Zepbound FAQ: Doses, Weight Loss, Side Effects, Storage and Cost
Zepbound (tirzepatide) is approved for weight loss and for moderate to severe sleep apnea in adults with obesity. In trials, people lost up to 20.9% of body weight at 15 mg over 72 weeks; self-pay prices start at $299 per month.
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Zepbound (tirzepatide) is an injectable prescription medicine approved for two uses in adults: long-term weight reduction in people with obesity, or overweight with at least one weight-related health condition, and the treatment of moderate to severe obstructive sleep apnea (OSA) in adults with obesity. Both uses are alongside a reduced-calorie diet and increased physical activity [1]. The original New Drug Application 217806 was approved on November 8, 2023, and the OSA indication was added through a supplement approved on December 20, 2024 [2].
This page answers the questions people search most: what the label says about dosing, what weight loss looked like in the trials, which side effects are most common, what changed in the February 2026 label, how the four devices differ, the storage limits, and what the drug costs by route. The label was most recently revised in August 2026, with the latest efficacy-labeling supplement (S-041) approved on August 26, 2026 [1][2].
What is Zepbound used for?
The label lists two indications, both in combination with a reduced-calorie diet and increased physical activity: reducing excess body weight and keeping it off long term in adults with obesity, or adults with overweight who also have at least one weight-related comorbid condition; and treating moderate to severe OSA in adults with obesity [1].
There is one stated limitation of use: Zepbound contains tirzepatide, and coadministration with other tirzepatide-containing products or with any GLP-1 receptor agonist is not recommended [1].
What is tirzepatide and how does it work?
Tirzepatide is a GIP receptor and GLP-1 receptor agonist. Lilly markets it as the first and only dual GIP/GLP-1 obesity medication, which is a manufacturer claim [1][5]. GLP-1 is a physiological regulator of appetite and caloric intake, and nonclinical studies suggest the addition of GIP may further contribute to the regulation of food intake. Both receptor types are found in areas of the brain involved in appetite regulation [1].
The molecule contains a C20 fatty diacid that enables albumin binding and prolongs the half-life, which is approximately 5 days. That supports once-weekly injection at any time of day, with or without meals. Tirzepatide lowers body weight with greater fat mass loss than lean mass loss [1].
The same molecule is sold as Mounjaro; Lilly’s authenticity-checking tool covers both brands [10].
What is the Zepbound maintenance dose?
The label’s escalation schedule starts at 2.5 mg injected subcutaneously once weekly for 4 weeks, then increases to 5 mg, with further 2.5 mg increases allowed after at least 4 weeks on the current dose [1].
The 2.5 mg dose is for treatment initiation only and is not approved as a maintenance dose [1][5]. The approved maintenance doses are 5 mg, 10 mg, or 15 mg once weekly for weight reduction and long-term maintenance, and 10 mg or 15 mg once weekly for OSA. The maximum dose for all indications is 15 mg weekly [1].
The label says to consider treatment response and tolerability when selecting the maintenance dosage, and to consider a lower maintenance dosage if a patient does not tolerate one [1].
What happens if you miss a weekly dose?
The label says to inject the missed dose as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip the missed dose and take the next dose on the regularly scheduled day [1].
The day of the week can be changed as long as at least 3 days (72 hours) pass between the two doses, and two doses should never be taken within 3 days of each other [1]. Zepbound is injected subcutaneously in the abdomen or thigh, or by another person into the back of the upper arm, with rotation of injection sites. It should not be injected into muscle or a vein [1]. In the event of an overdose, the label directs people to contact the Poison Help Line at 1-800-222-1222 [1].
How much weight can you lose on Zepbound?
In Study 1, a 72-week trial in adults with obesity or overweight without type 2 diabetes, mean body weight fell 3.1% on placebo, 15.0% on 5 mg, 19.5% on 10 mg, and 20.9% on 15 mg. Baseline mean weights ranged from 102.9 to 105.8 kg [1]. Lilly translates those results to pounds: 34 lb on 5 mg, 44 lb on 10 mg, 48 lb on 15 mg, and 7 lb on placebo, with average starting weights of 226.8 to 233.3 lb [5].
