Zepbound
tirzepatide · dual GIP/GLP-1 receptor agonist
Zepbound is once-weekly tirzepatide, FDA-approved for chronic weight management and for moderate-to-severe obstructive sleep apnea in adults with obesity. It produced the largest mean weight loss of any FDA-approved obesity medication in trials, about 21% at the highest dose. Doses step up from 2.5 mg to 15 mg. Common side effects are gastrointestinal, and a boxed warning covers thyroid C-cell tumor risk. List price is about $1,086/mo, with LillyDirect self-pay vials starting at $299/mo.
GIP/GLP-1 RA
Once weekly
~21%
$1,086/mo
Overview
Zepbound is the brand name for tirzepatide dosed and labeled for weight management, made by Eli Lilly. It is the same active drug as Mounjaro, with a different label and a weight-loss indication rather than a diabetes one. It activates two receptors, GIP and GLP-1, and in the SURMOUNT-1 trial the 15 mg dose produced an average 20.9% body-weight reduction, the highest weight-loss outcome of any FDA-approved obesity medication. It is prescribed alongside a reduced-calorie diet and increased physical activity.
How Zepbound works
Curbs appetite
Slows digestion
Improves sleep apnea
What it's used for
- Chronic weight management in adults with a BMI of 30 or higher, or 27 or higher with a weight-related condition
- Moderate-to-severe obstructive sleep apnea in adults with obesity
- Used alongside a reduced-calorie diet and increased physical activity
- Not FDA-approved for type 2 diabetes; Mounjaro is the tirzepatide product carrying that indication
Effectiveness
In SURMOUNT-1, tirzepatide produced about 20.9% mean body-weight loss at the 15 mg dose over 72 weeks. In SURMOUNT-5, the head-to-head trial against semaglutide 2.4 mg, tirzepatide produced greater mean weight loss. In SURMOUNT-OSA, it substantially reduced the apnea-hypopnea index alongside weight loss, which is the basis for the sleep apnea indication. Results build gradually across the dose escalation. Individual results vary.
Dosing schedule
Dose increases happen in 2.5 mg increments after at least 4 weeks at the current dose. Zepbound is sold as single-dose vials and as a prefilled KwikPen; the vials are the format offered at reduced self-pay pricing.
Side effects & Safety
Common side effects
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Abdominal pain
- Injection-site reactions
- Fatigue
Serious risks & warnings
- Thyroid C-cell tumor risk (boxed warning)
- Pancreatitis
- Gallbladder problems
- Low blood sugar with insulin/sulfonylureas
- Kidney injury from dehydration
- Severe gastrointestinal reactions
- Pulmonary aspiration during general anesthesia or deep sedation
- Monitor for depression or suicidal thoughts
Do not use with a personal or family history of medullary thyroid carcinoma or MEN 2. Not for use during pregnancy.
Cost & savings
List price is about $1,086/mo for the KwikPen without insurance. Most people pay less through one of these routes:
Through insurance
Varies
Telehealth cash-pay
$99/mo
Manufacturer directFrom $299/mo
The $449 rate on 7.5 mg and higher holds only inside the LillyDirect Self Pay Journey Program, which requires each refill within 45 days of your previous delivery. If a refill lapses past day 45, pricing reverts to $499 for 7.5 mg and $699 for 10, 12.5, and 15 mg. Self-pay cannot be combined with commercial insurance, Medicare, or Medicaid. Prices verified August 2026.
Compare with other GLP-1s
Frequently asked questions
How much weight can you lose on Zepbound?
In SURMOUNT-1, mean loss was about 20.9% of body weight at the 15 mg dose over 72 weeks. That is a trial average across a large group; some people lose considerably more or less.
Is Zepbound better than Wegovy?
In SURMOUNT-5, the head-to-head trial, tirzepatide produced greater mean weight loss than semaglutide 2.4 mg. Tolerability, insurance coverage, and cost still make Wegovy the better fit for some people.
Does insurance cover Zepbound for sleep apnea?
Coverage for the obstructive sleep apnea indication is generally broader than for obesity alone, including under Medicare Part D. Requirements vary by plan.
What is the difference between Zepbound vials and the KwikPen?
Same medication. Vials require drawing the dose with a syringe and are the format sold at reduced self-pay prices through the manufacturer. The KwikPen is prefilled and is what retail pharmacies typically stock.
What happens if I stop taking Zepbound?
In the SURMOUNT-4 withdrawal study, participants who stopped regained a substantial share of the weight they had lost. Zepbound is labeled for long-term use.
Educational only, not medical advice. Zepbound is a prescription medication; a licensed clinician determines if it's appropriate. Effectiveness figures are trial averages (SURMOUNT); results vary. Pricing verified August 2026 and subject to change. *Starting price for doctor-guided care; medication cost is separate.