What you’ll learn:
- Tirzepatide is available in two forms—Mounjaro® and Zepbound®—each with its FDA-approved indications.
- Tirzepatide dosing begins at a low level and gradually increases to maximize the results while minimizing side effects.
- The right dose varies for each person and depends on how your body responds, which is why personalized adjustments with a healthcare provider are so important.
GLP-1 medications are reshaping the weight loss landscape as more people turn to them to lose weight and improve their overall health. But taking them isn’t as simple as swallowing a pill and waiting for results. Most GLP-1s are self-administered injections, and they require a step-up dosing schedule, where you start at a low dose and gradually increase based on how your body responds.
When you begin tirzepatide, the active ingredient in Zepbound® and Mounjaro®, this personalized dosing approach is essential. It helps minimize side effects like nausea or fatigue while supporting steady, sustainable weight loss—ideally around 1 to 2 pounds per week.
Finding the right dose takes time, but it’s critical for long-term success. Clinical trials show that people taking tirzepatide lost an average of 21% of their body weight over 18 months.
Here’s how the dosing process works—and what to expect along the way.
What is tirzepatide?
While you might have heard of Mounjaro® or Zepbound®, you may not be familiar with how the tirzepatide in them works. Tirzepatide mimics the actions of two hormones: GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). These hormones help regulate blood sugar, slow digestion, and reduce appetite. By targeting two pathways, tirzepatide improves insulin sensitivity and promotes a greater feeling of fullness, leading to significant and sustained weight loss for many people.
Though both medications contain the same active ingredient, they differ in their FDA-approved uses and the contexts in which they’re prescribed. Let’s break it down:
What is Zepbound®?
Zepbound® is FDA-approved for weight management in adults with a BMI of 30 or higher, or 27 or higher with at least one weight-related health issue, like high blood pressure or high cholesterol. It can also be prescribed to treat obstructive sleep apnea (OSA).
- How you take it: Once-weekly injection with a prefilled injection pen or a vial and syringe.
- Doses: Zepbound® comes as a prefilled injection pen or vial and syringe combo. The pen is available at most pharmacies with your prescription. You’ll get the vial and syringe form of Zepbound® directly from Eli Lilly, and it costs less for people who don’t have insurance coverage.
- Pen: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg
- Vial and syringe: 2.5 mg, 5 mg, 7.5 mg, 10 mg
What is Mounjaro®?
Mounjaro® is FDA-approved for adults with type 2 diabetes to help manage blood sugar levels. Like Ozempic®, Mounjaro® is often prescribed off-label for weight loss. To qualify for an off-label prescription, you typically need to meet the same BMI markers as for Zepbound®. Mounjaro® is only available as a prefilled injection pen.
- How you take it: Once-weekly injection
- Doses: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg
Finding the right dose of tirzepatide for weight loss
As mentioned, finding the right tirzepatide dosage involves starting low and gradually increasing over several months. While there is a roadmap that many people follow, your path might be different. Your healthcare provider will adjust your dose based on your response, comfort, and progress toward weight loss.
Whether you’re using Zepbound® or Mounjaro®, you’ll start on the lowest dose. Both medications are the same and have the same doses, unless you are using the vial and syringe version of Zepbound®, which only goes up to the 10 mg dose*. Here’s a look at the typical pathway:
- Starting dose: 2.5 mg weekly (weeks 1 through 4)
- Dose escalation:
- Increase as needed and tolerated:
- 5 mg weekly
- 7.5 mg weekly
- 10 mg weekly*
- 12.5 mg weekly
- 15 mg weekly
- Increase as needed and tolerated:
- Maintenance dose: Any dose can be used for maintenance if it works for you.
- Maximum dose: 15 mg once weekly.
*If you need to go higher than the 10 mg dose with the vial and syringe, you’ll have to switch to the injector pens.
Will your costs increase as your tirzepatide dosage goes up?
The cost of the different tirzepatide medications can vary and will increase with the dose if you’re using the vial and syringe option. Let’s go through what you can expect to pay with both.
- Mounjaro®: The monthly cost of a prefilled Mounjaro® pen is about $1,080 and will stay the same across all doses (2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg).
- See our guide on Mounjaro® costs in 2025 for a full breakdown.
- Zepbound®: If you’re using Zepbound®, the cost will depend on whether you choose the prefilled pen or the vial and syringe option through the manufacturer.
- Prefilled pen: The pen has a list price of $1,086 per month; all doses will cost the same amount.
