Tirzepatide: the dual-hormone drug behind Mounjaro and Zepbound
How this page is paid for: Some links here are partner links. If you start care through one, the provider may pay LongevityGLP1 a fee, and your monthly price stays the same. How we make money
The short answer
Tirzepatide is a weekly injection that acts on two hormone receptors, GIP and GLP-1, to lower blood sugar and appetite. Eli Lilly sells it as Mounjaro for type 2 diabetes and as Zepbound for weight management and obstructive sleep apnea. In its main obesity trial, people on the top dose lost 20.9% of body weight in 72 weeks.
Definition
Tirzepatide is a once-weekly injectable that activates two gut-hormone receptors, GIP and GLP-1. Eli Lilly sells it as Mounjaro (type 2 diabetes, approved May 13, 2022) and Zepbound (weight management, approved November 8, 2023; sleep apnea, December 20, 2024).
Key facts
| Fact | Detail |
|---|---|
| Drug class | Dual GIP and GLP-1 receptor agonist |
| Maker | Eli Lilly |
| Brands | Mounjaro (type 2 diabetes); Zepbound (weight, sleep apnea) |
| Form | Weekly injection: single-dose pen, single-dose vial, multi-dose vial, KwikPen[1] |
| Tablet | None approved |
| Compounded | Not FDA-approved; shortage declared over December 19, 2024[8] |
| Brand self-pay | Zepbound from $299 a month; Mounjaro from $499 (LillyDirect) |
| Compounded, online | $85–$433 a month |
| Prescription | Required |
In its main obesity trial, tirzepatide cut body weight by about 21% on the top dose, and head to head it beat semaglutide. It's also a little confusing, because it goes by two names. Mounjaro and Zepbound are the same molecule, from the same company, in the same pens and vials. What differs is the label, and the label decides who it's approved for and what it costs.
Tirzepatide acts on two hormone receptors, not one
Tirzepatide activates both the GIP and GLP-1 receptors, the targets of two hormones your gut releases after you eat. The label says it “selectively binds to and activates both the GIP and GLP-1 receptors,” and a fatty-acid chain lets it bind to albumin in the blood, which is why one dose lasts a week [1].
- Insulin when blood sugar is high. It boosts insulin release in a glucose-dependent way and lowers glucagon [2].
- Better insulin sensitivity. In a clamp study after 28 weeks, tirzepatide made the body respond better to insulin.
- Slower stomach emptying. The delay is largest after the first dose and fades over time.
- Less appetite. GLP-1 is a regulator of appetite, and nonclinical studies suggest GIP adds to that effect [1].
Is tirzepatide a GLP-1? Partly. It's a GLP-1 receptor agonist and a GIP receptor agonist in one molecule. That second action is what sets it apart from semaglutide, which acts on GLP-1 alone.
Mounjaro and Zepbound are the same drug with different labels
Mounjaro and Zepbound both contain tirzepatide, made by Eli Lilly, in the same strengths and the same four presentations. Mounjaro is labeled for type 2 diabetes. Zepbound is labeled for weight and sleep apnea. Is tirzepatide the same as Zepbound, or as Mounjaro? It's the ingredient in both.
| Mounjaro | Zepbound | |
|---|---|---|
| Approved for | Blood sugar in type 2 diabetes (adults and children 10+); fewer heart events in high-risk adults with type 2 diabetes | Weight reduction and maintenance; moderate to severe sleep apnea with obesity |
| First approved | May 13, 2022 [4] | November 8, 2023 [6] |
| Later approvals | Children 10+ on December 19, 2025; heart-risk reduction on August 27, 2026 [5] | Sleep apnea on December 20, 2024 [7] |
| Forms | Single-dose pen, single-dose vial, multi-dose vial, KwikPen [2] | Same four [1] |
| Label maximum | 15 mg a week in adults; 10 mg in children | 15 mg a week |
| Self-pay (LillyDirect) | “Starting at $499/month,” every strength [11] | $299 to $449 a month, vial or KwikPen [10] |
| Insurance usually based on | A type 2 diabetes diagnosis | Obesity coverage, which varies by plan |
Labels from DailyMed (both effective August 2026); prices from LillyDirect.
