1.
Use with cautionGenerally OK with monitoring
Why it matters
Delayed gastric emptying reduces levothyroxine Cmax and bioavailability, particularly when both are taken in the morning.
What to do
Take levothyroxine 60+ minutes before breakfast and any GLP-1 dose. Recheck TSH 6-8 weeks after starting the GLP-1 and after each dose escalation. Adjust levothyroxine dose only on the basis of TSH change, not symptoms.
Ask your prescriber
“I take Levothyroxine. Is Wegovy safe with it, and what should we monitor?”
How Levothyroxine and Wegovy interact
Delayed gastric emptying reduces levothyroxine Cmax and bioavailability, particularly when both are taken in the morning.
What to do
Take levothyroxine 60+ minutes before breakfast and any GLP-1 dose. Recheck TSH 6-8 weeks after starting the GLP-1 and after each dose escalation. Adjust levothyroxine dose only on the basis of TSH change, not symptoms.
Before you start Wegovy
A licensed prescriber reviews your full medication and supplement list before prescribing a GLP-1. If you take Levothyroxine, mention it at your consultation.
Compare telehealth providersWe earn affiliate commissions from listed providers. Rankings are based on patient-reported outcomes, not commissions. See our editorial standards.
Same question, other GLP-1s
Other things people check with Wegovy
Full Levothyroxine interaction profile
See Levothyroxine reviewed against every GLP-1 on one page: Levothyroxine + GLP-1 interactions
Sources
Educational information, not medical advice. Always confirm interactions with your prescriber or pharmacist.
Common questions readers ask
- Can you drink alcohol on Wegovy?
- No hard contraindication, but alcohol tolerance often drops sharply on GLP-1. Many patients also report reduced desire for alcohol — likely a secondary effect of GLP-1 on the brain reward system. Full evidence-graded answer
- Can I take GLP-1 while pregnant?
- No. All FDA-approved GLP-1s carry a pregnancy contraindication. Stop GLP-1 at least 2 months before planned conception due to its long half-life. Full evidence-graded answer
- Is it safe to take GLP-1 long-term?
- Liraglutide has 15+ years of post-marketing data (Victoza approved 2010). Semaglutide has 8+ years (Ozempic approved 2017). No new class-wide safety signals have emerged in extended follow-up. Chronic use is the FDA-approved indication for both T2D and obesity. Full evidence-graded answer
- What happens if I miss a weekly GLP-1 dose?
- If within 5 days: take the missed dose as soon as you remember, then resume the regular schedule. More than 5 days late: skip it and inject your next scheduled dose. Never double up. Full evidence-graded answer
- Can GLP-1 cause thyroid cancer?
- The boxed warning is based on rodent studies showing medullary thyroid carcinoma (MTC) in mice and rats. No human cases have been attributed to GLP-1 use despite 10+ years post-approval surveillance. Full evidence-graded answer