Semaglutide vs. tirzepatide: weight loss, risks, and product differences

01 · Continued

What the direct weight-loss study found.: more detail

The closest direct weight-loss study compared injectable semaglutide with injectable tirzepatide. These are the active ingredients in Wegovy and Zepbound. It did not compare Ozempic with an unknown tirzepatide product. The 72-week study included adults with obesity, or overweight plus a related health problem. None had type 2 diabetes. The tirzepatide group lost a larger share of body weight on average.

The result is a group average, not a promise. People and researchers knew which medicine each person received, so the study was open label. The tirzepatide maker funded it. Each person used the highest study amount they could tolerate. The study did not rank every use or product.

FDA labels include benefits beyond weight. Wegovy injection has defined adult uses for weight, heart risk, and MASH, a serious fatty liver disease. Its MASH use has accelerated approval, so more proof is required. Zepbound treats moderate-to-severe obstructive sleep apnea in adults with obesity. This condition causes breathing to stop during sleep. Ozempic, Rybelsus, and Mounjaro have different diabetes-focused labels. Compare the exact product, people, result, risks, and access—not which molecule “wins.”

02

How the medicines act does not predict one person's result.

Both medicines affect blood sugar, appetite, food intake, and how fast the stomach empties. These effects cannot predict one person's weight change, heart result, or side effects.

A trial result belongs to its product, form, study plan, people, comparison, length, and measured result. Researchers call the measured result an endpoint. A heart benefit on one semaglutide label does not apply to every semaglutide product. A tirzepatide result in adults without diabetes cannot predict results in children, adults with diabetes, or unreviewed products.

Both labels warn that slower stomach emptying can affect medicines taken by mouth. Stomach and bowel side effects are common. Some medicine combinations can also raise the risk of low blood sugar. The tirzepatide label has a specific warning about birth-control pills when treatment starts and when the amount increases. A clinician and pharmacist must review these issues. Do not make these changes on your own.

03

The FDA has approved several different products.

One ingredient can appear in several approved products. Each comparison must name the product because approved uses, benefits, warnings, and coverage can differ.

• Wegovy injection contains semaglutide under FDA application 215256. Its label covers long-term weight reduction in defined adults and teens. It also covers lower heart risk in defined adults with heart disease and overweight or obesity. Under accelerated approval, it covers noncirrhotic MASH with F2–F3 liver scarring in defined adults.
• Wegovy tablets contain semaglutide under separate FDA application 218316. Their label covers long-term weight reduction and lower heart risk in defined adults. It does not cover teens or MASH. The tablets also have instructions for use by mouth.
• Wegovy HD is the 7.2 mg form within Wegovy injection's FDA application 215256. FDA approved it in March 2026 for long-term weight reduction in certain adults. SURMOUNT-5 did not study it.
• Ozempic injection contains semaglutide under FDA application 209637. Its label covers blood-sugar control and defined heart and kidney outcomes in adults with type 2 diabetes. SURMOUNT-5 did not use Ozempic as the semaglutide obesity product.
• Rybelsus and Ozempic tablets contain oral semaglutide under FDA application 213051. Their label covers blood-sugar control and lower risk of major heart events in defined adults with type 2 diabetes. The tablets are not equal milligram for milligram.
• Zepbound contains injectable tirzepatide under FDA application 217806. Its label covers long-term weight reduction in defined adults. It also covers moderate-to-severe obstructive sleep apnea in adults with obesity.
• Mounjaro contains injectable tirzepatide under FDA application 215866. Its January 2026 label covers blood-sugar control for people age 10 and older with type 2 diabetes. On August 27, 2026, FDA approved two changes. S-044 adds lower risk of cardiovascular death, nonfatal heart attack, and nonfatal stroke for high-risk adults with type 2 diabetes. Cardiovascular death means death from a heart or blood-vessel cause. S-045 allows 2.5 mg for ongoing blood-sugar control. The updated label is not posted. Zepbound's uses do not transfer.

04

What the direct obesity trial showed.

SURMOUNT-5 assigned 751 adults to groups by chance. They had obesity, or overweight plus a related health problem, without type 2 diabetes. Of these, 750 entered the main benefit and safety reviews. The study compared set plans for injectable tirzepatide and semaglutide for 72 weeks. Both groups also received lifestyle support. The main result was percentage weight change.

