Yes, Zepbound Vials Are Overfilled and Other FAQs
- Jennifer Hardy
- Jul 19
- 6 min read
Zepbound’s popularity and high price point mean more people are swapping from prefilled pens to multi‑dose vials through LillyDirect. The switch sounds simple until you open the box, see the liquid level, and wonder if you’re missing something.
Is there really enough for all your doses? Why does it look like extra is left over? Why isn't the new dose a larger portion? These are some of the most common questions we hear, so let’s tackle them one by one.
Understanding the Basics of Zepbound Vials
Whether you're a first-time user of vials or just switched to them from an autoinjector (or got left behind in the CVS/Wegovy collab), staring at a vial, needle, and supplies can be daunting.
If you're afraid of needles, as I was, that adds a whole new layer of anxiety. Let's ease into this topic with the basics, and then we'll expand on each one.
A one-month supply of Zepbound comes with four vials to be injected weekly.
Each vial is a single dose. They can range in medication amounts from 2.5 mg/0.5 mL to 15mg/0.5 mL.
Zepbound vials are overfilled by design, which is standard practice in the pharmaceutical industry.
A syringe with a needle can be purchased with the Zepbound vials through Gifthealth. That will cost $5. They send a couple of extra just in case. You can also buy your own for a better value. Look for 0.5 mL single-use in bulk.
Zepbound vials are sent in a styrofoam container with ice packs to keep them cold. Put them in the fridge (not the freezer) as soon as they arrive.
Why Zepbound Vial Dosages All Have the Same Amount of Fluid
One thing that throws a lot of people off is the amount of liquid in each vial. Every Zepbound vial is filled with the same total volume of solution — about 0.5 mL — no matter what dose your prescription calls for.
The difference between a 2.5 mg vial and a 15 mg vial isn’t the amount of liquid; it’s the concentration of the medication suspended in that liquid. The vials each have different colors on the caps and boxes to distinguish between them.
Dose | Cap/Label Color |
2.5 mg | Gray |
5 mg | Purple |
7.5 mg | Blue-green/Teal |
10 mg | Pink |
12.5 mg | Orange |
15 mg | Yellow |
It's important to know that you aren't getting shortchanged when the vial size and liquid amount stay the same. The colorless fluid is just more concentrated at higher doses.
Are Zepbound Vials Overfilled?
These vials are also slightly overfilled on purpose. This is a common FDA-sanctioned practice called "Allowable Excess Volume." Here's why that is done:
To make sure you can withdraw the full labeled dose even if a small amount stays in the needle or syringe.
To account for tiny losses that happen when priming the syringe or handling the vial.
To maintain accurate dosing despite normal manufacturing variations in fill levels.
To ensure patient safety by preventing under‑dosing due to unavoidable residual liquid.
To comply with USP (United States Pharmacopeia) standards that require a minimum extractable volume beyond the labeled amount.
As long as you’ve drawn the liquid up to the correct measurement line on your syringe, 0.5 mL for every Zepbound dose, you’ve got the full amount you need. Don’t try to pull extra fluid from the vial just because you see more left.
While the documentation for Zepbound doesn't detail this, Eli Lilly does clarify this with Mounjaro, which is just a different dosage of tirzepatide for diabetes patients.
"Mounjaro solution is placed in a 3 mL single dose vial which is slightly overfilled so that the 0.5 mL dose may be removed for administration. Throw away all opened vials after use, even if there is medicine left in the vial."
How to Choose the Right Syringe and Needle for Zepbound Vials
I'm a fan of the easy way, so I just let Eli Lilly send me the needles needed for the medication. Given that I was terrified of needles, I wasn't one to go shopping for them on my own. Even having a conversation with a pharmacist might have made me woozy.
What a fool I was! After a whole bunch of anxiety and amping myself up for the first shot, I was baffled when it didn't hurt one bit. In fact, I still watch the needle go in just to be sure I'm not missing the mark. It's just that painless. I think only one time did I feel anything even close to a pin prick.
If you buy your own syringes and needles, look for a 0.5 mL insulin‑type syringe with a fine needle, typically 29–31 gauge and 5/16 inch (8 mm) in length.
The syringes used for Zepbound are very small compared to what most people picture when they think of needles. The 29–31 gauge means they’re extremely thin (the higher the gauge number, the thinner the needle).
The length is usually 5/16 of an inch (about 8 mm), designed to go just under the skin into subcutaneous fat rather than deep into muscle. Unlike some other injectables, like birth control, that go right into the muscle, you want to avoid that with Zepbound.
The approved injection sites are:
Front of the thighs
Abdomen (stomach area), at least two inches away from the belly button
Outer upper arms (if someone else is giving the injection)
How to Fill the Zepbound Vial Syringe
It took me a few tries to get it right, but the packaging details how to get the full volume of liquid, and it's just one quick step.
Before you put the needle in the vial, pull the stopper all the way back. This will fill the syringe with air. Then, put the needle in the vial and push the air inside. From there, you'll hold the vial sideways and slowly pull back as the liquid fills up the syringe.
If there's air at the top, give it a few taps and let that air out, and scoop up more liquid. Then, you can pull the needle out to inject.
Zepbound Vials Storage: Temperatures and Climate Control
If you left your vials in a hot car or forgot to open the shipping box right away, don’t panic, but don’t inject until you know the facts. Zepbound vials are meant to be kept cold, stored in the refrigerator between 36°F and 46°F.
Let's say you forget to put the Zepbound vials in the refrigerator. It's important to know that Zepbound can sit at room temperature up to 86°F (30°C) for a total of 21 days. Once the Zepbund vials reach room temperature, don't put them back in the fridge. Use those doses first (and within 21 days).
If a vial ever gets frozen, even a little, it’s done. The same goes for one that sat somewhere hotter than 86°F. High temperatures can irreversibly degrade tirzepatide. Once its structure is damaged by heat, cooling it back down will NOT restore its effect. The biggest concern is potency when the med gets too cold or hot, but there's also the instability with unknown risk factors. It's just not worth it.
I also want to add, you're not alone if this happens. I've seen dozens of questions in subreddits about this topic. Eli Lilly is known to be understanding about this happening, but don't press your luck more than once.
Start by calling your pharmacist and explaining the situation.
Reach out to Eli Lilly customer service at 1-800-545-5979
Be honest about any mistakes you made
There are a lot of reports about one-time forgiveness on this, but be respectful, nice, and patient when you're trying to get the problem squared away.
Always Use a Sharps Container
You'll need to purchase a sharps container to dispose of the needles and vials. I found one that's small, simple, and easy to store for less than $10. In fact, you can get three of them for less than $15.
You can also use an empty detergent bottle, but be sure to mark it as medical waste and let your family know what's in there.
Sharps disposal and medical waste laws vary by city, so check yours before you start the Zepbound journey. You can't just toss this stuff in the regular trash.
What Else Can I Tell You About Zepbound Vials?
I started my Zepbound journey about six months ago. I was so anxious about, well, all of it, that I did a ton of research. Those investigative journalism skills were put to good use! That's how GLP-1 Newsroom was born; I just wanted to share the information I found with others. If you have a question, send me an email or leave a comment below.
You can also sign up for the GLP-1 Newsroom newsletter to get updates on product reviews, news, and developments.
