Can Mounjaro Cause Raynaud's? What the UK Evidence Says (October 2026)

01 · The short answer

Is Raynaud's a Mounjaro side effect?

No. Raynaud's is not a listed side effect of Mounjaro in the UK Summary of Product Characteristics or the patient information leaflet.¹¹³

That does not make your symptom imaginary. People can develop colour changes in their fingers or toes for many reasons, and starting a new medicine is often just a coincidence in time. The useful question is not "does the box mention it?" but "what is causing this, and who should look at it?". A GP or prescriber is the right person to answer that.

02 · What to do

What should you do if you notice colour changes?

Tell a clinician rather than waiting to see whether it settles. If you are already taking Mounjaro through us, contact the prescribing team through your account, because ongoing monthly reviews and side-effect support are part of the service. If you buy treatment elsewhere, contact that prescriber or your GP.

It helps to bring specific details rather than a general worry. Note which fingers or toes are affected, what you were doing when it happened, how long it lasted, and when you started or last changed your dose. Mention every other medicine you take, including anything bought over the counter. A clear picture lets the clinician decide whether Mounjaro is even a plausible factor.

Do not stop treatment or alter your dose on your own because of this symptom. 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, and nothing speeds that up.¹ Stopping is therefore not a quick test of cause. It is a decision to make with your prescriber, not alone.

You can also report a suspected side effect yourself through the MHRA Yellow Card scheme.¹⁹ Reports from patients and clinicians are how regulators spot patterns that trials missed. Seek urgent medical help (111, or 999 in an emergency) if symptoms are severe, sudden or worsening.

03 · Next step

If you are still deciding about treatment

If you are researching Mounjaro and this symptom is one of your worries, raise it in the consultation. Our weight loss clinic explains how treatment works, and a prescriber can weigh your history before anything is supplied.

Related guide: Does Mounjaro Cause Spotting: Complete UK Guide 2026.

04 · What the label says

What the official product information says

The two documents that matter most are the Summary of Product Characteristics and the patient information leaflet. Together they list the side effects that have been identified for Mounjaro, grouped by how commonly they occur.¹¹³ Raynaud's does not appear in them as a side effect.

It is worth understanding what that does and does not mean. A side-effect list is built from clinical trials and from reports gathered after a medicine is on the market. It does not prove that no individual has ever had the symptom while taking it. It means the link is not established.

First, the symptom is real to the person experiencing it and deserves assessment. Second, the cause may be something other than the medicine. Treating those as separate questions avoids both false reassurance and false alarm.

The BNF entry for tirzepatide is another reference prescribers use for indications, dosing and safety information.¹¹ We encourage patients to read the patient leaflet that comes with every pen, because it is the version written for you, and it tells you which symptoms to report.

The Yellow Card scheme exists precisely for situations like this one.¹⁹ If you, or a clinician, suspect a medicine has caused a problem that is not on the label, a report adds to the evidence. You do not need to prove a link. You only need to describe what happened, what you were taking and when it started.

Online accounts of a symptom cannot control for other causes, and they are not evidence in the way a regulatory review is. When you read a page that says "many users report" a symptom, ask what the source actually is.

05 · How Mounjaro works

How Mounjaro works, and why that matters here

Mounjaro is the brand name for tirzepatide, a once-weekly injectable prescription medicine made by Eli Lilly. In the UK it is licensed for weight management in adults and for type 2 diabetes.¹ It comes as a pre-filled multi-dose pen (KwikPen) in six strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg.

Tirzepatide is the first treatment of its kind to activate two natural gut-hormone receptors at once: GIP and GLP-1. Together these help regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin.¹ In practice, most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.

It is about appetite, digestion and the body's response to insulin. It does not describe any direct action on the small blood vessels of the hands and feet, and the product information does not claim one.

This distinction matters when you talk to your prescriber. A good consultation will not ask "could Mounjaro do this?" in isolation. It will ask what else has changed: other medicines, health conditions, your environment, your general health. Mounjaro is one item on that list, and the label tells the clinician how seriously to weigh it.

