Tirzepatide (Zepbound, Mounjaro, Compounded): Evidence, Dosing, Side Effects and 2026 Telehealth Prices

What tirzepatide is

Tirzepatide is a once-weekly injectable peptide that activates two incretin receptors at once: the glucose-dependent insulinotropic polypeptide (GIP) receptor and the glucagon-like peptide-1 (GLP-1) receptor. It was developed by Eli Lilly and approved by the FDA as Mounjaro for type 2 diabetes in May 2022, as Zepbound for chronic weight management in November 2023, and for moderate-to-severe obstructive sleep apnea in adults with obesity in December 2024. It is the first dual-agonist in its class and, as of 2026, the most effective weight-loss medication approved in the United States.

The same molecule is also sold by telehealth companies as compounded tirzepatide, prepared by compounding pharmacies from bulk active pharmaceutical ingredient. Compounded tirzepatide is not FDA-approved. The sections below cover the molecule's evidence base, which applies to the approved products, and then explain what changes when the product is compounded.

How it works

GLP-1 and GIP are hormones released by the gut after eating. Both stimulate insulin secretion in a glucose-dependent way, which is why they lower blood sugar without causing hypoglycemia on their own. GLP-1 also suppresses glucagon, slows gastric emptying, and acts on appetite centers in the hypothalamus and brainstem to reduce hunger and increase satiety. GIP's contribution is less intuitive: on its own it is a weak weight-loss signal, but in combination it appears to amplify the GLP-1 effect on appetite and, in preclinical work, to act on adipose tissue and reduce the nausea that limits GLP-1 dosing. Tirzepatide is engineered with a higher affinity for the GIP receptor than for the GLP-1 receptor, a fatty-acid side chain that binds albumin, and a half-life of about five days, which permits once-weekly dosing.

The clinical result is a larger effect than any single-agonist GLP-1 medication has produced, at a tolerability similar to semaglutide.

The evidence: the SURMOUNT program

SURMOUNT-1 (NEJM, 2022) randomized 2,539 adults with obesity, or overweight plus a weight-related condition, without diabetes, to tirzepatide 5, 10 or 15 mg or placebo for 72 weeks alongside lifestyle counseling. Mean weight change was −15.0% on 5 mg, −19.5% on 10 mg, −20.9% on 15 mg and −3.1% on placebo. The share of participants losing at least 20% of body weight was 30% on 5 mg, 50% on 10 mg and 57% on 15 mg, versus 3% on placebo. A three-year extension published in 2024 reported a 94% reduction in progression to type 2 diabetes among participants with prediabetes.

SURMOUNT-2 (Lancet, 2023) enrolled 938 adults with obesity and type 2 diabetes. Weight loss was smaller, as it is with every agent in this population: −12.8% on 10 mg and −14.7% on 15 mg versus −3.2% on placebo at 72 weeks, with HbA1c reductions of about 2.1 percentage points.

SURMOUNT-3 (Nature Medicine, 2023) tested tirzepatide after a 12-week intensive lifestyle lead-in in which participants had already lost at least 5%. Over the following 72 weeks, tirzepatide produced an additional −18.4% versus +2.5% regain on placebo.

SURMOUNT-4 (JAMA, 2024) answered the discontinuation question directly. After 36 weeks of open-label tirzepatide (mean loss −20.9%), participants were randomized to continue or switch to placebo for 52 weeks. Continuers lost a further 5.5%; those switched to placebo regained 14.0% of body weight, recovering roughly two-thirds of what they had lost. Tirzepatide, like every obesity medication studied so far, treats obesity while it is taken and does not cure it.

SURMOUNT-5 (NEJM, 2025) is the trial patients ask about most: a head-to-head against semaglutide 2.4 mg in 751 adults with obesity without diabetes. At 72 weeks, mean weight change was −20.2% on tirzepatide versus −13.7% on semaglutide, a 47% relative advantage. Waist circumference fell 18.4 cm versus 13.0 cm. The proportion losing at least 25% was 31.6% versus 16.1%. Gastrointestinal adverse events were similar in frequency between arms.

SURMOUNT-OSA (NEJM, 2024) led to the sleep apnea indication: in adults with obesity and moderate-to-severe OSA, tirzepatide reduced the apnea-hypopnea index by 25 to 29 events per hour versus 5 to 6 on placebo, and about half of participants reached a level where CPAP was no longer indicated.

Cardiovascular outcome data (SURPASS-CVOT in type 2 diabetes, comparing tirzepatide with dulaglutide) reported non-inferiority for major adverse cardiovascular events in 2025; the SURMOUNT-MMO trial in obesity without diabetes is ongoing.

Dosing and titration

Per the Zepbound prescribing information, treatment starts at 2.5 mg once weekly for four weeks. The dose is then increased in 2.5 mg increments, each for at least four weeks, through 5, 7.5, 10 and 12.5 mg to a maximum of 15 mg. The recommended maintenance doses are 5, 10 or 15 mg; 7.5 and 12.5 mg are transitional. A patient following the label reaches 10 mg in month four and 15 mg in month six. If a dose increase is not tolerated, the label allows staying at the lower dose or delaying the next step.