What is tirzepatide's brand name? It has two, and you now know which is which. Our Zepbound vs Mounjaro comparison goes through coverage, price and the off-label question in more detail.
Tirzepatide is approved for diabetes, heart risk in diabetes, weight and sleep apnea
Across its two brands, tirzepatide is approved for four uses. Mounjaro covers blood sugar control in type 2 diabetes for adults and children 10 and older, and lowering the risk of heart attack, stroke and cardiovascular death in adults with type 2 diabetes at high risk [2]. Zepbound covers weight reduction and maintenance in adults with obesity or overweight plus a related condition, and moderate to severe sleep apnea in adults with obesity [1].
The heart-risk approval rests on SURPASS-CVOT, which tested tirzepatide against dulaglutide, an older GLP-1 drug already shown to lower heart events, in 13,165 adults with type 2 diabetes and heart disease. Heart events occurred in 12.2% on tirzepatide vs 13.1% on dulaglutide, which met the test for being no worse but not the test for being better [17]. The same data were added to Zepbound's label in August 2026 as information, not a new use.
The trials showed 15% to 21% weight loss and a head-to-head win over semaglutide
In SURMOUNT-1, adults with obesity and no diabetes lost 15.0%, 19.5% and 20.9% of their weight on 5, 10 and 15 mg over 72 weeks, against 3.1% on placebo [12]. About half of people on 10 or 15 mg lost at least 20%.
| Trial | Who was studied | Result | Funded by |
|---|---|---|---|
| SURMOUNT-1 [12] | 2,539 adults with obesity, no diabetes, 72 weeks | Weight −15.0% to −20.9% vs −3.1% | Eli Lilly |
| SURMOUNT-5 [13] | 751 adults with obesity, no diabetes, 72 weeks, open-label | Weight −20.2% vs −13.7% on semaglutide | Eli Lilly |
| SURMOUNT-4 [14] | 670 adults after a 36-week lead-in on tirzepatide | Weeks 36 to 88: −5.5% if continued, +14.0% on placebo | Eli Lilly (Lilly-employed authors) |
| SURMOUNT-OSA [15] | Adults with moderate to severe sleep apnea and obesity, 52 weeks | Breathing events −25.3 vs −5.3 an hour (no CPAP) | Eli Lilly |
| SURPASS-2 [16] | 1,879 adults with type 2 diabetes on metformin, 40 weeks | A1C −2.01 to −2.30 points vs −1.86 on semaglutide 1 mg | Eli Lilly |
| SURPASS-CVOT [17] | 13,165 adults with type 2 diabetes and heart disease | Heart events 12.2% vs 13.1% on dulaglutide (hazard ratio 0.92) | Eli Lilly |
Nearly all tirzepatide evidence comes from trials Eli Lilly funded. That doesn't make the results wrong, but it's worth knowing.
The catch is in SURMOUNT-4. Everyone took tirzepatide for 36 weeks first and lost about 21% on average. Then half were switched to placebo. Over the next year, the placebo group regained 14.0% of their body weight, while the group that stayed on tirzepatide lost another 5.5% [14]. Like semaglutide, tirzepatide works while you take it.
Sleep apnea is the newest proof point. In SURMOUNT-OSA, breathing interruptions fell by 25.3 events an hour on tirzepatide vs 5.3 on placebo in people not using CPAP, and by 29.3 vs 5.5 in people who were [15]. That's what FDA based Zepbound's sleep apnea approval on.
Tirzepatide causes weight loss by cutting appetite and calorie intake
Tirzepatide leads to weight loss because people eat less. The Zepbound label says it “decreases calorie intake,” that “the effects are likely mediated by affecting appetite,” and that it “lowers body weight with greater fat mass loss than lean mass loss” [1]. Both GIP and GLP-1 receptors sit in brain areas that control appetite, and in animal studies tirzepatide reached and activated those areas.
