Semaglutide vs Tirzepatide: Weight Loss, Side Effects, Cost

Semaglutide and tirzepatide are the two active ingredients behind nearly every prescription in the current wave of diabetes and weight-loss medicines. Semaglutide is sold as Ozempic, Wegovy and Rybelsus. Tirzepatide is sold as Mounjaro and Zepbound. In the two randomized trials that compared them head to head, tirzepatide lowered blood sugar and body weight more: about 20% average weight loss versus about 14% in adults with obesity, and a larger drop in A1C in adults with type 2 diabetes. Semaglutide has the broader list of FDA-approved uses, including kidney disease and liver disease, and it is the only one of the two available as a pill.

This page compares the molecules. If you are choosing between two specific brands, the brand-by-brand comparisons are linked throughout. Nothing here replaces a conversation with your prescriber.

Semaglutide vs tirzepatide: the short version

	Semaglutide	Tirzepatide
Drug class	GLP-1 receptor agonist	GIP and GLP-1 receptor agonist
Brand names	Ozempic (injection and tablets), Wegovy (injection and tablets), Rybelsus (tablets)	Mounjaro, Zepbound (both injections)
Maker	Novo Nordisk	Eli Lilly
Forms	Weekly injection; daily tablet	Weekly injection only
Weekly injection dose range	0.25 mg to 2 mg (Ozempic); 0.25 mg to 2.4 mg, with a 7.2 mg option (Wegovy)	2.5 mg to 15 mg
Half-life	About 1 week	About 5 days
Average weight loss in its pivotal obesity trial	14.9% at 68 weeks (2.4 mg, STEP 1)	15.0% to 20.9% at 72 weeks (5 to 15 mg, SURMOUNT-1)
Head-to-head weight result (SURMOUNT-5)	13.7%	20.2%
FDA-approved uses across brands	Type 2 diabetes; cardiovascular risk reduction; chronic kidney disease in type 2 diabetes; weight management from age 12; MASH with liver fibrosis	Type 2 diabetes from age 10; cardiovascular risk reduction in type 2 diabetes; weight management in adults; obstructive sleep apnea in adults with obesity
Generic available in the U.S.?	No	No

What each drug is

Semaglutide is a modified copy of the human hormone GLP-1. Natural GLP-1 lasts only minutes in the bloodstream. Semaglutide is engineered to bind to albumin, a blood protein, which stretches its half-life to about a week and makes once-weekly dosing possible. It increases insulin release when blood sugar is high, lowers glucagon, slows stomach emptying and reduces appetite.

Tirzepatide is a single molecule that activates two receptors: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). Its half-life is about five days, which also supports weekly dosing. The FDA labels describe it as a "GIP receptor and GLP-1 receptor agonist," a class of its own.

So, is tirzepatide a GLP-1? Partly. It does everything a GLP-1 drug does and adds GIP activity. Is semaglutide the same as tirzepatide? No. They are different molecules made by different companies, measured on different dose scales, and they cannot be substituted for each other at the pharmacy.

The brands, sorted

Brand	Ingredient	Form	FDA-approved for
Ozempic	Semaglutide	Weekly injection; daily tablet (1.5, 4, 9 mg)	Type 2 diabetes; cardiovascular risk; kidney disease in type 2 diabetes (injection)
Rybelsus	Semaglutide	Daily tablet (3, 7, 14 mg)	Type 2 diabetes; cardiovascular risk in type 2 diabetes
Wegovy	Semaglutide	Weekly injection; daily tablet (up to 25 mg)	Weight management; cardiovascular risk in adults with obesity or overweight; MASH (injection)
Mounjaro	Tirzepatide	Weekly injection	Type 2 diabetes from age 10; cardiovascular risk in type 2 diabetes
Zepbound	Tirzepatide	Weekly injection	Weight management in adults; moderate to severe obstructive sleep apnea with obesity

The brand-level comparisons: Ozempic vs Mounjaro for type 2 diabetes, Wegovy vs Zepbound for weight management, Ozempic vs Wegovy for the two semaglutide injections, and Mounjaro vs Zepbound for the two tirzepatide injections.