The share of Study 1 patients losing at least 5% of body weight was 34.5% on placebo, 85.1% on 5 mg, 88.9% on 10 mg, and 90.9% on 15 mg. The share losing at least 20% was 3.1%, 30.0%, 50.1%, and 56.7%, respectively [1].
In Study 2, which enrolled adults who also had type 2 diabetes, mean weight change was -3.2% on placebo, -12.8% on 10 mg, and -14.7% on 15 mg, with at least 5% weight loss in 32.5%, 79.2%, and 82.8% of patients, respectively [1].
Lilly also reports SURMOUNT-5, a 72-week open-label study comparing Zepbound with injectable Wegovy (semaglutide): 20.2% (50 lb) average loss on Zepbound at the maximum tolerated dose versus 13.7% (33 lb) on Wegovy at its maximum tolerated dose. Lilly itself describes the data as collected in a less rigorous study, so the findings are less certain, and notes that factors beyond the studied medications may have contributed [5].
Does the weight come back if you stop taking it?
Study 4 tested this directly. After a 36-week open-label lead-in on Zepbound, during which patients lost an average of 20.9% of body weight, they were randomized to either continue Zepbound or switch to placebo through Week 88 [1].
From Week 36 to Week 88, the placebo group regained an average of 14.0% of body weight, while the group that continued Zepbound lost a further 5.5%, a difference of -19.4 percentage points [1].
The OSA trials, Studies 5 and 6, ran 52 weeks. The apnea-hypopnea index (AHI) fell by 25.3 events per hour with Zepbound versus 5.3 on placebo among patients not using PAP therapy (Study 5), and by 29.3 versus 5.5 among patients on PAP therapy (Study 6). Weight fell 17.7% and 19.6% with Zepbound versus 1.6% and 2.3% on placebo. Remission or mild non-symptomatic OSA was achieved by 42.2% versus 15.9% in Study 5 and 50.2% versus 14.3% in Study 6 [1].
What are the most common Zepbound side effects?
Gastrointestinal effects dominate. In pooled data from Studies 1 and 2, any gastrointestinal adverse reaction occurred in 56% of patients at each Zepbound dose versus 30% on placebo. Most nausea, vomiting, and diarrhea events happened during dose escalation and decreased over time [1].
| Adverse reaction | 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% |
| Abdominal pain | 5% | 9% | 9% | 10% |
| Dyspepsia | 4% | 9% | 9% | 10% |
| Injection site reactions | 2% | 6% | 8% | 8% |
| Fatigue | 3% | 5% | 6% | 7% |
| Hair loss | 1% | 5% | 4% | 5% |
Source: Table 1, pooled Studies 1 and 2 [1].
Permanent discontinuation due to adverse reactions occurred in 4.8% of patients on 5 mg, 6.3% on 10 mg, and 6.7% on 15 mg, versus 3.4% on placebo, mostly during the first few months of treatment and mostly for gastrointestinal reasons [1]. Hair loss was associated with weight reduction and was reported in 7.1% of women versus 0.5% of men on Zepbound [1].
What are the boxed warning and other serious warnings?
Zepbound carries a boxed warning: tirzepatide causes thyroid C-cell tumors in rats, in a dose- and treatment-duration-dependent manner, and it is unknown whether it causes such tumors, including medullary thyroid carcinoma (MTC), in humans. Patients are counseled to report symptoms such as a neck mass, trouble swallowing, trouble breathing, or persistent hoarseness [1].
Zepbound is contraindicated in people with a personal or family history of MTC, in those with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), and in anyone with known serious hypersensitivity to tirzepatide or its excipients [1].
Other warnings in the label include severe gastrointestinal adverse reactions (not recommended in patients with severe gastroparesis), acute kidney injury from volume depletion, acute gallbladder disease, acute pancreatitis, hypersensitivity reactions, hypoglycemia when used with insulin or an insulin secretagogue, diabetic retinopathy complications in patients with type 2 diabetes, and pulmonary aspiration during general anesthesia or deep sedation [1]. Severe gastrointestinal reactions were reported in 1.7%, 2.5%, and 3.1% of patients on 5, 10, and 15 mg versus 1% on placebo [1].
The label also states that oral hormonal contraceptives may be less effective with Zepbound; users are advised to switch to a non-oral method or add a barrier method for 4 weeks after starting and after each dose escalation. Zepbound may cause fetal harm, and the label says to discontinue it when pregnancy is recognized. A pregnancy exposure registry is available through 1-800-LillyRx [1][5].