- Vial and syringe: When ordered through the Lilly Direct program, the 2.5 mg vial costs $349 per month, and the 5 mg, 7.5 mg, and 10 mg vials cost $499 per month. If you need to step up to the 12.5 or 10 mg dose, you’ll need to pay the prefilled pen prices. Read more about what Zepbound® will cost you.
Is the dose different for weight loss vs. diabetes
The dose won’t necessarily be different for weight loss or type 2 diabetes management. It will depend on how your body reacts to the medication in terms of weight loss or blood sugar management, balanced against side effects.
In general, people lost more weight at the higher doses of tirzepatide. People also tended to experience greater diabetes management results at higher doses. According to one study, HbA1c reductions were greater with the 10 mg and 15 mg doses of tirzepatide versus the lower doses.
How much weight can I lose with tirzepatide by dose?
You don’t have to get the highest dose of tirzepatide to see significant results. Here’s a look at what the clinical studies show about weight loss at different doses.
In the 72-week trial, people were able to lose an average of the following percentage of weight: 
- 5 mg dose: 15% weight loss
- 10 mg dose: 20% weight loss
- 15 mg dose: 21% weight loss
For someone starting at 200 pounds, this translates to approximately: 
- 5 mg: 30 pounds lost
- 10 mg: 39 pounds lost
- 15 mg: 42 pounds lost
While higher doses typically lead to greater weight loss, they also increase the likelihood of side effects, so your provider will carefully balance effectiveness with comfort.
How to take tirzepatide
Both Mounjaro® and Zepbound® are taken as weekly injections under the skin (subcutaneous) that you give yourself. The difference will be if you use the vial and syringe form with Zepbound®. Here’s what you need to know about each method:
Tirzepatide should always be injected just under the skin, never directly into muscle or veins. Common injection sites include:
- Stomach (abdomen): About two inches away from your belly button.
- Thigh: Upper front or outer area.
- Upper arm: The back side of your upper arm, if someone else is giving you the injection.
Rotating injection sites each week helps reduce irritation and improve absorption. Avoid injecting into areas that are bruised, tender, hard, scarred, or have skin conditions.
| Medication | Instructions | Storage |
|---|---|---|
| Mounjaro® and Zepbound® prefilled pens | 1. Remove the pen from the fridge when ready to use. 2. Check liquid: Make sure it’s clear to slightly yellow, has no particles, and is not cloudy or frozen. 3. Wash your hands and choose the injection site. 4. Pull off the gray base cap (don’t touch or recap the needle). 5. Place the clear base flat on the skin. 6. Turn the lock ring to unlock. 7. Press and hold the purple injection button for up to 10 seconds. 8. First click: injection starts. Second click: injection complete. 9. Check that the gray plunger is visible. 10. Dispose of the pen in an FDA-approved sharps container. 11. Store unopened pens in the fridge (36°F – 46°F). Once opened, keep at room temperature for up to 21 days. Do not freeze; discard if frozen or damaged. | Store unopened pens in the refrigerator (36°F to 46°F). Once opened, pens can remain at room temperature for up to 21 days. Never freeze your pen, and discard it if it is accidentally frozen or damaged. |
| Zepbound® single-dose vials | 1. Remove the vial from the fridge and inspect it. It should be clear or slightly yellow, with no particles, and not cloudy or frozen. 2. Gather supplies: vial, syringe, needle, alcohol swab, gauze, sharps container. 3. Clean the rubber stopper with an alcohol swab. 4. Insert the needle, inject air into the vial, then draw medication. 5. Remove air bubbles from the syringe. 6. Inject into the chosen site and hold the needle in for 5 seconds after the plunger is fully pressed. 7. Dispose of the syringe and needle in a sharps container. | Unused vials should remain refrigerated and can be stored at room temperature (up to 86°F) for up to 21 days. Discard opened or used vials immediately after injection. Read the detailed instructions for using Zepbound® vials for more information. |
Will tirzepatide ever be available as a pill?
While semaglutide has a pill called Rybelsus, tirzepatide is only available as an injection. Eli Lilly is currently testing a GLP-1 pill, called orforglipron. Here’s some early info from testing:
- In the study, people taking orforglipron saw their A1C levels drop by 1.3% to 1.6%, and those on the highest dose lost an average of 16 pounds (7.9%).
- These results are comparable to the popular injectable GLP-1 meds, but in the convenience of a once-daily pill.
The safety profile of orforglipron looks promising, with side effects that were mostly mild to moderate and typical for the GLP-1 class (things like nausea, diarrhea, or constipation). More trial results are expected, including studies on using orforglipron for weight loss, sleep apnea, and high blood pressure. If approved, this GLP-1 pill could offer an alternative to injectable tirzepatide.
