Semaglutide vs Tirzepatide: Results, Side Effects and Cost

The short answer

Tirzepatide led to more weight loss in the head-to-head SURMOUNT-5 trial: 20.2% on average at 72 weeks, against 13.7% for semaglutide.
Side effects are similar in kind: mostly nausea, diarrhea, vomiting and constipation, worst while the dose is going up.
Semaglutide comes in more forms, including a daily pill, and it is the cheaper starting point. Brand-name tirzepatide costs $299 to $449 a month self-pay.
There is no official dose conversion between the two. Switching means following the new medicine's own dosing schedule with your clinician.

How they work

Both medicines copy gut hormones that your body releases after eating. Semaglutide, sold as Wegovy® and Ozempic®, activates the GLP-1 receptor ¹. Tirzepatide, sold as Zepbound® and Mounjaro®, activates both the GLP-1 and the GIP receptors ². Both slow the stomach, so you feel full sooner and for longer, and both act on appetite signals in the brain.

Lilly's label notes that laboratory studies suggest the GIP action adds to appetite control, but that extra benefit has not been proven separately in people ². What has been measured is the overall result.

The evidence: how much weight people lost

Trial	Medicine and dose	Average weight loss	Placebo
STEP 1 ⁴	Semaglutide 2.4 mg weekly	14.9% at 68 weeks	2.4%
SURMOUNT-1 ⁵	Tirzepatide 5 / 10 / 15 mg weekly	15.0% / 19.5% / 20.9% at 72 weeks	3.1%
SURMOUNT-5 ⁶	Tirzepatide 10–15 mg vs semaglutide 1.7–2.4 mg	20.2% vs 13.7% at 72 weeks	No placebo
STEP UP ¹⁰	Semaglutide 7.2 mg weekly	About 18.7% (20.7% in those who kept taking it) at 72 weeks	Yes

Trials were run with diet and activity advice, in adults without type 2 diabetes. Results are averages; individual results vary a great deal.

SURMOUNT-5 is the most useful study for this question because it put the two medicines side by side in the same trial. Among 751 adults, tirzepatide produced about 6.5 percentage points more weight loss and a larger cut in waist size, 18.4 cm against 13.0 cm ⁶⁷. The trial was funded by Lilly, which makes tirzepatide, and was open-label, meaning participants knew which drug they were taking.

The gap may narrow with the new higher dose of Wegovy®. At 7.2 mg, approved in March 2026 for people who need more weight loss after at least four weeks on 2.4 mg, semaglutide produced results closer to tirzepatide's ¹⁰. The two have not been compared head to head at that dose.

A doctor who prescribes both compares themDr. Lee, obesity and telemedicine physician, May 2026. Head-to-head results, side effects and cost.

How Zepbound® compares to Wegovy®Dr. Christopher McGowan, gastroenterologist and obesity specialist. A concise clinical comparison.

Side effects compared

The side effects are the same kind for both, mostly in the stomach and gut, and both are most likely while the dose is being increased ¹².

Side effect	Wegovy® 2.4 mg	Zepbound® 5 / 10 / 15 mg
Nausea	44%	25% / 29% / 28%
Diarrhea	30%	19% / 21% / 23%
Vomiting	24%	8% / 11% / 13%
Constipation	24%	17% / 14% / 11%
Stopped because of side effects	6.8%	4.8% / 6.3% / 6.7%

From each drug's prescribing information ¹². The trials were separate and designed differently, so compare these figures loosely.

In the head-to-head trial, 5.6% of people on semaglutide stopped because of stomach side effects, against 2.7% on tirzepatide ⁷. Both labels carry the same serious warnings, including a boxed warning about thyroid C-cell tumours seen in rodents, and both should not be used by people with a personal or family history of medullary thyroid cancer or MEN 2. Our side effects guide covers what to expect and how to manage it.

Doses and how you take them

Semaglutide injection (Wegovy®): once a week, starting at 0.25 mg and rising every four weeks through 0.5, 1 and 1.7 mg to a usual dose of 2.4 mg, with 7.2 mg as an option later ¹.
Tirzepatide injection (Zepbound®): once a week, starting at 2.5 mg for four weeks, then 5 mg, rising by 2.5 mg at least four weeks apart to a usual dose of 5, 10 or 15 mg ².
Semaglutide pill (Wegovy® pill): once a day, rising every 30 days from 1.5 to 4, 9 and then 25 mg. Take it on an empty stomach with a little water and wait 30 minutes before eating or drinking ¹.

Tirzepatide's starting dose is only for getting used to the medicine; it is not meant to be a long-term dose ².

The pills: Wegovy® pill and Foundayo®

Two GLP-1 pills are now approved for weight loss, both taken once a day:

The Wegovy® pill is oral semaglutide, approved in December 2025. In its main trial, people lost 13.6% on average at 64 weeks, or 16.6% among those who kept taking it ⁸.
Foundayo® is orforglipron, a different kind of GLP-1 medicine from Lilly, approved in April 2026. It can be taken with or without food. At the highest trial dose, average weight loss was 11.2% at 72 weeks ⁹.