Tirzepatide vs semaglutide for weight loss

Three kinds of evidence line up.

The head-to-head trial

SURMOUNT-5, published in the New England Journal of Medicine in 2025, randomly assigned 751 adults with obesity and without diabetes to the highest dose they could tolerate of tirzepatide (10 mg or 15 mg) or semaglutide (1.7 mg or 2.4 mg) for 72 weeks. Average weight loss was 20.2% with tirzepatide and 13.7% with semaglutide. In pounds, that was about 50 versus 33. Waist circumference fell by 18.4 cm versus 13.0 cm. About 32% of the tirzepatide group lost at least a quarter of their body weight, compared with 16% of the semaglutide group. Eli Lilly, tirzepatide's maker, funded the trial; participants knew which drug they were getting.

The placebo-controlled trials

Trial	Drug and dose	Length	Average weight change	Placebo
STEP 1	Semaglutide 2.4 mg	68 weeks	-14.9%	-2.4%
STEP UP	Semaglutide 7.2 mg	72 weeks	-18.7%	-3.9%
SURMOUNT-1	Tirzepatide 5 mg	72 weeks	-15.0%	-3.1%
SURMOUNT-1	Tirzepatide 10 mg	72 weeks	-19.5%	-3.1%
SURMOUNT-1	Tirzepatide 15 mg	72 weeks	-20.9%	-3.1%

These trials enrolled different people at different times, so the rows are not a direct contest. They do show that the newer 7.2 mg semaglutide dose, approved in March 2026 as Wegovy HD, closes much of the distance to tirzepatide. No trial has yet compared semaglutide 7.2 mg with tirzepatide directly.

Real-world records

A 2024 study in JAMA Internal Medicine matched 18,386 U.S. adults with overweight or obesity who started one drug or the other, mostly the diabetes-labeled versions. People on tirzepatide lost more weight at 3, 6 and 12 months; at one year the difference was 6.9 percentage points. More than half of patients in both groups stopped treatment during follow-up, a reminder that results in clinics depend heavily on whether people can stay on the drug and afford it.

In people who have type 2 diabetes, both drugs produce less weight loss than in people who do not. In the labels, semaglutide 2.4 mg produced 9.6% average weight loss in adults with diabetes, and tirzepatide 10 mg and 15 mg produced 12.8% and 14.7%.

For type 2 diabetes

SURPASS-2 compared tirzepatide 5, 10 and 15 mg with semaglutide 1 mg in 1,879 adults with type 2 diabetes on metformin. After 40 weeks, A1C fell by 2.0, 2.2 and 2.3 points on tirzepatide and 1.9 points on semaglutide, from a starting point of 8.3%. Weight fell by 7.6, 9.3 and 11.2 kg on tirzepatide and 5.7 kg on semaglutide. The 10 mg and 15 mg results were statistically superior. Semaglutide's 2 mg dose, which did not exist when that trial was designed, adds roughly 0.2 to 0.3 points of A1C reduction over 1 mg, according to the SUSTAIN FORTE trial.

Benefits beyond the scale and the glucose meter

This is where semaglutide's longer time on the market shows.

Outcome	Semaglutide	Tirzepatide
Heart attack, stroke, cardiovascular death	Reduced by 26% versus placebo in type 2 diabetes (SUSTAIN-6) and by 20% versus placebo in adults with obesity and heart disease but no diabetes (SELECT, 17,604 people). FDA-approved indications under Ozempic, Rybelsus and Wegovy.	Non-inferior to dulaglutide in type 2 diabetes with cardiovascular disease (SURPASS-CVOT, hazard ratio 0.92; superiority not shown). FDA-approved indication under Mounjaro since August 2026.
Kidney disease	24% lower risk of major kidney outcomes in type 2 diabetes with chronic kidney disease (FLOW). FDA-approved under Ozempic.	No kidney indication.
Liver disease (MASH)	FDA accelerated approval under Wegovy for MASH with moderate to advanced fibrosis.	No liver indication.
Obstructive sleep apnea	No sleep apnea indication.	FDA-approved under Zepbound; in SURMOUNT-OSA, breathing interruptions fell by 25 to 29 events per hour versus about 5 with placebo.