If you want a refresher on how treatment is meant to be used, the key point is that it works alongside a reduced-calorie diet and increased physical activity, supervised by a prescriber who reviews you at regular intervals. That review is the natural place to bring any new symptom, whether or not it is a recognised side effect.

06 · Cold hands versus Raynaud's

Feeling cold versus a possible Raynaud's episode

Feeling generally colder and having distinct episodes in particular fingers or toes are different experiences, and a clinician will want to tell them apart.

Start with whether the sensation is general or specific. Do you simply feel the cold more than you used to, all over? Or do particular digits change in appearance, with an obvious difference in colour from the surrounding skin? These are separate observations and may have separate explanations. Writing down which applies to you is the most useful thing you can bring to an appointment.

Next, think about timing and triggers. Did it begin around the time you started a new medicine, changed dose, changed your eating, or changed your environment? Does it happen in a particular setting, such as handling cold items or moving between rooms with different temperatures? Does it happen at rest? Clinicians use this kind of pattern to decide what to examine next.

Then consider how it resolves. Note whether the change settles by itself, how long it takes, and whether there is discomfort, numbness or anything else alongside it. Photographs taken during an episode can be extremely helpful, because the change may be gone by the time you are seen.

Because many unrelated things can make hands and feet feel or look different, it would be unwise to attribute this to Mounjaro without that assessment. Equally, it would be unwise to dismiss it. The sensible middle path is to record the details, tell your prescriber, and let them decide what is needed.

If anything about the symptom is severe, sudden or getting worse, do not wait for a routine review. Contact your GP, call 111, or call 999 in an emergency.

07 · Weight loss and the body

Weight loss on treatment: what the trial actually showed

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.² These are trial averages. Individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.

At 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight. Half of participants on 10mg and 57% on 15mg lost at least 20% of their body weight.²

As a worked example, for someone starting at 100 kg, 20.9% is about 21 kg. That is simple arithmetic of the trial average, not a prediction of your own result.

Treatment is meant to produce substantial weight change over a long period, and a prescriber reviewing you will want to know about any symptom that appears during that time. Whether a new symptom is related to the medicine, to the changes in your body, or to something unrelated is precisely what a clinician sorts out.

If you are eating very little, struggling to keep up with food or drink, or feeling unwell in general, tell your prescriber. Your treatment is supposed to support a reduced-calorie diet, not an extreme one, and the prescribing team can help you adjust.

Finally, keep your expectations realistic.

08 · Other medicines and review

Other medicines, conditions and why a full review matters

If you take something bought online or from a shop, say so, including products marketed for weight loss with dramatic weight-loss claims. Dosing of such products is not standardised, and they come with no clinical oversight.

Bring the information in a way that is easy to read: a written list, or the boxes themselves. A pharmacist can often review a medicine list quickly and tell you whether anything warrants a closer look. Your GP can go further, including examining you and arranging tests where appropriate.

Tell the prescriber about your wider health too. Conditions you already have, and any new symptoms alongside the colour changes, help build the full picture.

For example, the medicine can reduce absorption of oral contraceptives because stomach emptying slows, and the MHRA has issued guidance on contraception with these medicines.⁷ The SmPC advises switching to a non-oral method, or adding a barrier method (such as condoms), for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase.¹ Where you take insulin or sulfonylureas, doses may need adjusting because of the risk of low blood sugar.

Repeat orders with us re-check suitability, and there is no auto-shipping. If your circumstances change, including a new symptom, that is exactly what the check is for. Please use it.

If you are already seeing a specialist or have a diagnosis, tell your Mounjaro prescriber about it and tell the specialist you are taking tirzepatide. Joined-up information is the best protection you have.

09 · Next steps and safety

A practical plan for the next few days

If you have noticed colour changes in your fingers or toes since starting Mounjaro, a calm, structured plan works better than searching for causes online.

First, keep taking your treatment as prescribed unless a clinician tells you otherwise. Off-label changes to dosing carry their own risks and are not something we advise.

Second, record what happens. A short diary of when episodes occur, what you were doing, and how long they last gives a clinician much more to work with than a general impression. Take photographs during an episode where you can.