Did Zepbound remove the suicide warning?
Yes. The FDA had flagged suicidal ideation as a newly identified safety signal for the GLP-1 receptor agonist class in a letter dated July 21, 2023. On January 13, 2026, the FDA sent Lilly a supplement request letter asking for the removal of that information from the Zepbound label [3].
The removal was folded into supplement S-042, approved February 25, 2026: subsection 5.9, Suicidal Ideation and Behavior, was deleted from the Warnings and Precautions section, and “depression or thoughts of suicide” was deleted from the Medication Guide’s list of possible side effects [3]. The label’s Recent Major Changes box confirms the removal, dated 02/2026 [1].
The same S-042 supplement also added language following an April 28, 2025 safety signal notification and an October 14, 2025 supplement request letter on intestinal obstruction and fecal impaction: a statement that severe gastrointestinal adverse reactions have been reported postmarketing with GLP-1 receptor agonists (section 5.2), and the addition of “intestinal obstruction, severe constipation including fecal impaction” to the postmarketing experience section [3][1]. The Recent Major Changes box also lists section 5.2 revised 02/2026, section 5.8 revised 08/2026, and section 5.10 added 01/2026 [1].
Some older Lilly materials, including a December 2025 release and a February 2026 release, still listed “depression or thoughts of suicide” in their safety summaries [5][13].
What devices does Zepbound come in?
There are four presentations. The single-dose pen (autoinjector) and single-dose vial each deliver 0.5 mL per dose and come in all six strengths: 2.5, 5, 7.5, 10, 12.5, and 15 mg. Their excipients are sodium chloride, sodium phosphate dibasic heptahydrate, and water for injection. The pen has a built-in needle; the vial requires a syringe and needle, with a new one used each time [1][7].
The multi-dose vial and the single-patient-use KwikPen each contain 2.4 mL, providing four 0.6 mL doses. In addition to the excipients above, they contain benzyl alcohol, glycerin, and phenol as inactive ingredients. The KwikPen contains additional volume to allow for device priming [1].
On the approval timeline: the multi-dose vial formulation supplement (S-037) was approved January 7, 2026; the KwikPen supplement (S-002) was approved January 20, 2026, covering six presentations with four fixed doses each; and Lilly announced the KwikPen launch on February 23, 2026 [2][4][5].
The label states that the KwikPen is not recommended for self-administration by patients who are visually impaired, and that when a patient’s prescribed presentation changes, they and their caregivers should receive training appropriate for the new device [1].
Can you share a Zepbound KwikPen?
No. Section 5.10 of the label, added in January 2026, says to never share a Zepbound KwikPen between patients, even if the pen needle is changed, because sharing poses a risk of transmission of blood-borne pathogens [1]. The Medication Guide likewise says not to give Zepbound to other people, even if they have the same condition [1].
On leftover medicine: the KwikPen instructions say to discard the pen after 4 weekly doses or 30 days after first use, and that attempting to inject leftover medicine could result in an incomplete dose even though the pen still has liquid in it [1]. A single-dose vial should be discarded after use even if medicine remains [1].
What are the Zepbound storage rules?
All presentations share some rules: do not freeze, discard if frozen, protect from heat and light, and keep the medicine in its original carton. The solution should be clear and colorless to slightly yellow, with no particles [1]. The single-dose pen instructions state that it is not necessary to warm the pen to room temperature before use [1].
| Presentation | Refrigerated | Room temperature (up to 86°F / 30°C) | Discard when |
|---|---|---|---|
| Single-dose pen or single-dose vial | 36°F to 46°F (2°C to 8°C) | Up to a total of 21 days | After a total of 21 days at room temperature [1] |
| Unopened multi-dose vial or KwikPen | Until the expiration date on the label | Up to 30 days | After 30 days at room temperature [1] |
| Opened multi-dose vial or KwikPen | 36°F to 46°F, in original carton | Up to 30 days | After a total of 30 days at room temperature, 30 days after first use, or 4 weekly doses, whichever comes first [1] |
How much does Zepbound cost without insurance?
The list price, also called the wholesale acquisition cost (WAC), is $499 to $1,086.37 per fill, based on AnalySource data accessed January 1, 2026. That is the price at which Lilly sells to wholesalers, not what patients pay; what patients pay depends largely on their insurance [6].