Researchers used a planned method called the modified treatment-regimen estimand. It sets the result and the rules used to compare groups. Mean weight change was −20.2% with tirzepatide and −13.7% with semaglutide. The estimated difference was −6.5 percentage points. The 95% confidence interval was −8.1 to −4.9. This is the study's uncertainty range. The method counted results after early stopping or use of another obesity medicine. It set separate rules for people who crossed to the other medicine or had surgery.

Average waist change also favored tirzepatide. Stomach and bowel problems were the most common events in both groups. They occurred mainly while the study amount increased. These are group averages from one study plan, not promises for one person.

The study was open label, so people and researchers knew which medicine each person received. Tirzepatide's maker, Eli Lilly, funded it and helped with the study and data. The study excluded type 2 diabetes. It did not compare heart events, death, sleep apnea, kidney disease, or liver results. It came before oral Wegovy and Wegovy HD. It supports a narrow conclusion about weight, not a winner for every person or result.

05

The diabetes head-to-head trial answered a different question.

SURPASS-2 compared tirzepatide with semaglutide in 1,879 adults with type 2 diabetes. Metformin alone had not controlled their blood sugar well enough. The 40-week, open-label study assigned people to groups by chance. It compared three set tirzepatide plans with one injectable semaglutide plan. The main result was glycated hemoglobin, or A1C, a measure of average blood sugar. It was not long-term weight control.

All three tirzepatide groups lowered A1C at least as much as, and more than, the semaglutide group. This met the study's rules for being no worse and for being better. The tirzepatide groups also had larger average weight reductions. Stomach and bowel side effects were common in both groups.

The result is not an ingredient ranking. In adults with type 2 diabetes taking metformin, tirzepatide produced larger average changes in A1C and weight during this 40-week study.

SURPASS-2 was open label and supported by Eli Lilly. The study devices and planned increases in the medicine amounts prevented full masking. Its 40-week length left only 16 weeks after medicine levels became steady in the highest tirzepatide group. It did not compare tirzepatide with Wegovy's current weight-loss injection plan, oral Wegovy, or Wegovy HD.

The study did not test Zepbound's sleep-apnea use. It also did not test Wegovy's heart or MASH uses. Together, SURPASS-2 and SURMOUNT-5 provide direct comparisons in two health settings. They still do not show that one ingredient is best for every result or person.

06

A benefit on one label does not apply to every product.

FDA approves exact products for exact uses. Wegovy injection's heart use applies to adults who have heart disease and overweight or obesity. Its MASH use covers defined adults with noncirrhotic F2–F3 liver disease. Noncirrhotic means that cirrhosis has not developed. This use has accelerated approval based on better liver tissue under a microscope. Proof of a clinical benefit is still required. These uses do not transfer to Ozempic, oral semaglutide, or a generic “semaglutide peptide.”

Zepbound's sleep-apnea use covers adults with obesity and moderate-to-severe obstructive sleep apnea. It does not cover every sleep problem. It also does not transfer to Mounjaro.

Ozempic injection covers blood-sugar control and defined heart and kidney outcomes in adults with type 2 diabetes. Rybelsus and Ozempic tablets cover blood-sugar and heart outcomes in defined adults with diabetes. These labels answer specific health questions. They do not name one online winner.

07

The major risks overlap, but the labels are different.

Wegovy and Zepbound have boxed warnings about thyroid C-cell tumors found in rodents. A boxed warning is FDA's strongest warning. It is not known whether this risk applies to people. Both labels say not to use the product with a personal or family history of medullary thyroid cancer. They give the same warning for Multiple Endocrine Neoplasia syndrome type 2, a rare inherited condition. Neither medicine has been shown to cause these tumors in people. The boxed warnings state that the human risk is unknown.

The two labels also share several warning groups. This does not mean that every person will have these problems. It also does not mean that both products have the same level of risk.

Both labels warn about stomach and bowel reactions, which can be severe. They also warn about sudden pancreas inflammation, gallbladder disease, and sudden kidney injury linked to fluid loss. Other warnings cover serious allergic reactions and low blood sugar with some medicine combinations. For people with type 2 diabetes, the labels discuss diabetic retinopathy, which is eye damage from diabetes. They also report pulmonary aspiration during deep sedation or general anesthesia. This means stomach contents entered the lungs.