This schedule matters for pricing. A provider that charges by dose tier will bill the starting price for one or two months and the top-tier price from roughly month four onward. Our 12-month cost model uses three months at the starting price, which is deliberately generous to dose-based providers. Telehealth prescribers sometimes escalate more slowly than the label to manage side effects, which extends the lower-priced months but also delays the full effect.

Side effects by dose

In SURMOUNT-1, the most common adverse events over 72 weeks were gastrointestinal and dose-related:

• Nausea: 24.6% (5 mg), 33.3% (10 mg), 31.0% (15 mg) versus 9.5% placebo
• Diarrhea: 18.7%, 21.2%, 23.0% versus 7.3%
• Vomiting: 8.3%, 10.7%, 12.2% versus 1.7%
• Constipation: 16.8%, 17.1%, 11.7% versus 5.8%
• Dyspepsia: 8.7%, 9.8%, 10.2% versus 4.4%

Most events were mild to moderate and clustered during dose escalation. Discontinuation because of adverse events was 4.3%, 7.1% and 6.2% versus 2.6% on placebo. Injection-site reactions, hair loss (about 5% versus 1%) and fatigue were also more common than placebo. Serious adverse events did not differ from placebo. The label carries the class boxed warning for thyroid C-cell tumors seen in rodents and warnings for pancreatitis, gallbladder disease, hypoglycemia with insulin or sulfonylureas, acute kidney injury from dehydration, hypersensitivity, severe gastrointestinal disease, and aspiration risk under anesthesia. See the important safety information.

Body composition

A DXA substudy of SURMOUNT-1 found that about 25% of the weight lost on tirzepatide was lean mass and 75% fat mass, a ratio similar to what diet-induced weight loss produces. The practical implication, supported by resistance-training literature rather than tirzepatide-specific trials, is that protein intake of 1.2 to 1.6 grams per kilogram per day and resistance exercise twice weekly reduce lean-mass loss. The protein and water tool computes targets.

Compounded tirzepatide: what changes

When the FDA listed tirzepatide as in shortage (December 2022), compounding pharmacies became legally able to prepare copies for patients who could not obtain the approved product. Telehealth companies built a large market on that basis, typically at a fraction of the brand price. On December 19, 2024, the FDA declared the shortage resolved and set deadlines — February 18, 2025 for 503A pharmacies and March 19, 2025 for 503B outsourcing facilities — after which compounding "essentially a copy" of Zepbound or Mounjaro is not permitted.

What remains legal is compounding for an individual patient when the prescriber documents a clinical need for a formulation the approved product does not provide: a different strength, an additive such as vitamin B12, or a different dosage form. This is the basis on which telehealth providers continue to offer compounded tirzepatide in 2026, including "microdose" protocols and sublingual or orally disintegrating tablets. The FDA has warned that it does not consider a formulation change made to evade the copy prohibition to be a legitimate clinical need, and Eli Lilly has sued several telehealth companies over marketing claims. Whether a given provider's protocol falls on the right side of that line is a legal question that no comparison site can answer; what a patient can verify is that the dispensing pharmacy is licensed in their state and, for 503B products, registered with the FDA.

Three clinical cautions are specific to compounded tirzepatide. First, the product arrives as a multi-dose vial, so the patient draws up each dose with a syringe; the FDA has reported overdoses from unit and milliliter confusion. Second, some compounders have used tirzepatide salt forms rather than the base peptide in the approved product. Third, there are no pharmacokinetic studies of sublingual or ODT tirzepatide; the molecule is a 39-amino-acid peptide with negligible oral bioavailability, and the approved oral GLP-1 (semaglutide as Rybelsus and oral Wegovy) required a proprietary absorption enhancer and a 25 mg dose to achieve about 1% bioavailability. A sublingual tirzepatide product may or may not deliver a meaningful dose; a patient choosing one should understand that the evidence base for injectable tirzepatide does not transfer.

Brand-name tirzepatide: prices and access

Zepbound is available in pens through pharmacies and, since 2024, in single-dose vials through Lilly's self-pay channel, LillyDirect, at prices that fell substantially in late 2025. Insurance coverage for obesity remains inconsistent; Medicare Part D does not cover medications for weight loss alone, though it covers Zepbound for OSA and Mounjaro for diabetes. Telehealth programs built around insurance, such as Ro, handle prior authorization. See the LillyDirect benchmark row in our database for the brand self-pay price and its verification status.

Who tirzepatide is for

The Zepbound label covers adults with a BMI of 30 or higher, or 27 or higher with at least one weight-related condition, as an adjunct to reduced-calorie diet and increased physical activity; and adults with obesity and moderate-to-severe OSA. It is contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2, and should not be used in pregnancy or with other GLP-1 receptor agonists. The eligibility screener applies the label criteria; a clinician makes the decision.

What it costs at each telehealth provider

The ranked list below is computed from our pricing database and ordered by 12-month all-in total. Providers offering tirzepatide whose prices we have not yet verified are listed after it.

Providers offering tirzepatide, ranked by 12-month all-in cost

Also offering tirzepatide, pricing pending verification: Henry Meds, Shed (ShedRx), WeightWatchers Clinic, Calibrate, Lavender Sky Health, LifeMD, Strut Health, Fridays, Ageless, Wellorithm, ReflexMD, IvyRx.