For self-pay through LillyDirect, a 28-day month is defined as 4 single-dose vials or 1 KwikPen. The direct-to-patient prices are $299 for 2.5 mg, $399 for 5 mg, $499 for 7.5 mg, and $699 for 10 mg, 12.5 mg, and 15 mg [6][7][8].
The Zepbound Self Pay Journey Program offers $449 for a one-month supply of the 7.5 mg to 15 mg vial or KwikPen, starting with purchases from February 23, 2026, as long as each refill is bought within 45 days of the previous delivery. Otherwise the regular price applies [8][7]. Lilly lowered vial prices on December 1, 2025: 2.5 mg from $349 to $299, 5 mg from $499 to $399, and 7.5 mg to 15 mg from $499 to $449, with non-program prices at that time of $599, $699, $849, and $1,049 for 7.5, 10, 12.5, and 15 mg respectively [13].
On channels: LillyDirect says the single-dose vial is self-pay only and exclusive to LillyDirect, while the KwikPen can be bought with select insurance or self-pay. Pen needles or syringes are sold separately, and delivery is free [7].
What savings programs exist, and do they work with Medicare?
For commercially insured patients whose plan covers the single-dose pen, the savings card offers the pen for as little as $25 for a 1-, 2-, or 3-month fill, with maximum savings of $100, $200, or $300 per fill respectively, up to $1,300 per calendar year, up to 13 fills, and an expiration of December 31, 2026 [8].
For a commercial plan that does not cover the single-dose pen, the card brings the price to as low as $499 per month, with maximum monthly savings equal to the wholesale acquisition cost minus $499, up to 13 fills. For a commercial plan that does not cover the KwikPen, the card prices are $299, $399, $449, and $449 by strength, with maximum monthly savings of $215, $115, $65, and $271, and up to 11 fills [8].
Card eligibility requires being 18 or older, a resident of the United States or Puerto Rico, and not being enrolled in any government program such as Medicare, Medicaid, or TRICARE. The card is not insurance, and Lilly may change its terms at any time without notice [8][6]. A separate KwikPen Self-Pay Savings Card is for cash-paying patients only, covers the KwikPen only, and cannot be used with reimbursement from any payer; it can be used at pharmacies other than LillyDirect [8][9].
For Medicare beneficiaries, the Medicare GLP-1 Bridge program starts July 1, 2026 and offers Zepbound for $50 per month, KwikPen only; the single-dose pen and vials are not covered under it. Requirements include Part D coverage, age 18 or older, no type 2 diabetes, OSA, or fatty liver disease, and a BMI of 35 or higher, or 30 or higher with specified conditions such as certain heart failure, hard-to-control high blood pressure, or stage 3a-or-above chronic kidney disease, or 27 or higher with prediabetes or a prior heart attack, stroke, or blocked arteries in the limbs. A doctor submits an approval form, and the $50 payment does not count toward the Part D deductible or the yearly out-of-pocket limit [12].
Can children take Zepbound, and how do you check a package is real?
The label states that safety and effectiveness in pediatric patients have not been established [1][5]. In pooled Studies 1 and 2, 9% of Zepbound-treated patients were 65 or older and 0.5% were 75 or older, with no overall differences observed compared with younger adults. No dose adjustment is recommended for renal or hepatic impairment [1].
To verify a package, Lilly’s tool at scan.lilly.com lets you scan the 2D barcode printed on the outside of the carton with a smartphone; it checks the serial number against Lilly’s United States-made supply. The pen or vial itself cannot be scanned [10]. The free Lilly Health app offers savings card information, dose tracking, and device syncing, and Lilly states it is not intended for treatment decisions. A digital starter kit is available by texting “ZB” to 85099, and how-to videos cover the pen, vial, and KwikPen [11].
Lilly claims Zepbound is the #1 prescribed injectable obesity medication, that 1 in 3 new branded weight-management starts in 2025 were Zepbound self-pay vials, and that over 1 million patients accessed Lilly treatments through LillyDirect in 2025. These are manufacturer figures [5].
Sources
- National Library of Medicine. DailyMed: ZEPBOUND (tirzepatide) injection, solution.
- US Food and Drug Administration. Drugs@FDA: New Drug Application 217806, Zepbound (tirzepatide).