Most common side effects involve the stomach or bowel. The exact side effects and how often they occurred depend on the product, people, form, and study.

Some warnings differ. Wegovy's label includes an increase in heart rate. Zepbound's label says slower stomach emptying can affect birth-control pills when treatment starts and when the amount increases. The labels also differ for pregnancy, breastfeeding, medicines taken by mouth, device use, and product forms.

In January 2026, FDA said its review found no increased risk of suicidal thoughts or actions. It asked makers to remove that warning from GLP-1 weight-management drug labels. Wegovy recorded the removal in January. Zepbound recorded it in February. Older comparisons can therefore be out of date. Check the current label.

Safety is not as simple as “same class, same risk” or “more weight loss, more danger.” Study rates can change with time on a medicine, planned increases, definitions, follow-up, and who could join. A clinician must review reasons not to use a product and other medicines. The review must also cover past reactions, diabetic eye disease, anesthesia plans, pregnancy, and stomach or bowel disease.

08

The product form can change the comparison.

Zepbound and Mounjaro are FDA-approved injections. Their product forms include pens and vials. Ozempic is also an injection, but its forms and device instructions differ from Wegovy's. Wegovy includes single-dose injections and a tablet for defined adult uses. Wegovy HD is another Wegovy injection form for certain adults. Rybelsus and Ozempic tablets are oral semaglutide products for diabetes. Their label instructions affect how the body absorbs them.

The choice is more complex than “pill versus shot.” Oral semaglutide labels have rules about timing, water, food, and other medicines. Injection labels have product-specific rules for handling and storage. People cannot convert between brands or forms by matching milligrams. The current oral diabetes label says Rybelsus and Ozempic tablets are not equal milligram for milligram.

This guide does not give instructions for starting, increasing, missing, switching, or injecting a medicine. These details differ by product and can change. Use the current FDA label and ask the pharmacist about the exact prescribed form. For a fair comparison, name the brand, approved use, route, and current label. A route is how a medicine enters the body.

09

Access and cost depend on the exact product.

There is no single “semaglutide cost” or “tirzepatide cost.” First name the exact product and what the price includes. An online price can be a maker's list price, a pharmacy cash price, or a short-term savings price. It can also be an insurance copay or a clinic package with services and a different product.

These prices are not equal. Coverage can depend on the exact FDA-approved brand and approved use. It can also depend on age, diagnosis, plan year, the plan's drug list, approval rules, and pharmacy network.

For a current comparison, first name the prescribed product and approved use. Then check the insurer or benefits manager, pharmacy, and the maker's official program rules. Ask what a clinic price includes. It can include the FDA-approved product, visits, lab work, supplies, and follow-up. Also ask whether the price can change during care. A low monthly price without a product name is not a complete comparison.

Do not place compounded semaglutide or tirzepatide in the same evidence group as Wegovy, Ozempic, Rybelsus, Zepbound, or Mounjaro. FDA does not review compounded drugs for safety, effectiveness, or quality before marketing. FDA has reported errors in the amount given, false labels, and health problems reported after use. It has also found semaglutide salt forms that differ from the active ingredient in approved drugs.

A compounder's use of the molecule name does not establish equivalence to the approved product studied in a trial.

The summary has limits. In two direct studies, the tirzepatide groups had larger average changes in weight and blood sugar than the semaglutide groups. These results apply to the products, study plans, and people in each study. Current labels also differ in approved results, warnings, ages, routes, and product rules.

Cost and access need a current check for the exact product. These facts do not select treatment for one person. A licensed clinician must review the person's goals, health conditions, reasons not to use a medicine, other medicines, preferences, and coverage.

• Confirm the exact FDA-approved brand and route, not only the ingredient name.
• Match the wanted result to an approved use or a clearly limited study result.
• Read the current boxed warning, reasons not to use the product, major warnings, and medicine interactions.
• Check whether the study group matches the person in question. Important details include diabetes, age, heart disease, sleep apnea, kidney disease, and MASH stage.
• Check current coverage and total cost with the health plan and pharmacy. A price in search results is not a promised benefit.