Tirzepatide vs Semaglutide: Differences, Results and Side Effects

Tirzepatide vs Semaglutide: The Short Answer

Semaglutide (Ozempic, Wegovy and Rybelsus, available as weekly injections and daily tablets) activates one gut hormone receptor, GLP-1. Tirzepatide (Mounjaro, Zepbound) activates two, GIP and GLP-1. In SURMOUNT-5, a head-to-head trial of the two in adults with obesity who did not have type 2 diabetes, tirzepatide produced greater average weight loss than semaglutide. Both have a similar, mostly digestive side effect profile and carry the same boxed warning about thyroid C-cell tumors.

A trial average does not make one drug the right choice for everyone. Your medical history, other medications, the approved indication that fits your situation and how you tolerate treatment are weighed in an individual evaluation by a licensed provider.

How They Work: GLP-1 vs Dual GIP/GLP-1

Both medications mimic incretins, hormones the gut releases after eating. Activating the GLP-1 receptor slows stomach emptying, increases the feeling of fullness and helps the pancreas release insulin when blood sugar rises.

Tirzepatide also activates the GIP receptor, a second incretin pathway. Why adding GIP activity is associated with larger average weight loss in trials is still being studied. It is more accurate to say tirzepatide works through an additional pathway than to call it a stronger drug in every respect.

Side-by-side basics

Mounjaro vs Ozempic, Zepbound vs Wegovy: Brand Names and Approved Uses

Each active ingredient is sold under several brand names, and each brand has its own FDA-approved uses. Ozempic and Wegovy contain the same ingredient but are not interchangeable in purpose; the same is true of Mounjaro and Zepbound.

These labels have changed over time, and the approved patient groups (for example, age and weight criteria) are specific. Your provider should confirm the current prescribing information for any brand you are considering.

What about compounded versions?

Compounded semaglutide and tirzepatide are not FDA-approved, so the FDA has not reviewed them for safety, effectiveness or quality the way it reviews brand-name drugs. The FDA has issued safety communications about compounded versions, including reports of dosing errors. If you are offered a compounded product, ask what it contains, where it is made and how it is dosed.

Tirzepatide vs Semaglutide Weight Loss: What the Trials Show

Only a trial that tests the two medications against each other supports a direct comparison. Other well-known trials compared each drug with placebo, so their numbers cannot fairly be lined up side by side.

SURMOUNT-5: the head-to-head trial

SURMOUNT-5 enrolled adults with obesity who did not have type 2 diabetes and randomly assigned them to tirzepatide or semaglutide at weight-management doses. On average, participants taking tirzepatide lost more body weight than those taking semaglutide. After 72 weeks, average weight loss was 20.2% with tirzepatide (10 mg or 15 mg weekly) and 13.7% with semaglutide (1.7 mg or 2.4 mg weekly).

STEP 1 and SURMOUNT-1: separate placebo-controlled trials

STEP 1 tested semaglutide 2.4 mg against placebo in adults with obesity or overweight. SURMOUNT-1 tested tirzepatide against placebo in a similar but not identical population. Both found meaningful average weight loss compared with placebo.

Because these trials enrolled different participants and used different durations and designs, a percentage from one cannot be subtracted from a percentage in the other to rank the drugs. That is the question SURMOUNT-5 was designed to answer.

Comparing results from two different trials is like comparing race times run on different courses. The head-to-head trial is the fairer test.

Why averages are not promises

Trial results are averages. Some participants lost much more than the average, while others lost far less or stopped treatment because of side effects. No trial figure predicts how much an individual will lose.

Side Effects and Safety: What Is Similar and What Differs

Because both drugs act on the GLP-1 pathway, their side effect profiles overlap. Most side effects are digestive and are most common when treatment starts or the dose is increased.

Common side effects

• Nausea
• Diarrhea
• Vomiting
• Constipation
• Abdominal pain
• Decreased appetite

Serious warnings both labels share

• Boxed warning for thyroid C-cell tumors: these tumors were seen in rodent studies, and it is not known whether the risk applies to humans. Neither drug should be used by people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 (MEN 2).
• Pancreatitis: severe, persistent abdominal pain needs prompt medical attention.
• Gallbladder problems, including gallstones.
• Kidney problems linked to dehydration from vomiting or diarrhea.
• Low blood sugar, mainly when combined with insulin or sulfonylureas.
• Serious allergic reactions.

Differences worth knowing

• Oral birth control: tirzepatide labeling notes it may reduce the effectiveness of oral hormonal contraceptives, especially around the start of treatment and dose increases. Ask your provider about backup or non-oral options.
• Diabetic eye disease: both semaglutide and tirzepatide labels warn about diabetic retinopathy complications in people with type 2 diabetes, so people with existing retinopathy need monitoring.
• Pregnancy: if you are pregnant or planning a pregnancy, discuss timing with your provider before starting or continuing either drug.

No medication in this class is risk-free or suitable for everyone. Report new or worsening symptoms to your provider.

Which Is Better, Tirzepatide or Semaglutide? Factors a Provider Weighs

There is no single better drug for every patient. These are the factors a provider typically reviews with you:

• Approved indication: type 2 diabetes, obesity, cardiovascular disease and sleep apnea map to different brands.
• Medical history: thyroid cancer history, pancreatitis, gallbladder disease, kidney function and eye health.
• Other medications: insulin, sulfonylureas and oral contraceptives can change the plan.
• Past experience: how you tolerated a GLP-1 medication before, if you have taken one.
• Goals: expectations grounded in trial averages, not best-case results.
• Form: semaglutide is available as a daily tablet as well as a weekly injection, while tirzepatide is given only by injection.
• Cost and coverage: insurance coverage and out-of-pocket costs vary by brand and plan.

Suitability is decided at an in-person consultation with a licensed provider. Doses and dose increases are set individually and should not be planned from an article.

How AestheteMed Can Help in Hallandale Beach

AestheteMed offers medically supervised GLP-1 weight loss programs for adults in Hallandale Beach, Miami, Aventura and Fort Lauderdale. Details on each medication are on the semaglutide injection and tirzepatide injection pages.

Baseline blood work can help guide a weight loss plan. The clinic’s lab testing includes a weight loss panel covering CBC, CMP, thyroid markers (TSH, T3, T4), A1c and a lipid panel, and results are reviewed by a Medical Doctor or Nurse Practitioner. Whether either medication is appropriate for you is decided at your consultation, where program pricing is also confirmed.

The clinic is located at 2100 E Hallandale Beach Blvd, Suite 100, Hallandale Beach, FL 33009.

Frequently asked questions

Can I switch from semaglutide to tirzepatide?

Switching may be possible in some cases, but it is a decision for your prescribing provider. They will consider why you want to switch, how you responded to semaglutide and your current health. Do not change medications or doses on your own.

What happens if I stop taking tirzepatide or semaglutide?

Follow-up studies of both medications have reported that much of the lost weight tends to return after treatment stops, which is why they are generally discussed as long-term treatments alongside nutrition and activity changes. Talk with your provider before stopping so you can plan next steps.

Sources

• Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (SURMOUNT-5), NEJM 2025, PubMed
• WEGOVY prescribing information, FDA
• ZEPBOUND prescribing information, FDA
• MOUNJARO prescribing information, DailyMed