GLP-1 Training: Exercise, Marathons and Clinician Courses (October 2026)

01 · Start here

What does GLP-1 training actually mean?

It means different things depending on who is asking, and the right next step depends on which group you are in.

02 · For patients

Is training part of GLP-1 treatment?

Yes. Mounjaro (tirzepatide) is a prescription-only medicine used alongside a reduced-calorie diet and increased physical activity¹. Individual results vary, and the trial results quoted for the medicine were achieved with diet and exercise, not without them².

The medicine works by activating GIP and GLP-1 receptors. These help regulate appetite, slow how quickly the stomach empties and improve the way the body responds to insulin¹. In practice, most people feel fuller sooner and less hungry between meals. That can make eating enough around training something to think about deliberately, and your prescriber is the right person to talk it through with.

If you want to understand whether the hype is justified, our piece asking is GLP-1 a con looks at the hype versus the evidence.

03 · What to do next

What should you do next?

If you are not yet on treatment and want to know whether it suits you, start with a free online consultation. It is reviewed by a GPhC-registered prescriber, with no charge and no obligation. You can see the Mounjaro pen and current prices or read more on our weight loss clinic page.

04 · Planning your week around injections

Planning training around your weekly injection

The simplest way to combine training with treatment is to treat your injection day as a fixed point and build the week around it. Mounjaro is injected under the skin weekly, on the same day each week, at any time of day, with or without food¹.

There is no "best" time of day. Mounjaro works the same morning or evening¹. What matters is picking a day and time you will remember. Many people choose a weekend morning so early side effects fall on days off¹. For a trainer or runner, that has a useful knock-on effect: you can keep your key sessions away from the days when you tend to feel flattest.

Why this matters: mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects, and they usually settle¹. Keep a simple note of how you feel after each dose. Your pattern will become clear within the first few weeks, and it will tell you better than any generic plan when to schedule harder sessions.

Practical points:

• Rotate the injection site with each dose. Licensed 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.
• If you need to move your injection day, you can, as long as at least 3 days (72 hours) have passed since your last dose.

If you want to log injections alongside training sessions, our free companion app GLPTrackr is available for iOS and Android.

05 · Marathon and endurance events

GLP-1 marathon training: what to plan for

You can train for endurance events while on a GLP-1 medicine, but you should involve your prescriber, because appetite changes and early-dose side effects affect fuelling and recovery. Our dedicated guide to Mounjaro and marathon training goes into more detail.

Dose changes and big training blocks do not mix well by accident. The dose ladder starts at 2.5mg and rises in steps, with at least four weeks between increases¹. Each step can bring a fresh run of early effects. If you are still titrating, avoid scheduling your biggest sessions or race day for the days just after a dose increase, and discuss timing with your prescriber.

Race-weekend logistics are where most runners stumble. A few facts help:

• In-use pens can be kept out of the fridge at a temperature not above 30°C for up to 30 days after first use, after which the pen must be thrown away¹. Most training camps and event trips therefore need no special arrangements.
• Keep pens at 2–8°C in the fridge until first use, never freeze them, and keep the cap on to protect from light¹.
• You can fly with Mounjaro. Carry pens in hand luggage because hold luggage can fall below freezing, ideally in a cool bag with the prescription label or a copy of your prescription¹. For hot climates use an insulated pouch.
• Check destination rules for travelling with prescription injectables before you fly.

If your injection day falls on a travel day and you miss it, take the dose as soon as you can within 4 days (96 hours) of the scheduled time. If more than 4 days have passed, skip the missed dose and take the next one on your normal day. Never take two doses within 3 days of each other¹.

06 · Realistic expectations

What training can and cannot change

Treatment results build gradually, and exercise does not turn that into a fast process. 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 month¹.

The trial evidence frames what is realistic. In SURMOUNT-1, 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 alone². These are trial averages and individual results vary. Trial averages do not predict your own result.

Early loss includes water weight, so the trend over weeks matters more than any single weigh-in¹. Training can make the scale confusing, since glycogen and fluid shift with hard sessions. Judge progress by trend, not individual weigh-ins, and use other measures you find motivating, such as how your runs or lifts feel.

Treatment response is reviewed by your prescriber. 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 you¹.

07 · Injection training for new patients

GLP-1 injection training: learning to use the pen

The Mounjaro KwikPen is set by turning the dose knob until the dose indicator shows the correct dose in the window. Follow the pen's instructions and the patient information leaflet for the injection steps themselves.

A word on shortcuts. Altering doses outside the licence means unknown dosing accuracy and no safety data, which is a poor trade for anyone training hard.

08 · Courses for clinicians

GLP-1 training courses for healthcare and fitness professionals

Professional GLP-1 training is a separate area from patient exercise advice.

When choosing, check what a course covers rather than its title. Our overview of the GLP-1 training course options explains how to compare them, and the list of free online GLP-1 training shows what is available without paying.

Fitness professionals have a different role. You can support a client's training, routine and motivation, but you should not advise on doses, adjust medication or interpret side effects. Those belong with the prescriber. A client who mentions a new symptom should be encouraged to talk to their prescriber, and they can also report suspected side effects through the Yellow Card scheme¹⁹. If a client describes severe, persistent stomach pain, chest pain, swelling of the face or throat, or difficulty breathing, they should get medical help straight away.

Clinicians interested in the laboratory side may also see our explainer on the GLP-1 assay, which is a different topic from prescribing education.

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