Does tirzepatide burn fat? The label doesn't describe a fat-burning action. Fat comes off because calorie intake falls, with some lean mass lost too, as in any large weight loss. Why does it beat semaglutide on average? The likeliest reason is the added GIP action, but the label says only that nonclinical studies “suggest” GIP contributes. The head-to-head result is the hard evidence; the mechanism is still being worked out.
How does Mounjaro work for weight loss, then? The same way. Mounjaro's label notes that tirzepatide “decreases food intake, and reduces body weight” in people with type 2 diabetes [2], even though weight isn't its approved use.
Who tirzepatide is for, and who the label rules out
For weight, the Zepbound trials enrolled adults with a BMI of 30 or more, or 27 or more with a weight-related condition such as high blood pressure, abnormal cholesterol, sleep apnea or heart disease [1]. For diabetes, Mounjaro is for adults and children 10 and older with type 2 diabetes.
Both labels rule tirzepatide out for anyone with a personal or family history of medullary thyroid carcinoma or MEN 2, and for anyone who has had a serious allergic reaction to it. The Zepbound label says it may cause fetal harm, and both labels advise switching from birth-control pills to another method, or adding a barrier method, for four weeks after starting and after each dose increase. Your prescriber will also ask about pancreatitis, gallbladder problems and severe gastroparesis before writing it.
What the trials haven't answered yet
Some questions matter more to a longevity reader than to a diabetes clinic, and the trials don't settle them. No outcome trial shows tirzepatide extends lifespan. The heart-risk approval covers only adults with type 2 diabetes at high risk, and it rests on a comparison with another GLP-1 drug, not placebo [17].
Lean mass is the other open question. The label says more fat than lean mass is lost, but it doesn't say how much lean mass older adults can afford to lose, or what happens to muscle over years of treatment. If you're over 60, ask your prescriber how they'll protect strength, with protein and resistance training, while you're on it.
Most side effects are stomach-related and happen while the dose rises
Tirzepatide's most common side effects are nausea, diarrhea, vomiting, constipation and other stomach complaints, mostly during the first months while the dose is increased. In SURMOUNT-1, side effects led 4.3% to 7.1% of people to stop, against 2.6% on placebo [12]. Both brands carry a boxed warning about thyroid C-cell tumors seen in rodents.
| Side effect | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Nausea | 8% | 25% | 29% | 28% |
| Diarrhea | 8% | 19% | 21% | 23% |
| Vomiting | 2% | 8% | 11% | 13% |
| Constipation | 5% | 17% | 14% | 11% |
From the Zepbound label. Mounjaro's diabetes trials showed lower rates; nausea ran 12% to 18% vs 4% on placebo.
The labels also warn about severe stomach reactions, kidney injury from dehydration, gallbladder disease, pancreatitis, allergic reactions, low blood sugar with insulin or sulfonylureas, diabetic eye complications and aspiration during anesthesia. The full list, by brand and dose, is in our tirzepatide side effects guide.
There is no approved tirzepatide pill
No tirzepatide tablet is approved. Some online sellers offer compounded oral tirzepatide drops or tablets, but those are unapproved products with no published trial behind them. Lilly's GLP-1 pill, Foundayo, contains a different drug, orforglipron, which acts on GLP-1 receptors only and is taken daily [3].
Is orforglipron the same as tirzepatide? No. Different molecule, different receptors, different form. They share a maker and a goal, and that's it.
Compounded tirzepatide isn't FDA-approved and is legal only in narrow cases
Compounded tirzepatide is a pharmacy-made version. It isn't FDA-approved, FDA doesn't review it for safety or effectiveness, and FDA doesn't check its quality before it ships [9]. FDA declared the shortage resolved on December 19, 2024, and the grace periods for compounders ended in March 2025 [8]. FDA has received more than 730 reports of adverse events tied to compounded tirzepatide as of May 31, 2026 [9].
