Tirzepatide vs Semaglutide: How These Weight Loss Medications Compare

Tirzepatide and semaglutide are both GLP-1 receptor agonist medications. FDA-approved versions include Mounjaro/Zepbound (tirzepatide) and Wegovy/Ozempic (semaglutide). Important: Compounded versions of these medications are NOT FDA-approved. The FDA does not review or verify the safety, effectiveness, or quality of compounded medications. The clinical trial data discussed below comes from studies of the FDA-approved brand-name products only and may not apply to compounded versions. Individual results vary and are not guaranteed. Decisions about whether either medication is appropriate for you should be made with a licensed healthcare provider.

This comparison covers what the published trials of the approved products show about tirzepatide and semaglutide, plus how they differ in mechanism, dosing, and FDA status, to help you have an informed conversation with a clinician about which option may be right for you.

Quick Overview: Key Differences

The table below summarizes factual differences in mechanism, dosing schedule, and FDA status, along with the average weight-loss figures reported in the trials of the FDA-approved branded products. Those trial figures reflect the approved drugs studied under controlled conditions, not compounded versions, and individual results vary.

Factor	Tirzepatide (Mounjaro/Zepbound)	Semaglutide (Wegovy/Ozempic)
Average Weight Loss in Branded-Product Trials	About 20.9% of body weight at the 15 mg dose in SURMOUNT-1 (approved-drug trial; may not apply to compounded; individual results vary)	About 15% of body weight at the 2.4 mg dose in STEP 1 (approved-drug trial; may not apply to compounded; individual results vary)
Mechanism	Dual GLP-1 and GIP agonist	Single GLP-1 agonist
Dosing	Once weekly injection	Once weekly injection
FDA Approval for Weight Loss	Zepbound (2023)	Wegovy (2021)
GI Side Effects in Branded-Product Trials	Reported somewhat more frequently in SURMOUNT-1 than semaglutide in STEP 1	Reported at moderate frequency in STEP 1
Brand-Name Cost	Varies by pharmacy and plan	Varies by pharmacy and plan
Compounded Program Cost	$299/month (see product page for current pricing)	$149/month (see product page for current pricing)
Time on Market (branded)	Newer (Mounjaro approved 2022)	Longer track record (Ozempic approved 2017)

What Are Tirzepatide and Semaglutide?

Semaglutide (Wegovy, Ozempic, Rybelsus)

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist originally approved for type 2 diabetes in 2017 (Ozempic) and subsequently approved for chronic weight management in 2021 (Wegovy) (Source: FDA).

Available forms:

• Injectable: Ozempic (diabetes), Wegovy (weight loss)
• Oral tablet: Rybelsus (diabetes)
• Compounded injectable (not FDA-approved): various strengths

For comprehensive information about semaglutide, see our complete semaglutide guide.

Tirzepatide (Mounjaro, Zepbound)

Tirzepatide is a dual glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptor agonist approved for type 2 diabetes in 2022 (Mounjaro) and for chronic weight management in 2023 (Zepbound) (Source: FDA).

Available forms:

• Injectable: Mounjaro (diabetes), Zepbound (weight loss)
• Compounded injectable (not FDA-approved): various strengths
• No oral form currently available

The Key Difference: Dual vs Single Mechanism

The fundamental difference between these medications lies in their mechanism:

• Semaglutide: Activates only GLP-1 receptors
• Tirzepatide: Activates both GLP-1 and GIP receptors

Both medications work through pathways that reduce appetite and support metabolic health. In trials of the FDA-approved products, this difference in mechanism corresponded to differences in average weight loss, as described below.