Searches for "semaglutide vs tirzepatide for inflammation" have grown, largely because both drugs lower blood markers such as C-reactive protein in trials. That is a laboratory finding. Neither drug is approved to treat an inflammatory condition, and a marker moving is not the same as a disease improving.

Tirzepatide vs semaglutide side effects

The two share a profile: nausea, diarrhea, vomiting, constipation and abdominal pain, mostly during dose increases. The percentages below come from the weight-management labels, where doses are highest and side effects are most common.

Side effect	Semaglutide 2.4 mg (Wegovy)	Tirzepatide 5 / 10 / 15 mg (Zepbound)
Nausea	44%	25% / 29% / 28%
Diarrhea	30%	19% / 21% / 23%
Vomiting	24%	8% / 11% / 13%
Constipation	24%	17% / 14% / 11%
Abdominal pain	20%	9% / 9% / 10%
Fatigue	11%	5% / 6% / 7%
Hair loss	3%	5% / 4% / 5%
Injection-site reactions	not in the common list	6% / 8% / 8%

Because these numbers come from separate trials with separate placebo groups, they cannot prove one drug is gentler. In SURMOUNT-5, where the drugs were compared directly, gastrointestinal effects were the most common problem in both arms and most were mild to moderate.

Hair loss. Hair shedding shows up in both labels at low rates and is thought to be tied to rapid weight loss rather than to the drug itself. With semaglutide 7.2 mg the rate rose to 6%. It is usually temporary; mention it to your clinician if it persists, since low protein or iron intake can contribute.

Skin sensitivity. A tingling, burning or sensitive-skin sensation called dysesthesia was reported in 22% of people on semaglutide 7.2 mg in the label, compared with 6% on 2.4 mg.

Serious risks, both drugs: a boxed warning for thyroid C-cell tumors seen in rodents; pancreatitis; gallbladder disease; low blood sugar with insulin or sulfonylureas; kidney injury from dehydration; severe gastrointestinal reactions; allergic reactions; worsening diabetic retinopathy in people with type 2 diabetes; and aspiration risk under anesthesia. Neither should be used by anyone with a personal or family history of medullary thyroid carcinoma or with MEN 2. Seek emergency care for severe abdominal pain that does not ease, or for swelling of the face or throat or trouble breathing.

Birth control pills. Tirzepatide labels advise using a non-oral or backup barrier method for four weeks after starting and after each dose increase. Injectable semaglutide labels carry no such instruction.

Dosing: why the milligrams look so different

People often ask whether tirzepatide is "stronger" because its doses run up to 15 mg while semaglutide tops out at 2 or 2.4 mg for most patients. The numbers cannot be compared that way. Each molecule has its own potency per milligram; 5 mg of tirzepatide is not "double" 2.4 mg of semaglutide in any meaningful sense. What can be compared is the outcome at approved doses, and there tirzepatide has produced larger average reductions in weight and A1C.

Step	Semaglutide injection for weight (Wegovy)	Tirzepatide injection (Zepbound or Mounjaro)
Weeks 1 to 4	0.25 mg	2.5 mg
Weeks 5 to 8	0.5 mg	5 mg
Weeks 9 to 12	1 mg	5 mg, or 7.5 mg if increasing
Weeks 13 to 16	1.7 mg	Up to 10 mg
Week 17 on	2.4 mg (or stay at 1.7 mg); 7.2 mg is an option after at least 4 weeks on 2.4 mg	Up to 12.5 mg, then 15 mg

Tirzepatide moves in 2.5 mg steps, each held for at least four weeks. There is no FDA-endorsed conversion chart between the drugs; what clinicians actually do is covered in switching from semaglutide to tirzepatide.