Neither pill is tirzepatide. There is no approved tirzepatide pill; compounded oral or dissolvable tirzepatide is sold by some programs, but it is not FDA-approved and has not been shown in trials to work like the injection.

Cost compared

Option	Starting dose	Usual dose
Wegovy® pill (semaglutide)	$149/mo	$299/mo
Wegovy® pen (semaglutide)	$199/mo for two fills	$349/mo
Zepbound® (tirzepatide)	$299/mo	$449/mo
Compounded semaglutide	About $99 to $299/mo, usually including the clinician
Compounded tirzepatide	About $149 to $349/mo, usually including the clinician

Brand-name self-pay prices from Lilly and Novo Nordisk, read October 19, 2026 ¹²¹³. Compounded medicines are not FDA-approved. Our cost guide has the full price list.

Tirzepatide costs more in every form. Whether the extra weight loss is worth the extra cost is a personal decision; for many people starting out, semaglutide is a reasonable first step, with tirzepatide an option if results plateau.

Which one should you choose?

Tirzepatide if you have a lot of weight to lose, you have plateaued on semaglutide, or you want the medicine with the larger average result and can afford it.
Semaglutide if you want the lower-cost starting point, you would prefer a pill, or you have heart disease (Wegovy® is also approved to cut the risk of heart attack and stroke in people with established heart disease) ¹.
Either, decided with a clinician who knows your health history. The medicine you tolerate and stay on is the one that works.

Our #1 pick, TotalRx, prescribes both as compounded weekly injections, from $129 a month for semaglutide and $174 for tirzepatide on a 12-month plan, and its clinicians can move you from one to the other.

Switching between them

There is no official way to convert a semaglutide dose into a tirzepatide dose, and conversion charts found online are not validated ¹¹. Clinical guidance is to follow the new medicine's own schedule, usually starting low, and never to take the two together. Our guide to switching covers this, and what to ask a new provider.

Questions and answers

Is tirzepatide better than semaglutide?

For weight loss on average, yes: in SURMOUNT-5, people on tirzepatide lost 20.2% of their body weight at 72 weeks against 13.7% on semaglutide. Individual results vary widely, and some people do better on semaglutide or tolerate it better.

What is the difference between semaglutide and tirzepatide?

Semaglutide acts on one hormone receptor, GLP-1. Tirzepatide acts on two, GLP-1 and GIP. Both slow stomach emptying and reduce appetite.

Are Ozempic and Wegovy the same drug?

Both are semaglutide, made by Novo Nordisk. Wegovy® is approved for weight management at doses up to 2.4 mg (and now 7.2 mg); Ozempic® is approved for type 2 diabetes and is prescribed off-label for weight loss.

Are Mounjaro and Zepbound the same drug?

Both are tirzepatide, made by Lilly. Zepbound® is approved for weight management and obstructive sleep apnea; Mounjaro® is approved for type 2 diabetes.

Which has fewer side effects?

In the trials, nausea was reported by about 44% on Wegovy® 2.4 mg and about 25 to 29% on Zepbound®, though the trials were run differently, so the figures are not a direct comparison. In SURMOUNT-5, more people stopped semaglutide because of stomach side effects (5.6%) than tirzepatide (2.7%).

Can I switch from semaglutide to tirzepatide?

Yes, with your clinician. There is no validated dose conversion, so you would usually start tirzepatide on its own schedule rather than at an 'equivalent' dose, and you should not take both together.

Is there a tirzepatide pill?

Not an approved one. The approved GLP-1 pills are the Wegovy® pill (semaglutide) and Foundayo® (orforglipron). Compounded oral or dissolvable tirzepatide products are sold by some programs, but they are not FDA-approved and have not been shown in trials to work like the injection.

Which is cheaper?

Self-pay, brand-name semaglutide starts lower: the Wegovy® pill is $149 to $299 a month and the Wegovy® pen $349 after two introductory fills, against $299 to $449 for Zepbound®. Compounded versions of both cost less.

Sources

How we write our guides. We read the manufacturers' prescribing information, FDA and other official sources, published trials and each provider's own pricing and policies, and link to them so you can check our work. Figures were correct when we last checked them on October 19, 2026; prices and rules change often, so confirm them before you act. Medical disclaimer. This guide is general information, not medical advice, and no one at ProviderCompare is your clinician. Talk to a licensed healthcare professional before starting, changing or stopping any medication. Compounded GLP-1 medications are not FDA-approved and do not undergo FDA review for safety, effectiveness or quality. Brand names are trademarks of their owners, used for identification only.

Semaglutide vs tirzepatide: which works better, and which is right for you