Telehealth programs still offer it under the remaining patient-specific rules. Our guides explain whether compounded tirzepatide is still available, whether it works, whether it's safe and how it compares with Zepbound. The basics are on the compounded tirzepatide page.
Tirzepatide beat semaglutide head to head; retatrutide is still in trials
Against semaglutide, tirzepatide produced more weight loss in SURMOUNT-5 and a larger A1C drop in SURPASS-2, in trials funded by Lilly [13] [16]. Our semaglutide vs tirzepatide comparison walks through both.
Retatrutide, Lilly's next drug, adds a third receptor, glucagon. It isn't FDA-approved for any use and can't legally be compounded. Read where retatrutide stands with FDA and the investigational comparison in retatrutide vs tirzepatide.
Brand tirzepatide costs $299 to $699 a month from LillyDirect
Zepbound costs $299 a month at 2.5 mg, $399 at 5 mg and $449 at higher doses through LillyDirect if you refill within 45 days, or $499 to $699 if you don't [10]. Mounjaro is listed “starting at $499/month” for every strength [11]. Same drug, different price, because the label differs.
| Brand and dose | Refill within 45 days | Otherwise |
|---|---|---|
| Zepbound 2.5 mg | $299 a month | $299 a month |
| Zepbound 5 mg | $399 a month | $399 a month |
| Zepbound 7.5 mg | $449 a month | $499 a month |
| Zepbound 10 to 15 mg | $449 a month | $699 a month |
| Mounjaro, any strength | Starting at $499 a month; Lilly says terms apply | Same |
Zepbound prices are for the vial or KwikPen, which need needles or pen needles bought separately.
Compounded tirzepatide from online programs runs $85–$433 a month across 69 programs. A sample, with whether each names its pharmacy:
| Provider | Plan | Monthly cost | Names its pharmacy |
|---|---|---|---|
| EdenPartner | Monthly | $129/mo | Yes |
| EmbodyPartner | 4-week plan | $140/mo | Yes |
| LTTLPartner | Monthly auto-refill or prepay | $161.42/mo | Yes |
| CoreAge RxPartner | 1-month plan; longer packages offered | $199/mo | No |
| Strut HealthPartner | Monthly auto-refill | $219/mo | No |
| GalaPartner | Monthly; 3-month plan offered | $299/mo | No |
Prices from each provider's own site and shown as a calendar-month cost at the starting plan, with required fees folded in.
For the details, read what compounded tirzepatide costs, or compare every program on the compounded tirzepatide board. If a program pitches very small doses, our guide to microdosing tirzepatide explains what hasn't been tested.
Every form of tirzepatide needs a prescription
Brand or compounded, tirzepatide needs a prescription. Your own clinician can send a Zepbound or Mounjaro prescription to LillyDirect Pharmacy or a local pharmacy. Telehealth programs prescribe both brand and compounded versions after an online intake and a clinician review.
Research on Tirzepatide
GLP-1 drugs, depression and anxiety: what FDA's latest review found
From their first approvals, Wegovy and Zepbound carried a warning about suicidal thoughts. In January 2026, after its largest review yet, FDA asked for it to come off. Here is what the agency studied, what the labels say now, and when a mood change still needs a call.
Alcohol on a GLP-1: what the labels say, and what they don't
None of the GLP-1 labels tells you whether you can drink. Several of their warnings still overlap with alcohol, and metformin's label is far more direct. Here's what each one says.
GLP-1 drugs and pregnancy: what the Ozempic, Wegovy and Zepbound labels say
The weight-loss GLP-1s are not for pregnancy, and the labels add rules for the months before it and for birth-control pills. Here is what each label says, so you can take the right questions to your prescriber.
GLP-1 drugs and muscle: how much of the weight lost is lean mass
Every way of losing weight takes some lean tissue with the fat. The question for a GLP-1 is whether it takes more than usual. Here's what the body scans showed, and what they can't tell you yet.