- US Food and Drug Administration. Supplement approval letter, NDA 217806/S-042, Zepbound (tirzepatide) injection.
- US Food and Drug Administration. Supplement approval letter, NDA 217806/S-002, Zepbound KwikPen (tirzepatide) injection.
- Eli Lilly and Company. Zepbound (tirzepatide), the most prescribed weight management medication in 2025, now available in multi-dose KwikPen. February 23, 2026.
- Eli Lilly and Company. Zepbound cost information: with or without insurance.
- Eli Lilly and Company. Authentic Zepbound (tirzepatide) shipped to you: LillyDirect.
- Eli Lilly and Company. Zepbound (tirzepatide): full terms and conditions.
- Eli Lilly and Company. Savings and insurance options: Zepbound (tirzepatide).
- Eli Lilly and Company. Check the authenticity of your Zepbound (tirzepatide) and Mounjaro (tirzepatide) medication.
- Eli Lilly and Company. Resources, support, tips and guides: Zepbound (tirzepatide).
- Medicare. Fact sheet: Medicare GLP-1 Bridge, GLP-1 drugs for $50 a month. July 1, 2026.
- Eli Lilly and Company. Lilly lowers the price of Zepbound (tirzepatide) single-dose vials. December 1, 2025.
Frequently asked questions
What is the difference between Zepbound and Mounjaro?
Both contain the same molecule, tirzepatide, and Lilly's authenticity-checking tool at scan.lilly.com covers both brands. Zepbound's label covers two adult indications, both alongside a reduced-calorie diet and increased physical activity: long-term weight reduction in adults with obesity, or overweight with at least one weight-related comorbid condition, and moderate to severe obstructive sleep apnea in adults with obesity.
Does 7.5 mg or 12.5 mg count as a maintenance dose?
The label lists approved maintenance doses of 5 mg, 10 mg, or 15 mg once weekly for weight reduction, and 10 mg or 15 mg for OSA, with 15 mg the maximum for all indications. The 2.5 mg dose is for initiation only and is not approved as maintenance. Doses are increased in 2.5 mg steps after at least 4 weeks on the current dose.
How long do single-dose pens last out of the fridge?
Single-dose pens and single-dose vials are stored in a refrigerator at 36°F to 46°F (2°C to 8°C). If needed, each can be kept unrefrigerated at up to 86°F (30°C) for a total of 21 days, and it must be discarded after that. Do not freeze, and store in the original carton to protect from light.
Why does a KwikPen have liquid left after four doses?
Each single-patient-use KwikPen contains 2.4 mL for four 0.6 mL doses, plus additional volume to allow for device priming. The instructions say to discard the pen after 4 weekly doses or 30 days after first use, because attempting to inject the leftover medicine could result in an incomplete dose.
Does the Zepbound savings card work with Medicare?
No. Card eligibility excludes anyone enrolled in a state, federal, or government-funded healthcare program, including Medicare, Medicare Part D, Medicare Advantage, Medigap, Medicaid, DoD, VA, and TRICARE. Medicare beneficiaries may instead qualify for the Medicare GLP-1 Bridge, which starts July 1, 2026 and offers the Zepbound KwikPen for $50 per month to eligible Part D patients.
Can the Zepbound vial be bought at a retail pharmacy?
LillyDirect states that the single-dose vial is self-pay only and exclusive to LillyDirect, with free delivery. The KwikPen, by contrast, can be bought through LillyDirect with select insurance or self-pay, and the KwikPen Self-Pay Savings Card can be used at pharmacies other than LillyDirect.
What should you do about a missed weekly dose?
The label says to inject the missed dose as soon as possible within 4 days (96 hours). If more than 4 days have passed, skip the missed dose and take the next dose on the regularly scheduled day. Two doses should never be taken within 3 days (72 hours) of each other.
Does the weight return after stopping Zepbound?
In Study 4, patients lost an average of 20.9% of body weight during a 36-week open-label period. Those switched to placebo then regained an average of 14.0% by Week 88, while those who continued Zepbound lost a further 5.5%, a difference of -19.4 percentage points.
This article summarizes FDA labeling, published research and company information current as of September 14, 2026. It is not medical advice and does not replace a conversation with your own healthcare provider. How we research and verify.