How They Work

Shared Mechanisms (GLP-1 Effects)

Both medications activate GLP-1 receptors, which leads to:

• Appetite suppression: Signals to the brain that you’re full, reducing hunger
• Delayed gastric emptying: Food stays in your stomach longer, prolonging satiety
• Blood sugar regulation: Increases insulin when blood sugar is high, reduces glucagon
• Reduced food cravings: Decreases desire for high-calorie foods

Tirzepatide’s Additional GIP Action

Tirzepatide’s activation of GIP receptors adds several effects studied in the approved product:

• Enhanced insulin sensitivity: Cells respond better to insulin
• Improved fat metabolism: Better breakdown and utilization of stored fat
• Additional appetite regulation: Works through complementary pathways
• Potential metabolic benefits: May have additional effects on metabolism beyond GLP-1 alone

In the trials of the FDA-approved products, combined GIP and GLP-1 activation was associated with greater average weight loss than GLP-1 activation alone (Source: SURMOUNT-1 Trial, NEJM). These findings come from studies of the approved drug and may not apply to compounded versions.

What the Branded-Product Trials Showed

The figures in this section come from published clinical trials of the FDA-approved branded products (Zepbound/Mounjaro and Wegovy/Ozempic). They describe results observed in those trials, not compounded versions. The FDA has not reviewed compounded tirzepatide or semaglutide for safety or effectiveness, and the trial results below may not apply to them. Individual results vary and are not guaranteed.

Clinical Trial Results

Tirzepatide (SURMOUNT-1 Trial, 72 weeks)

In SURMOUNT-1, a trial of FDA-approved tirzepatide, participants experienced the following average results. These figures are from the approved-drug trial and may not apply to compounded tirzepatide; individual results vary and are not guaranteed.

15 mg dose (highest maintenance dose):

• Average weight loss: 20.9% of total body weight
• ≥5% weight loss: 91% of participants
• ≥10% weight loss: 83% of participants
• ≥15% weight loss: 71% of participants
• ≥20% weight loss: 57% of participants
• ≥25% weight loss: 40% of participants

10 mg dose:

• Average weight loss: 19.5% of total body weight

5 mg dose (lowest maintenance dose):

• Average weight loss: 15.0% of total body weight

Source: SURMOUNT-1 Clinical Trial, New England Journal of Medicine

Semaglutide (STEP 1 Trial, 68 weeks)

In STEP 1, a trial of FDA-approved semaglutide, participants experienced the following average results. These figures are from the approved-drug trial and may not apply to compounded semaglutide; individual results vary and are not guaranteed.

2.4 mg dose (maintenance dose):

• Average weight loss: 14.9% of total body weight
• ≥5% weight loss: 86% of participants
• ≥10% weight loss: 69% of participants
• ≥15% weight loss: 50% of participants
• ≥20% weight loss: 32% of participants

Source: STEP 1 Clinical Trial, New England Journal of Medicine

How the Two Branded-Product Trials Compare

SURMOUNT-1 (tirzepatide) and STEP 1 (semaglutide) were separate trials, not a single head-to-head study, so cross-trial comparisons should be interpreted with caution. A direct head-to-head trial of the FDA-approved branded products, SURMOUNT-5, compared the two drugs and found that tirzepatide produced greater average weight loss than semaglutide (Source: SURMOUNT-5 Trial, NEJM 2025). These results are from studies of the approved drugs, not compounded versions, and individual results vary.

Weight Loss Milestone	Tirzepatide 15mg (SURMOUNT-1)	Semaglutide 2.4mg (STEP 1)
Average Total	20.9%	14.9%
≥5% Loss	91%	86%
≥10% Loss	83%	69%
≥15% Loss	71%	50%
≥20% Loss	57%	32%

Figures reflect the trials of the FDA-approved branded products noted in each column. They may not apply to compounded versions. Individual results vary and are not guaranteed.

What This Means in Practice

In the head-to-head trial of the FDA-approved branded products (SURMOUNT-5), tirzepatide produced greater average weight loss than semaglutide (Source: SURMOUNT-5 Trial, NEJM 2025). These results are from studies of the approved drugs, not compounded versions, and individual results vary. Some people may respond differently to either medication, and factors such as tolerability, cost, and availability also matter. A licensed clinician can help you weigh these factors for your situation.