Tirzepatide dosage adjustments & personalization
Your healthcare provider will personalize your tirzepatide dose to match your individual health goals, comfort, and response. Zepbound® and Mounjaro® follow similar guidelines for dose adjustments and personalization.
Several factors can affect how your provider adjusts your dosage:
- Body weight: People who want to lose a lot of weight may need a higher dose to achieve desired results. As mentioned, people taking the higher doses tend to lose more weight.
- Side-effect tolerance: Side effects like nausea or fatigue could be more intense at higher doses for some people. One study showed that adverse gastrointestinal effects like nausea and diarrhea were more frequently reported with the 15 mg dose of tirzepatide (49%) versus the 5 mg dose (39%).
Signs you might need a different dose of tirzepatide
Your healthcare provider will adjust your dose depending on how your body responds. Here are a few signs that could mean it’s time to tweak your dose:
- Your weight loss has hit a plateau. If the pounds were coming off, but things have slowed down or stopped, it might be time to move up to the next dose.
- You’re still feeling rough. If side effects like nausea, fatigue, or stomach upset are sticking around, your provider may pause the dose increases or dial it back to give your body more time to adjust.
- Your health situation has changed. Starting a new medication or being diagnosed with another condition could mean your current dose isn’t the best fit anymore. A quick check-in with your provider can help keep everything on track.
Remember: When your dose goes up, you might notice side effects getting a little stronger at first, but for most people, they ease up after a few weeks as your body adjusts.
Timing & administration tips for best weight loss results with tirzepatide
Sticking to your tirzepatide routine—whether you take Mounjaro® or Zepbound®—is the best way to achieve results and manage side effects. Here are some easy tips to make it part of your weekly routine.
| Action | Details |
|---|---|
| When to take it | Take it on the same day each week. Take it any time on that chosen day. Pick a day that fits easily into your routine, like a weekend morning or a quiet evening. Time of day doesn’t affect results. You can take your weekly injection in the morning, afternoon, or evening—whatever works best for you. |
| Where to inject | Inject Zepbound® or Mounjaro® into your upper arm, thigh, or belly, depending on what’s most comfortable for you. Rotate your injection site each week to avoid skin irritation. If you prefer one area, don’t use the same spot every time. |
| How to minimize side effects | Try evening injections: Taking your shot at night might let you sleep through side effects like nausea or fatigue. Pick a low-key day: Injecting on the weekend or a day when you’re less busy gives you space to rest if side effects hit. Watch what you eat: Avoid heavy, greasy, or spicy meals around your injection time. They can make nausea worse. Eating before or after an injection won’t change its effectiveness, but some find that a small meal or snack afterward can help reduce nausea. Stay hydrated: Drinking water before and after your shot can help with common GI issues like nausea or constipation. |
Everyone’s different, so it might take a little trial and error to figure out what works best for you.
What happens if you miss a dose of tirzepatide?
It’s important to keep your dosing schedule with Zepbound® or Mounjaro®, especially since you only take it once a week. If you do miss a dose, here’s what to do depending on your situation:
| Situation | What to do | Why it matters |
|---|---|---|
| If you missed a dose and it’s been ≦4 days | Take the missed dose as soon as you remember and stay on the same schedule for the next dose. | Staying consistent helps keep the medication effective. |
| If you missed a dose and it’s been >4 days | Skip the missed dose and wait until your next scheduled injection. | Taking doses too close together can increase side effects. You should not take more than one dose within 48 hours. To stay safe, always make sure at least 3 days (72 hours) pass between doses. |
| If you miss several doses | Contact your healthcare provider before restarting. | They can guide you safely back onto a safe dosing schedule. |
| Important reminder | Never double up on doses to “catch up.” | Double dosing raises the risk of nausea, vomiting, and low blood sugar (especially if you have diabetes). |
Tirzepatide overdose risks & symptoms
Tirzepatide (whether it’s Mounjaro® or Zepbound®) is a once-weekly injection, which makes it convenient—but also easy to lose track of if your routine changes. An accidental overdose can happen if you forget you already took your dose, confuse the day, or misread instructions, especially when starting out. Taking too much can lead to serious side effects that may last for days.
You might experience:
- Severe nausea or vomiting that doesn’t go away
- Ongoing diarrhea or sharp stomach pain
- Extreme dizziness, confusion, or feeling faint
- Unusual tiredness or weakness
- A racing heart or intense shakiness
- Strong or sudden symptoms of low blood sugar, like sweating, blurred vision, or trouble thinking clearly
If you think you’ve taken too much or your symptoms feel unusually severe, call the Poison Help Line at 1-800-222-1222 right away. If it’s a medical emergency, call 911.
