Mounjaro is a popular weight loss injection, helping people to lose an average 21.1% of their starting body weight after 72 weeks. It contains the active ingredient tirzepatide.
Mounjaro works similarly to two natural hunger hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), reducing hunger cues and helping people to eat less.
As it’s a prescription-only medication, Mounjaro should be taken at the dose prescribed for you by a healthcare professional. However, a trend known as Mounjaro microdosing has appeared as an alternative way to take the weight loss injection.
Microdosing isn’t recommended by healthcare professionals and there’s limited evidence about whether it works, yet some people are choosing to take smaller Mounjaro doses than recommended.
In this guide, we’ll explore what microdosing is, why people are doing it, what the risks vs potential benefits are, and summarise the evidence and guidance on this trend.
What does “microdosing Mounjaro” mean?
There’s no recognised medical definition of "microdosing” Mounjaro, but this term is used by people who are taking a smaller Mounjaro dose than the standard starting dose/lowest dose.
Typically, people who are microdosing Mounjaro choose to take a lower dose than 2.5 mg and continue taking this same smaller dose long-term. This often means using a single-dose Mounjaro KwikPen in a way that it’s not designed to be in order to administer a lower dose.
This is different to the standard way of taking Mounjaro where you begin with the starting dose and increase this every month (if you’re not experiencing side effects) through different set doses until you reach your maintenance dose.
Microdosing is also different to dose self-adjusting, where people take doses outside the standard prescribing guidance. In this situation, people tend to be taking higher doses rather than a “microdose”.
Mounjaro is prescribed at doses between 2.5mg and 15mg depending on your goals and how long you’ve been taking the medication. Learn more about the different doses available and how they’re typically increased in our Mounjaro dosing guide.
Why are people interested in microdosing Mouniaro?
Microdosing Mounjaro has emerged as a trend for several different reasons, including worries around side effects and treatment costs.
To minimise side effects
More than 10% of people taking Mounjaro experience the most common side effects like vomiting, nausea, diarrhoea, constipation, stomach pain, and/or tiredness. More serious side effects are much rarer, but can happen and include things like gallbladder problems or pancreatitis. Visit our guide to Mounjaro side effects for more information.
Side effects are more common in people taking higher doses, although gradually increasing the dose can give your body time to get used to the medication and counteract this to some degree.
By taking Mounjaro as a “microdose”, individuals may reduce their chances of experiencing side effects.
To reduce the cost
The cost of Mounjaro is another big reason why people are opting to microdose.
Mounjaro is an expensive medication, with a month’s supply of the Mounjaro 2.5mg starting dose costing £169.95 and the highest 15mg dose costing £314.95 per month.
Microdosing is a way for people to potentially get some of the benefits of Mounjaro for a cheaper price. At a lower dose, one pen will last longer meaning treatment is more cost effective (although this is not recommended as treatment is likely to be less effective).
As a weight maintenance strategy
Some people choose to switch from a standard Mounjaro dose to a “microdose” after reaching their target weight as a way to maintain the weight they’ve lost without losing more.
However, a standard Mounjaro maintenance dose or the new weight maintenance medication orforglipron are some of the recommended treatments for weight maintenance.
Can lower doses of Mounaro still work for weight loss?
People respond differently to Mounjaro and experience varying results. This is why the maintenance dose is adjusted based on your response and may be lower than the maximum 15mg dose.
Some people get excellent weight loss results at a lower maintenance dose of Mounjaro. Others don’t experience significant weight loss until they’ve been taking the maximum 15mg dose for some time.
In general, a higher dose is likely to lead to greater weight loss, but this needs to be balanced against side effects, cost, and your weight loss goals.
Your Mounjaro dosing schedule should always be adjusted by your prescriber - you should not adjust your Mounjaro dose yourself.
What does the evidence say about microdosing Mounjaro?
A recent editorial article published in the Lancet found no evidence that microdosing GLP-1s works for treating obesity/supporting weight loss.
There is limited evidence on the impacts of microdosing Mounjaro and doses below 2.5mg (the lowest licensed Mounjaro dose) have not been studied in clinical trials. This means we don’t fully understand the impact microdosing has on the body.
In clinical trials where the starting 2.5mg dose of Mounjaro were studied, patients only took this dose for 4 weeks before increasing it. During this time they lost, on average, just under 4% of their body weight.
People taking the lowest Mounjaro maintenance dose of 5mg for 72 weeks lost an average of 15% of their body weight in clinical trials. Although this is less than the 20.9% in the group taking the highest 15mg dose, it’s still a significant amount of weight loss.
The evidence suggests that lower doses of Mounjaro are typically less effective than higher doses, but they can still lead to impressive weight loss results. There’s not enough evidence to say whether this is true for microdosing below the studied 2.5mg starting dose.
Could lower doses be used for weight maintenance?
It’s possible lower Mounjaro doses could be used for weight maintenance in the future, but more research into taking Mounjaro long-term is needed. There is growing evidence that GLP-1 medications may need to be taken long-term to avoid weight regain.
If you’ve reached your target weight, you can discuss your options with your prescriber. They’ll be able to advise you what to do next, and whether switching to a GLP-1 tablet could be a good weight maintenance option for you instead.
What are the risks of microdosing Mounjaro?
Reducing your dose without medical advice comes with several risks including reduced effectiveness, potential weight regain, and problems from using the medication outside licensed guidance.
We don’t know whether Mounjaro doses lower than 2.5mg are effective for weight loss. You may be paying for the medication and experiencing the side effects without getting the weight loss benefits.
If you switch to a microdose that’s not effective, you’re risking regaining any weight that you’ve lost by previously taking Mounjaro at a prescribed higher dose.
To microdose Mounjaro, people have to use their single-dose pen in a way that it’s not designed to be used. This may mean injuring yourself with the needle, contaminating the medication, or potentially giving yourself an unknown dose. All of these things can put your health at risk.
You also risk losing some of the medication and not being able to use the pen which can cost you financially.
Should you reduce your Mounjaro dose?
The aim of taking Mounjaro is to support your weight loss journey and the best dose for you will balance cost with side effects and weight loss results. You should not adjust your medication dose without input from a healthcare professional.
If you need help with your Mounjaro dose, the Quick Meds team can help.
We offer an online weight loss clinic for personalised support on your weight loss journey. Our team of professional, attentive healthcare professionals are always here to offer advice and answer any question, big or small. Start your consultation today.
Sources
https://www.medicines.org.uk/emc/product/15481/smpc
https://www.thelancet.com/journals/landia/article/PIIS2213-8587(24)00376-0/fulltext
https://pmc.ncbi.nlm.nih.gov/articles/PMC12234836/