Third, contact a clinician. If you buy from us, use the account portal chat, email support@everydaymeds.co.uk or phone 0333 207 0413 during support hours, Monday to Friday, 9am to 5pm. Your prescribing team can review your dose history and advise on whether you need to see your GP in person. If it is outside those hours and you are worried, use NHS 111.

Fourth, consider a Yellow Card report through the MHRA scheme.¹⁹ You can submit it yourself, and it does not replace seeing a clinician.

Fifth, think carefully before stopping. Because tirzepatide takes around four to five weeks to clear, stopping will not give you a quick answer, and it may undo progress you have made.¹ If your prescriber and you decide a pause or dose change is sensible, that is a joint clinical decision.

Finally, store your pens correctly and use them as the leaflet instructs. Once in use, a pen can be kept out of the fridge at a temperature not above 30°C for up to 30 days after first use, and must then be thrown away.

If your symptoms are severe, sudden or worsening, do not follow this plan; seek urgent help instead. Call 111 or, in an emergency, 999.

10 · NHS, private and ordering

NHS access, private treatment and how ordering works

Some readers arrive here because they are weighing up whether to start treatment, and a possible symptom is giving them pause. It is a reasonable thing to raise, and where you get treatment affects who you can raise it with.

Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition, and the NHS 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 is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting. The NHS medicine guide is a good neutral reference.⁵

If you choose private treatment, the route matters. EverydayMeds is a GPhC-registered UK online pharmacy (registration 9012878), and Mounjaro is supplied only after an online consultation reviewed by a GPhC-registered prescriber. Our supply is official LillyDirect supply, direct from Eli Lilly's UK distribution, with genuine KwikPens and all six doses stocked, currently in stock.

Ordering works in simple steps. You complete a free online consultation, a short health questionnaire with no charge and no obligation. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full. Our registered pharmacy dispenses it, with same-day dispatch when ordered by 3pm, and delivery is free next-day tracked in temperature-controlled packaging.

Aftercare is part of the service: ongoing monthly reviews, dose titration, follow-up assessments and side-effect support from the prescribing team. If you want to track your journey, the free GLPTrackr app is available for iOS and Android. Please disclose all symptoms and medicines in your consultation, so that the prescriber has what they need.

Whichever route you take, treat any new symptom as worth reporting, and keep treatment alongside a reduced-calorie diet and increased physical activity. Mounjaro is a prescription-only medicine, results vary, and this page is information, not a substitute for medical advice.

11 · Reading symptom claims online

How to judge claims about Mounjaro side effects online

Questions like this one attract confident answers of very uneven quality. A few habits help you separate reliable information from noise.

Check what the source is. The strongest sources are the Summary of Product Characteristics, the patient information leaflet, the BNF and regulators such as the MHRA.¹¹¹¹³ They are written for clinicians and patients, and updated as evidence changes. Be more cautious with a page that says only that people report something, without saying where the information comes from.

Watch for causal language that outruns the evidence. "Mounjaro can make you colder" is a different claim from "Mounjaro causes Raynaud's", and both are different from "people feel colder when they lose weight". A page that blends them is telling a story, not citing evidence.

Be wary of anyone selling a remedy. Supplements marketed as natural alternatives often come with dramatic weight-loss claims, low-cost availability and no clinical oversight. Their dosing is not standardised, and nothing about their cheapness makes them safe or effective. Do not start a supplement to treat a symptom you have not had assessed.

Be careful with where you buy. The MHRA issues counterfeit medicine alerts, and genuine treatment is supplied only after a consultation and prescription.⁷ Anyone offering to supply without a consultation or prescription should be avoided. You can verify a pharmacy on the GPhC register.

Finally, remember that reporting is how knowledge grows. If you think a medicine has caused a problem, the Yellow Card scheme is where that suspicion becomes data.¹⁹ If many credible reports accumulate, regulators can act, and product information can change. Until then, the honest statement stands: Raynaud's is not a listed side effect of Mounjaro.

Our guides on tremors, breathlessness, sleepless nights and blood clots cover other symptoms.

12 · 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