What Tirzepatide is
Tirzepatide acts on two gut hormone receptors, GIP and GLP-1. Together they increase insulin release after meals, slow stomach emptying, and reduce appetite. It is made by Eli Lilly.
It is sold under two brand names for different approved uses.
Weekly injection. Type 2 diabetes.
Weekly injection, as a pen or single-dose vial. Chronic weight management and moderate to severe obstructive sleep apnea in adults with obesity.
Regulatory status in 2026
Brand-name tirzepatide is FDA-approved and prescription only. Compounded and "research" versions are where the risk sits.
Mounjaro approved for type 2 diabetes.
Zepbound approved for chronic weight management.
FDA declares the tirzepatide shortage over and approves Zepbound for obstructive sleep apnea.
Compounded tirzepatide is limited to narrow, patient-specific cases. Tirzepatide sold as "research use only" is not legal for human use.
Regulatory status can change. Check the sources linked at the bottom of this page before relying on anything here.
What's proven vs. what's claimed
Tirzepatide's approved uses rest on large randomized trials.
Causes significant weight loss.
Shown in large randomized trials and the basis for Zepbound's approval.
Strong human evidenceImproves sleep apnea.
Shown in randomized trials in adults with obesity. Approved for this use.
Strong human evidenceCompounded or research tirzepatide is the same as the brand.
Not evaluated by FDA for quality, strength, or purity.
Insufficient dataStorage and stability
These are the commonly cited label limits for US Mounjaro and Zepbound. Your product's label and pharmacist take priority.
Routine storage
- Refrigerate at 36 to 46°F (2 to 8°C).
- Do not freeze. Don't use a pen or vial that has been frozen.
- Keep in the original carton to protect from light.
Out of the fridge
- Pens and single-dose vials can be kept unrefrigerated at up to 86°F for up to 21 days.
- Once it has been out of the fridge, track the date so you know when the 21 days end.
- Single-dose means single dose. Don't save leftover liquid.
Light exposure is easy to overlook in a fridge door that opens dozens of times a day. VIALTIGHT is building stackable cases that block light from every side. See vialtight.com for updates.
Out-of-fridge clock
An easy storage mistake with pens is losing track of how long one has been out. Pick your product and the date it came out of the fridge (or was first used) to see the last day it's good under the label limit.
Based on commonly cited US label limits. Check your product's label. VialTracker keeps start dates with each pen or vial so you don't have to remember.
Safety flags
Boxed warning: thyroid tumors. Tirzepatide caused thyroid C-cell tumors in rats. It should not be used by people with a personal or family history of medullary thyroid cancer or MEN 2.
Other label warnings. Pancreatitis, gallbladder problems, kidney problems from dehydration, and low blood sugar when combined with insulin or sulfonylureas.
Birth control pills. The label notes tirzepatide may make oral birth control less effective for a period after starting and after each dose increase. Ask your prescriber about backup methods.
"Research" tirzepatide. Products sold online as research chemicals are unapproved and may not contain what the label says.
FAQ
Is Mounjaro the same as Zepbound?
Same active ingredient, different approved uses. Follow the product your prescriber chose.
Can I still get compounded tirzepatide?
Only in narrow cases. The broad shortage exception ended after FDA declared the shortage over.
Does VialTracker tell me what dose to take?
No. Follow your prescriber and the label. VialTracker records what you were prescribed and when you took it.