Mounjaro KwikPen 15mg (Lilly) UK Guide (October 2026)

01 · Price

What the Mounjaro 15mg KwikPen costs

A 15mg Mounjaro KwikPen costs £329.99 per month at the standard price. A new customer's first order is £40 less at any dose, with code FIRST40, so a first 15mg order is £289.99. Every later order is £25 off the standard price (code DOSE25). For live figures across other strengths, see our Lilly Mounjaro price guide or the authentic Eli Lilly 15mg price page.

For planning, the first four pens (2.5mg, 5mg, 7.5mg, 10mg) cost £959.96 at standard prices. A first year costs £2,711.88 if you settle at 5mg, up to £3,599.88 at 15mg. Those totals are before discounts.

02 · Suitability

Who 15mg is for

Everyone starts on 2.5mg once a week. After at least 4 weeks the dose rises to 5mg, then by 2.5mg steps at minimum 4-week intervals up to 15mg, depending on response and tolerance.¹ Many people settle at 5mg, 10mg or 15mg. Higher is not automatically better, and your prescriber guides the pace.¹

Mounjaro is licensed for adults with a BMI of 30 or above, or 27 to 30 with a weight-related condition, alongside a reduced-calorie diet and more activity.¹ Our free consultation is reviewed by a GPhC-registered prescriber; start your free consultation.

03 · Ordering

How ordering works

• Complete the free online consultation, with no charge or obligation.
• A GPhC-registered prescriber reviews it. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.
• We dispense and dispatch the same day when ordered by 3pm, with free next-day tracked delivery in temperature-controlled packaging. Needles, a sharps bin and injection guidance are included.

Repeat orders re-check suitability, and there is no auto-shipping. Compare with our Lilly Mounjaro pen overview.

04 · 15mg results

What happens on 15mg

In SURMOUNT-1, 2,539 adults on tirzepatide alongside diet and exercise lost on average 15% of body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, against 3.1% with lifestyle changes alone.² For someone starting at 100 kg, 20.9% is about 21 kg. These are trial averages, and individual results vary.²

At 72 weeks, 91% of those on 15mg had lost at least 5% of body weight, and 57% lost at least 20%.² Read more on what the 15mg pen is used for.

05 · Storage and travel

Storage, 30 days (not above 30°C) and flying

Keep pens in a fridge at 2–8°C and never freeze them. Once in use, a pen can stay out of the fridge not above 30°C for up to 30 days, then it should be discarded.¹³ Keep the cap on to protect it from light.

You can fly with Mounjaro. Carry pens in hand luggage, as hold luggage can fall below freezing, ideally in a cool bag with the prescription label or a copy of your prescription. Check destination rules first. Unopened pens keep until the printed expiry date; if one has been out of the fridge, check with the pharmacy before using it.¹³ Our genuine KwikPen needles page covers supplies.

06 · Weekly dosing rules

Injecting weekly

Inject under the skin once a week on the same day, at any time, with or without food. Sites are the stomach (at least 5cm from the navel), the front of the thigh, or the back of the upper arm if someone else injects. Rotate sites each dose.¹³

If you miss a dose, take it within 4 days (96 hours) of schedule; after that, skip it. Never take two doses within 3 days of each other. You can change your injection day if at least 3 days have passed since the last dose.¹³

07 · NHS and private

NHS or private access

Mounjaro is available on the NHS, but access is phased over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition, and the primary-care rollout began in June 2025 with the highest-need groups first, initially BMI 40+ with four or more qualifying conditions.⁴⁶ Full rollout will take years, so many people who meet the licensed criteria choose regulated private treatment.