GLP-1 drugs and blood pressure: the drop in trials, and the low-pressure risk
Blood pressure fell in the big Zepbound and Wegovy weight trials. But neither drug is approved for it, and both labels report the opposite problem too. Here are the numbers.
Hair loss on Ozempic, Wegovy, Zepbound and Mounjaro: what the labels report
Hair loss is a listed side effect of the two GLP-1 weight drugs, and both labels tie it to weight loss. Here are the rates by drug and dose, why women see it more, and what the diabetes labels say.
How long Zepbound takes to work, from the first month to week 72
Zepbound starts working in the first weeks, but the big numbers people quote took a year and a half to reach. Here's the timeline from the trial behind its label, and what it means for your own first months.
What happens when you stop Ozempic, Wegovy or Zepbound
Three large trials stopped the drug on purpose to see what would happen. The answer was consistent: weight came back, and some health gains faded with it. Here's what each found, in numbers.
Compounded tirzepatide cost: what programs charge, month by month
The ongoing monthly price at each online program, with memberships folded in and four-week billing turned into calendar months.
How long compounded tirzepatide can stay out of the fridge
Compounded tirzepatide has no FDA storage label of its own. Here's what governs it, and the two FDA-backed figures worth knowing.
The starting dose of compounded tirzepatide, and why it isn't on a label
Compounded tirzepatide has no FDA label of its own. Here is the label prescribers borrow from, and the questions that keep a first dose safe.
Does compounded tirzepatide work? The evidence is all from Zepbound
The molecule has some of the strongest weight-loss data in medicine. The compounded products sold online have almost none of their own. Here’s how to read that gap, and what to check before you count on trial-like results.
GLP-1 telehealth explained: routes, checks and FDA's red flags
The three ways to get a GLP-1 online, what a real medical evaluation asks, who fills the prescription, and the warning signs FDA tells you to look for.
How safe is compounded tirzepatide? Label risks plus compounding risks
Every risk on the Zepbound label applies to compounded tirzepatide too. On top of those come the risks of a product nobody checks before it ships. Here’s each one, with what you can do about it.
Can you still get compounded tirzepatide? Where the rules stand
The shortage that made compounded tirzepatide everywhere ended in December 2024. Here's what's still allowed, what changed in 2025, what FDA proposed in 2026, and how to check a program is on the right side of the rules.
How safe is Mounjaro? The label, the heart trial and who should avoid it
What the US label says about Mounjaro's common side effects and serious risks, what the heart-outcomes trial found, and the birth-control point many people miss.
Microdosing tirzepatide: the idea, the evidence gap and the risks
Online programs sell "microdose" tirzepatide for smaller goals, fewer side effects or a lower bill. Here's what the label and trials actually cover, where the risks sit, and what to ask before you start.
Microdosing GLP-1 drugs: the claims, the evidence and the risks
Low-dose GLP-1 programs are sold for longevity, wellness and maintenance. Here is what the labels, the trials and the first real-world data actually show.
Tirzepatide side effects: what the Zepbound and Mounjaro labels report
One molecule, two labels. The side effects of tirzepatide by dose on Zepbound and Mounjaro, the warnings they share, and what's different about compounded versions.
How to get compounded tirzepatide the legal way
Four real routes, what each one costs right now, and the six things a legitimate program shows you before it takes your card.
Tirzepatide compared
Compounded tirzepatide vs Zepbound: what's the same and what isn't
Both contain tirzepatide. Only one has an FDA approval, a tested device and trial results behind it. Here is the comparison, row by row, with current prices.
Retatrutide vs tirzepatide: what the trials show, and what's approved
Retatrutide's phase 3 numbers are the largest yet for a weight drug, but they come from a different trial than tirzepatide's. Here's what can and can't be compared, and where each drug stands with FDA right now.
Semaglutide vs tirzepatide: what the head-to-head trials found
One drug acts on one gut-hormone receptor, the other on two. Here's what that difference did in the trials that tested them directly.
Wegovy or Mounjaro: start with which label fits you
Two different molecules from two different companies, approved for different people. Find your situation in the table and you'll know which label applies, and which drug is the fair comparison.