Pills: only semaglutide, so far

Semaglutide comes as a daily tablet in three brands: Rybelsus and Ozempic tablets for type 2 diabetes and Wegovy tablets (25 mg maintenance dose) for weight management. The tablets must be taken on an empty stomach with no more than 4 ounces of water, 30 minutes before food, drink or other medicines. Tirzepatide has no oral form. Eli Lilly's pill is a different molecule, orforglipron, approved in April 2026 as Foundayo. See Foundayo vs the Wegovy pill.

Cost as of October 2026

Manufacturer self-pay prices, checked October 14, 2026:

Product	Self-pay price per month
Wegovy injection (semaglutide)	$199 for the first two fills of 0.25 or 0.5 mg (new patients, through December 31, 2026), then $349; $399 for 7.2 mg
Ozempic injection (semaglutide)	$199 for the first two starter fills (new patients), then $349; $499 for 2 mg
Wegovy tablets (semaglutide)	$149 (1.5 mg), $199 (4 mg), $299 (9 and 25 mg)
Zepbound vial or KwikPen (tirzepatide)	$299 (2.5 mg), $399 (5 mg), $449 for 7.5 to 15 mg when refilled within 45 days; otherwise $499 (7.5 mg) and $699 (10 to 15 mg)
Mounjaro pens (tirzepatide)	From $499

At maintenance doses, brand-name semaglutide is now roughly $100 a month cheaper than brand-name tirzepatide for cash payers. Details and insurance scenarios are in GLP-1 cost without insurance.

Compounded semaglutide and tirzepatide

Many searches for this comparison come from telehealth ads for compounded versions. Here is where things stand.

• Compounded drugs are not FDA-approved. The agency does not review them for safety, effectiveness or quality before they are sold.
• Large-scale compounding was permitted while the brand-name injections were on the FDA's shortage list. The FDA declared the tirzepatide shortage resolved in late 2024 and the semaglutide shortage resolved on February 21, 2025, and the grace periods for compounders ended in 2025.
• On February 6, 2026, the FDA announced it intends to restrict GLP-1 ingredients used in mass-marketed compounded products. On April 30, 2026, it proposed excluding semaglutide, tirzepatide and liraglutide from the list of bulk substances that outsourcing facilities may compound.
• There is no FDA-approved generic semaglutide or tirzepatide in the United States.

With manufacturer cash prices now starting at $149 to $299 a month, the price argument for compounded products is weaker than it was. If you use one, ask the pharmacy what form of the ingredient it uses, how the dose is measured, and whether a licensed prescriber is reviewing your care. The same caution applies to non-prescription products that borrow the GLP-1 name, such as the GLP-1 patches sold online.

Semaglutide or tirzepatide: questions to bring to your appointment

1. What am I treating: type 2 diabetes, weight, sleep apnea, heart or kidney risk, liver disease? The approved uses differ.
2. Which one does my insurance cover, and at what tier? Formularies often prefer one.
3. Do I have a history of pancreatitis, gallbladder disease, thyroid cancer in the family or diabetic eye disease?
4. Am I on birth control pills, insulin or a sulfonylurea?
5. Would I rather take a daily pill with fasting rules or a weekly injection?
6. If I pay cash, what will the maintenance dose cost me per year, not just the starter dose?
7. What is the plan if I plateau, cannot tolerate a dose, or need to stop?

Both drugs are long-term treatments. In the STEP 1 extension, people regained about two-thirds of lost weight within a year of stopping semaglutide, and SURMOUNT-4 showed substantial regain after tirzepatide was withdrawn. Choosing the drug you can stay on, medically and financially, matters as much as choosing the one with the biggest trial number.