Side Effects in the Branded-Product Trials

The side-effect rates below come from trials of the FDA-approved branded products (SURMOUNT-1 for tirzepatide, STEP 1 for semaglutide). Because these were separate trials, the numbers are not a direct head-to-head safety comparison. Compounded versions of these medications have not undergone FDA review for safety, effectiveness, or quality, so these figures may not reflect the safety profile of compounded products. All GLP-1 medications carry material risks; review them with your provider before starting.

Gastrointestinal Side Effects

Gastrointestinal effects were the most commonly reported side effects in both branded-product trials.

Side Effect	Tirzepatide 15mg (SURMOUNT-1)	Semaglutide 2.4mg (STEP 1)
Nausea	33%	20-30%
Diarrhea	23%	15-20%
Vomiting	12%	8-12%
Constipation	11%	10-15%
Abdominal Pain	9%	5-10%

Discontinuation Due to Side Effects

• Tirzepatide: 6.2% of participants discontinued due to adverse events in SURMOUNT-1
• Semaglutide: 4.5% of participants discontinued due to adverse events in STEP 1

In these separate branded-product trials, tirzepatide had a somewhat higher reported frequency of GI side effects and discontinuations than semaglutide.

Managing Side Effects

General strategies that clinicians often discuss for GLP-1 medications include:

• Starting at a low dose and increasing gradually under medical supervision
• Eating smaller, more frequent meals
• Avoiding fatty, greasy, or spicy foods
• Staying well-hydrated
• Reporting persistent or severe symptoms to your provider

For more on managing side effects, see our guide to managing semaglutide side effects. Always follow the guidance of your own healthcare provider.

Serious Side Effects

Both medications carry warnings for rare but serious risks. These are material risks that should be reviewed with a clinician before starting treatment:

• Pancreatitis: Seek immediate medical attention for severe abdominal pain
• Gallbladder issues: Rapid weight loss can increase gallstone risk
• Thyroid C-cell tumors: Boxed warning based on rodent studies; risk in humans is not determined. Not for people with a personal or family history of medullary thyroid carcinoma or MEN 2
• Diabetic retinopathy: Possible worsening in people with existing eye disease
• Kidney problems: Dehydration from GI side effects can worsen kidney function

Because compounded versions are not FDA-approved and have not undergone FDA safety review, their risk profile has not been independently verified by the FDA. Discuss all potential risks with a licensed provider.

Tolerability in the Branded-Product Trials

In SURMOUNT-1 and STEP 1, the branded products had broadly similar categories of side effects, with tirzepatide showing somewhat higher reported rates of nausea, diarrhea, and discontinuation. These are separate trials, not a direct head-to-head comparison, and tolerability varies from person to person.

Dosing and Administration

The titration schedules below reflect the FDA-approved prescribing information for the branded products. Compounded products may be dosed differently; always follow your provider’s specific instructions.

Tirzepatide Dosing Schedule (Zepbound, branded)

Timeframe	Dose	Purpose
Weeks 1-4	2.5 mg weekly	Initiation dose
Weeks 5-8	5 mg weekly	First increase (minimum maintenance dose)
Weeks 9-12	7.5 mg weekly	Second increase
Weeks 13-16	10 mg weekly	Third increase
Weeks 17-20	12.5 mg weekly	Fourth increase
Week 21+	15 mg weekly	Maximum maintenance dose

Source: Zepbound Prescribing Information, FDA

Semaglutide Dosing Schedule (Wegovy, branded)

Timeframe	Dose	Purpose
Weeks 1-4	0.25 mg weekly	Initiation dose
Weeks 5-8	0.5 mg weekly	First increase
Weeks 9-12	1.0 mg weekly	Second increase
Weeks 13-16	1.7 mg weekly	Third increase
Week 17+	2.4 mg weekly	Maintenance dose

Key Dosing Differences

• Escalation period: Branded tirzepatide takes about 20 weeks to reach max dose vs about 16 weeks for branded semaglutide
• Number of doses: Tirzepatide has 6 dose levels vs 5 for semaglutide
• Flexibility: Both allow staying at lower doses if tolerated and effective, at a provider’s discretion
• Administration: Both are once-weekly subcutaneous injections

Weight Loss Timeline

The ranges below are general illustrations of how weight loss tends to unfold over time and are not predictions of any individual’s results. They are not guarantees, and your experience may differ. Compounded products have not been studied for these timelines.

