Mounjaro Protocol: Dosing, Injecting and Review Steps (October 2026)

01 · The core answer

The Mounjaro protocol at a glance

The protocol is a slow, stepwise climb on one weekly pen, and your prescriber, not a forum or a social media plan, decides how fast you move. Everyone starts Mounjaro on 2.5mg once a week. This starting dose is about letting your body adjust, not about weight loss itself.¹

Many people settle at a maintenance dose of 5mg, 10mg or 15mg. Higher is not automatically better, and your prescriber will guide the right pace.¹¹¹ For a deeper walk through each step, see our Mounjaro dosing protocol guide.

02 · Your next decision

Is this protocol right for you, and what next?

This protocol only applies to someone prescribed Mounjaro after a proper assessment. It is a prescription-only medicine, supplied after an online consultation reviewed by a GPhC-registered prescriber, and used alongside a reduced-calorie diet and increased physical activity.

If you are weighing up goals and timelines, our Mounjaro protocol for weight loss page covers expectations in more depth. When you are ready, the weight loss clinic explains how a free consultation works, and you can start from the Mounjaro pen page. Our GLP-1 weight loss protocol guide covers the ordering side.

03 · Dose ladder and pacing

Dose ladder and pacing

The ladder has six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg. After at least 4 weeks the dose increases to 5mg, and can then step up by 2.5mg at a minimum of 4-week intervals (7.5mg, 10mg, 12.5mg) up to a maximum of 15mg weekly, depending on how you respond and tolerate it.¹

Those intervals are minimums, not targets. Each KwikPen contains four weekly doses, so a pen is about a month of treatment at one strength.¹

That is why the jump between strengths is deliberate and why you should never swap or combine pens yourself.

04 · Injecting each week

Injecting each week

Mounjaro is injected under the skin (subcutaneously) once a week, on the same day each week, at any time of day, with or without food.¹ Licensed injection sites are the stomach area (at least 5cm from the belly button), the front of the thigh, or the back of the upper arm if someone else gives the injection. Rotate the site with each dose.¹³

You set the dose by turning the dose knob until the dose indicator shows the correct dose in the window.

Needles, a sharps bin and injection guidance come with every order. For step-by-step practice, read our Mounjaro injection technique guide and our Mounjaro preparation page.

05 · Missed doses and injection day

Missed doses and changing your injection day

The missed-dose rule is simple and time-limited. If you miss a dose, take it as soon as you can within 4 days (96 hours) of the scheduled time, then carry on with your usual day. If more than 4 days have passed, skip the missed dose entirely and take the next one on your normal day — never take two doses within 3 days of each other.¹

You can change your weekly injection day if needed, as long as at least 3 days (72 hours) have passed since your last dose.¹ People often move the day to fit travel or work, and the rule means you never double up.

There is no "best" time of day. Mounjaro works the same morning or evening, with or without food. What matters is the same day each week. Many people choose a weekend morning so early side effects fall on days off.¹³

06 · Storage and travel

Storage and travel

Keep Mounjaro pens in a fridge at 2–8°C and never freeze them. Once in use, a pen can be kept out of the fridge not above 30°C for up to 30 days — useful for short trips — after which it should be discarded. Keep the pen cap on to protect it from light, and never use a pen that has been frozen.¹³

You can fly with Mounjaro. Carry pens in hand luggage (hold luggage can fall below freezing), ideally in a cool bag with the prescription label or a copy of your prescription. For hot climates use an insulated pouch, and check destination rules for travelling with prescription injectables before you fly.¹³

Unopened pens should be kept in the fridge and keep until the expiry date printed on the box. If an unopened pen has been out of the fridge, check with the pharmacy before using it rather than relying on a remembered day limit — figures circulating online often come from other countries' labels.

07 · Results, review and stopping

Results, review and stopping

Weight loss on Mounjaro is gradual by design. The first weeks on 2.5mg are an adjustment phase and losses are usually modest; most measurable progress builds from 5mg onward, month by month. Think in months, not days, and judge progress by trend, not individual weigh-ins.⁴

For context, in the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone. These are trial averages — individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.² For someone starting at 100 kg, 20.9% is about 21 kg.

If you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, your prescriber will discuss whether continuing or stopping is right for you.⁴

Tirzepatide has a half-life of about five days, so after a final dose it takes roughly four to five weeks to clear the system. There is no way to speed this up, and nothing needs doing while it clears.¹

08 · Shortcuts to avoid

Shortcuts to avoid

Altering doses outside the licence means unknown dosing accuracy and no safety data.¹

Protocols shared in online communities describe individual choices, not licensed advice. Anyone offering to supply without a consultation or prescription should be avoided, and side effects can be reported through the Yellow Card scheme.¹⁹

09 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