Because tirzepatide stays in your system for several days (it has a half-life of about 5 days), your healthcare team may need to monitor and treat your symptoms over time. Treatment usually focuses on managing the side effects until the medication clears your system.
To avoid accidental double dosing, try these tips:
- Set a recurring reminder or calendar alert on your phone.
- Mark injection days on a paper calendar or use a medication tracking app.
- Store your pen in a designated spot and only return it there once it’s been used.
- Keep a medication journal or log each dose right after injecting.
Mounjaro® and Zepbound®: Side effects and safety considerations
While tirzepatide is effective and safe for many people, it can come with side effects and has warnings associated with it. Most side effects are mild or moderate and often decrease over time as your body adjusts to the medication, though some can be severe. Let’s take a look at what to watch out for.
Common side effects
The most common side effects typically occur early in treatment or when increasing the dose. They typically improve over time and can include:
- Nausea
- Vomiting
- Diarrhea or constipation
- Stomach pain
- Fatigue
Serious side effects and warnings
Tirzepatide can cause serious side effects, though these are rare. Seek immediate medical attention if you experience any of these:
- Pancreatitis: Symptoms include severe abdominal pain that radiates to your back, with or without vomiting.
- Vision changes: If you notice any sudden changes in your vision while taking tirzepatide, get immediate medical attention.
- Low blood sugar (hypoglycemia): Symptoms include dizziness, shakiness, blurred vision, fast heartbeat, and feeling jittery. Low blood sugar is most likely in people who are also taking medications for diabetes.
- Kidney problems: Diarrhea, nausea, and vomiting can cause dehydration and worsen kidney issues. Go to the ER if you experience decreased urination, swelling in the ankles or legs, fatigue, or shortness of breath.
- Gallbladder problems: Symptoms include upper abdominal pain, fever, jaundice, or clay-colored stools.
- Allergic reaction: Symptoms include swelling of the face, lips, tongue, or throat, difficulty breathing or swallowing, or a rapid heartbeat. If you think you’re having an allergic reaction, get immediate medical attention.
- Thyroid tumors or cancer: Be alert for a lump or swelling in the neck, difficulty swallowing, or shortness of breath. (This connection has only been established in animal studies.)
Always follow your healthcare provider’s instructions and immediately discuss any unusual or severe symptoms you experience. For detailed safety information and a full list of potential side effects, review the safety information for Zepbound® and Mounjaro®.
Who shouldn’t take tirzepatide?
Tirzepatide isn’t right for everyone. Like any medication, it’s important to weigh the risks and benefits, especially if you have certain health conditions or a family history of specific diseases. Before starting Mounjaro® or Zepbound®, your provider will review your medical background to help keep you safe.
Some conditions make tirzepatide unsafe to use altogether, while others may require close monitoring. Here’s what you need to know:
Don’t take tirzepatide (Mounjaro® or Zepbound®) if you or anyone in your family has had:
- Medullary thyroid carcinoma (MTC)
- Multiple endocrine neoplasia syndrome type 2 (MEN 2)
Also, avoid tirzepatide if you’ve previously had a serious allergic reaction to tirzepatide or any of its ingredients.
Before starting tirzepatide, inform your healthcare provider if you:
- Have had pancreatitis or gallbladder problems, including gallstones
- Have type 2 diabetes with diabetic retinopathy (eye problems)
- Experience mental health conditions, including depression or suicidal thoughts
You shouldn’t take tirzepatide if you are:
- Pregnant or planning to become pregnant
- Breastfeeding or planning to breastfeed
Tirzepatide: Getting the dose right
Finding the right tirzepatide dose is a process, and it won’t be the same for everyone. Whether you’re just starting out or adjusting your current dose, it’s all about finding an amount where the benefits outweigh the side effects. Everyone responds a little differently, which is why dose adjustments are made gradually, with close attention to how your body reacts. The goal isn’t to rush to the highest dose—it’s to find the dose that helps you lose weight in a steady, sustainable way while still feeling well. Many people don’t need the maximum dose.
That’s where your healthcare provider comes in. They’ll help guide the journey, monitor your progress, and adjust your dose based on your weight loss, comfort level, and any changes to your health. Keeping up with regular check-ins and being honest about how you’re feeling can make a big difference in reaching your goals safely. With the right support and a dose that fits your needs, tirzepatide can be a powerful tool in your long-term weight loss strategy.
Ozempic® and Mounjaro® are not FDA-approved to treat obesity or for weight loss.