Tirzepatide Timeline (general illustration)

• Month 1: typically modest, while at low starting doses
• Month 3: often continued gradual loss
• Month 6: often continued loss as the dose increases
• Month 12: in the SURMOUNT-1 branded-product trial, average loss approached the figures cited above
• Month 18: weight loss in trials of the branded product generally plateaued

Semaglutide Timeline (general illustration)

• Month 1: typically modest, while at low starting doses
• Month 3: often continued gradual loss
• Month 6: often continued loss as the dose increases
• Month 12: in the STEP 1 branded-product trial, average loss approached the figures cited above
• Month 18: weight loss in trials of the branded product generally plateaued

For a detailed week-by-week semaglutide timeline, see our complete timeline guide.

Time to Peak Results in the Branded-Product Trials

• Tirzepatide: In SURMOUNT-1, average weight loss continued through roughly 72 weeks before plateauing
• Semaglutide: In STEP 1, average weight loss continued through roughly 60-68 weeks before plateauing

Cost Comparison

Brand-Name Pricing

Brand-name pricing for Zepbound, Mounjaro, Wegovy, and Ozempic varies by pharmacy, region, and insurance. Manufacturer savings programs may be available for eligible patients. Check current pricing with the pharmacy and your plan.

Contour Compounded Program Pricing

Program	Monthly Cost
Compounded tirzepatide program	$299/month (see product page for current pricing)
Compounded semaglutide program	$149/month (see product page for current pricing)

Insurance Coverage

• For diabetes: Branded Mounjaro and Ozempic are often covered, with copays varying by plan
• For weight loss: Coverage for branded Zepbound and Wegovy is limited; many plans exclude weight loss medications
• Compounded medications: Generally not covered by insurance

For more on cost considerations, see our semaglutide cost guide.

Factors to Discuss With Your Provider

There is no single “better” medication for everyone. The right choice depends on your medical history, goals, tolerability, and access, and should be made with a licensed healthcare provider. The points below are factors to discuss, not recommendations.

Reasons a provider might consider tirzepatide

• In the head-to-head branded-product trial (SURMOUNT-5), tirzepatide produced greater average weight loss than semaglutide (Source: SURMOUNT-5 Trial, NEJM 2025); these results are from the approved drugs, may not apply to compounded, and individual results vary
• You have type 2 diabetes alongside obesity (discuss with your provider)
• You previously tolerated semaglutide but did not reach your goals

Reasons a provider might consider semaglutide

• You are particularly concerned about GI side effects; in the branded-product trials, semaglutide had somewhat lower reported rates
• You prefer a medication with a longer time on the market (branded semaglutide since 2017)
• An oral option matters to you (Rybelsus is an oral form of semaglutide; tirzepatide has no oral form)

Either medication may be considered if:

• You meet clinical criteria your provider uses (for example, BMI ≥30, or BMI ≥27 with weight-related conditions)
• Other weight management approaches have not met your goals
• You are prepared for long-term, clinician-directed treatment
• You are willing to make lifestyle changes alongside medication
• You do not have contraindications (such as a personal or family history of medullary thyroid carcinoma or MEN 2)

Whether either of these medications is appropriate for you is a decision for you and a licensed clinician.

Availability and Access

How to Access Each Medication

Brand-name options:

• Prescription from your doctor or specialist
• Telehealth services for eligible weight management indications
• Fill at a retail or specialty pharmacy
• Apply manufacturer savings programs if eligible

Compounded options:

• Available through some telehealth platforms following a provider evaluation
• Prescription required from a licensed provider
• Not FDA-approved; the FDA does not verify the safety, effectiveness, or quality of compounded medications
• Typically includes ongoing medical oversight

Our programs offer clinician-directed compounded semaglutide and compounded tirzepatide with ongoing medical support. These compounded medications are not FDA-approved.

