Tirzepatide vs. semaglutide: how the two medications differ

Both are weekly injections used in weight loss care. They act on different hormone receptors, and a clinician decides which one, if either, fits you.

Tirzepatide and semaglutide are the two medications most people mean when they say GLP-1. They are often mentioned together, and they are not the same medication.

Here is what the official sources say about each one, and what that means when you start care.

What they have in common

Both are injected under the skin once a week. Both are started at a low dose that is raised step by step: the National Library of Medicine's patient pages say a doctor will probably start a patient on a low dose and increase it.

The FDA-approved versions of both are approved for use together with a reduced calorie diet and increased physical activity. Neither one replaces those.

How they act

Semaglutide is a GLP-1 receptor agonist: it acts on the receptor of GLP-1, a hormone secreted from the intestine.

Tirzepatide acts on two receptors. In its approval announcement the FDA describes it as activating the receptors of two hormones secreted from the intestine, GLP-1 and GIP, to reduce appetite and food intake.

That is the real difference between them: one target for semaglutide, two for tirzepatide.

Who the FDA-approved versions are for

The FDA approved tirzepatide for chronic weight management, under the brand name Zepbound, for adults with obesity (a body mass index of 30 or greater) or overweight (27 or greater) with at least one weight-related condition.

The prescribing information of Wegovy, the semaglutide approved for chronic weight management, names the same two thresholds: 30 or greater, or 27 or greater with at least one weight-related condition.

Side effects

The FDA's announcement for tirzepatide lists nausea, diarrhea, vomiting, constipation and stomach discomfort among its side effects. Like any prescription treatment, GLP-1 medications can have side effects; the most commonly reported include nausea, reduced appetite and digestive changes.

Tell your clinician about your health history and the medications you take before you start, and message your care team about anything that worries you. For a medical emergency, call 911.

Which one is right for you

That is a clinician's decision, made from your health history, the medications you have taken before and your goals. Results vary from person to person, and nobody can promise a number.

At neo, an independent licensed clinician reviews your online assessment and decides whether treatment is appropriate, with which medication and at what dose. The medications prescribed through neo are compounded. Compounded medications are not FDA approved and are not the same as brand-name medications.

This article is general information, not medical advice. A licensed clinician decides whether a medication is appropriate for you.