Compare providers
Compounded tirzepatide providers, scored
88 programs on this list
Tirzepatide programs that also treat menopause, scored
17 programs on this list
Tirzepatide programs that also treat low testosterone, scored
34 programs on this list
Compounded tirzepatide under $250 a month, scored
36 programs on this list
Compounded tirzepatide programs in all 50 states, scored
39 programs on this list
Providers that offer Tirzepatide
- SnagRx review →Visit site →
SnagRxPartner
You want compounded semaglutide or tirzepatide at one flat price for every dose, with the pharmacies named, and you're happy to pay month to month or commit to a longer plan up front.
- Eden review →Visit site →
EdenPartner
You want a compounded GLP-1 at one flat price that won't rise with your dose, with labs and round-the-clock messaging included and no membership.
- Embody review →Visit site →
EmbodyPartner
You're sure you want a compounded GLP-1, you like a price that holds at every dose, and you want the pharmacies and the doctor network named before you start.
- altRx review →
altRx
You want compounded semaglutide or tirzepatide at one flat monthly price that doesn't rise with your dose, and you're settled enough on treatment that a no-refund policy won't bite.
- Pepti review →
Pepti
You want to see every dose's price before you commit, like a named pharmacy, and are comfortable with an online-only physician review and 28-day billing.
Frequently asked
- Is tirzepatide the same as Zepbound?
- Zepbound contains tirzepatide. It's the brand approved for weight management and obstructive sleep apnea in adults with obesity.
- Is tirzepatide the same as Mounjaro?
- Mounjaro also contains tirzepatide. It's the brand approved for type 2 diabetes and, since August 2026, for lowering heart-event risk in high-risk adults with type 2 diabetes.
- What is the brand name of tirzepatide?
- It has two: Mounjaro and Zepbound, both made by Eli Lilly. Compounded versions sold under program names are not either brand.
- Is there a tirzepatide pill?
- No approved one. Compounded oral products exist but are unapproved and untested. Lilly's GLP-1 pill, Foundayo, contains a different drug, orforglipron.
- How does tirzepatide work for weight loss?
- It acts on GIP and GLP-1 receptors, including in brain areas that control appetite, so people eat less. It also slows stomach emptying. The label says more fat than lean mass is lost.
- Is orforglipron the same as tirzepatide?
- No. Orforglipron (Foundayo) is a different molecule that acts only on GLP-1 receptors and is taken as a daily tablet. Tirzepatide is a weekly injection that acts on GIP and GLP-1.
Sources
- [1] Zepbound (tirzepatide) injection, prescribing information (2026). DailyMed label
- [2] Mounjaro (tirzepatide) injection, prescribing information (2026). DailyMed label
- [3] Foundayo (orforglipron) tablets, prescribing information (2026). DailyMed label
- [4] Drugs@FDA: Mounjaro, NDA 215866 (2026). FDA
- [5] Mounjaro supplement approval letter S-044/S-045 (2026). FDA
- [6] FDA approves new medication for chronic weight management (2023). FDA
- [7] FDA approves first medication for obstructive sleep apnea (2024). FDA
- [8] FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize (2026). FDA
- [9] FDA's concerns with unapproved GLP-1 drugs used for weight loss (2026). FDA
- [10] LillyDirect: Zepbound self-pay pricing (2026). Company website
- [11] LillyDirect: Mounjaro self-pay pricing (2026). Company website
- [12] Jastreboff AM. Tirzepatide Once Weekly for the Treatment of Obesity (2022). PMID 35658024
- [13] Aronne LJ. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity (2025). PMID 40353578
- [14] Aronne LJ. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial (2024). PMID 38078870
- [15] Malhotra A. Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity (2024). PMID 38912654
- [16] Frías JP. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (2021). PMID 34170647
- [17] Nicholls SJ. Cardiovascular Outcomes with Tirzepatide versus Dulaglutide in Type 2 Diabetes (2025). PMID 41406444