Switching Between Medications

Switching between GLP-1 medications should be done only under the direction of a licensed provider, who will determine timing and dosing for your situation. The general descriptions below are educational and are not medical advice or instructions to follow on your own.

Semaglutide to Tirzepatide

Some patients switch from semaglutide to tirzepatide under provider direction. A provider may:

• Advise when to take the last semaglutide dose
• Determine an appropriate gap before starting tirzepatide
• Start tirzepatide at an initiation dose and titrate per the prescribing information
• Monitor for renewed GI symptoms during the transition

Tirzepatide to Semaglutide

Less common, and sometimes considered due to side effects, cost, supply, or coverage changes. As with any switch, timing and dosing should be directed by your provider.

Frequently Asked Questions

Which medication produced more weight loss in clinical trials?

In the head-to-head trial of the FDA-approved branded products (SURMOUNT-5), tirzepatide produced greater average weight loss than semaglutide (Source: SURMOUNT-5 Trial, NEJM 2025). In their individual pivotal trials, tirzepatide (SURMOUNT-1) showed an average of about 20.9% at the 15 mg dose and semaglutide (STEP 1) about 15% at the 2.4 mg dose. These results are from studies of the approved drugs, not compounded versions, and individual results vary and are not guaranteed.

Is tirzepatide safer than semaglutide?

Neither product has been shown to be “safer” than the other in a way that applies to everyone. In their separate branded-product trials, both had broadly similar categories of side effects, with tirzepatide showing somewhat higher reported rates of nausea, diarrhea, and discontinuation. Both carry serious warnings, including a boxed warning related to thyroid C-cell tumors. Compounded versions have not undergone FDA safety review. A licensed provider can assess which option, if any, is appropriate for you.

Which medication costs less?

Costs vary by product, pharmacy, plan, and program. Branded pricing depends on insurance and manufacturer savings programs. For Contour’s compounded program pricing, see current pricing on our product page. Compounded medications are generally not covered by insurance.

Can I switch from semaglutide to tirzepatide?

Some patients switch under the direction of a licensed provider, who determines appropriate timing and dosing. Do not change medications on your own. Talk with your provider about whether switching is appropriate for you.

Does tirzepatide have more side effects?

In the separate branded-product trials, tirzepatide had somewhat higher reported rates of certain GI side effects (for example, nausea at 33% in SURMOUNT-1 vs 20-30% in STEP 1) and a somewhat higher discontinuation rate (6.2% vs 4.5%). These were not head-to-head trials, individual tolerability varies, and these figures may not apply to compounded versions.

Is tirzepatide FDA approved for weight loss?

Yes. The branded product tirzepatide was approved by the FDA for chronic weight management under the name Zepbound in 2023, and for type 2 diabetes under the name Mounjaro in 2022. Compounded tirzepatide is not FDA-approved.

Can I take both medications together?

No. You should not combine tirzepatide and semaglutide. They work through overlapping GLP-1 pathways, and combining them could increase the risk of side effects without added benefit. Use only one GLP-1 medication, as directed by your provider.

Which is better for diabetes control?

Both branded products are used to help manage blood sugar in type 2 diabetes. The choice depends on your individual situation and should be made with your provider. This article focuses on weight management; diabetes treatment decisions belong with your clinician.

Will insurance cover tirzepatide or semaglutide?

Coverage varies. For diabetes (Mounjaro/Ozempic), branded coverage is common with copays that vary by plan. For weight loss (Zepbound/Wegovy), branded coverage is limited and many plans exclude weight loss medications. Compounded medications are generally not covered. Check your specific plan.

References

• Aronne LJ, et al. “Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.” New England Journal of Medicine. 2025. doi:10.1056/NEJMoa2416394. https://www.nejm.org/doi/abs/10.1056/NEJMoa2416394 (SURMOUNT-5 head-to-head trial of the FDA-approved branded products)