What is multiple sclerosis?
Multiple sclerosis is a chronic autoimmune condition affecting the central nervous system. The immune system mistakenly attacks the protective myelin sheath surrounding nerve fibres in the brain and spinal cord, causing inflammation and damage.
This damage disrupts the normal flow of electrical signals between the brain and body, leading to a wide range of symptoms, including fatigue, mobility problems, vision issues, numbness, and cognitive changes.
Relapsing-remitting MS is the most common form, affecting about 85% of people initially diagnosed.2 Most people with MS are diagnosed between ages 20 and 50, and women are approximately 2.5 times more likely to develop the condition than men.2
Maintaining a healthy weight is important for MS patients because excess weight can worsen symptoms, reduce mobility, and accelerate disease progression.
The obesity-MS connection: why weight loss matters
The relationship between obesity and MS is well-established. Research consistently shows that carrying excess weight worsens MS outcomes in several ways.
A 2024 Swedish study followed 3,249 MS patients for an average of 10.6 years and found that obesity was associated with:3
- 43% higher risk of reaching EDSS 3 (moderate disability)
- 40% higher risk of reaching EDSS 4 (significant walking impairment)
- More rapid cognitive decline
- Higher MRI activity showing new brain lesions
A German study of 1,066 MS patients found even more striking results: obese patients reached disability milestones nearly 50% faster than those with normal weight.4
Specifically, obese MS patients reached EDSS 3 in an average of 0.99 years compared to 1.46 years for non-obese patients.
The mechanisms linking obesity and MS progression involve chronic inflammation. Fat tissue, particularly visceral fat surrounding internal organs, secretes inflammatory proteins that may exacerbate the neuroinflammation already present in MS.
Weight loss is now considered a modifiable risk factor for MS progression. Unlike genetic factors or environmental exposures that are difficult to change, weight is something that can be addressed with proper support.
Emerging research on GLP-1 medications and MS
Interestingly, emerging evidence suggests that GLP-1 medications may have neuroprotective benefits beyond weight loss.
A 2025 study presented at the American Academy of Neurology conference analysed data from 7,046 MS patients taking GLP-1 agonists, compared with matched controls, over five years.1 The findings were significant:
- Those not taking GLP-1 medications showed significantly more MS disease progression
- Higher risk of brainstem dysfunction (4.36% risk difference)
- Higher risk of cerebellar dysfunction (4.54% risk difference)
- Higher risk of bowel and bladder dysfunction (4.98% risk difference)
Research from Johns Hopkins University found that GLP-1 receptor agonists delayed disease onset and reduced severity in animal models of MS.5 The medications appear to reduce neuroinflammation and may protect nerve cells from damage.
Real-world safety data is also reassuring. A Massachusetts General Hospital study of 49 patients with MS taking GLP-1 medications found tolerability comparable to that in the general population, with an average weight loss of 0.47 kg per month.6
A Beth Israel study of 60 MS patients reported a 3.7% mean reduction in BMI, increased vitamin D levels (which are beneficial for MS), and no change in disability scores.7
It’s important to note that this research is still emerging. A clinical trial at Northwestern University (NCT07207148) is currently investigating GLP-1 agonists specifically in patients with MS who are taking ocrelizumab.8
Still, the early evidence suggests these medications may be particularly beneficial for people with MS.
How does Mounjaro work?
Mounjaro (tirzepatide) is a dual-action weight-loss injection that mimics two hormones: GLP-1 and GIP. These hormones signal to the hypothalamus, the brain’s appetite control centre, to reduce hunger and food-seeking behaviour.
By lowering hunger and our desire to eat, Mounjaro helps create a calorie deficit, which is when we consume fewer calories than our body needs. This prompts the body to use stored fat for energy, resulting in weight loss.
Mounjaro also slows gastric emptying, meaning food stays in the stomach longer. This helps you feel full faster and stay satisfied for longer after eating.
Clinical trials show Mounjaro leads to an average weight loss of around 20-26% after one year, making it one of the most effective weight-loss medications currently available.9
For patients living with MS, the anti-inflammatory effects of GLP-1 medications may confer benefits beyond weight loss, although further research is needed to elucidate these mechanisms.
Drug interactions with MS medications
No direct pharmacokinetic interactions have been identified between tirzepatide (Mounjaro) and common MS disease-modifying therapies (DMTs).10
Tirzepatide is metabolised through proteolytic cleavage rather than hepatic cytochrome P450 pathways. This means it doesn’t compete with the liver enzymes that metabolise many other medications, reducing the likelihood of drug interactions.
Common MS medications that have been checked for interactions include:
Injectable DMTs: Interferons (Avonex, Rebif, Betaferon), glatiramer acetate (Copaxone)
Oral DMTs: Fingolimod (Gilenya), dimethyl fumarate (Tecfidera), teriflunomide (Aubagio), siponimod (Mayzent), cladribine (Mavenclad)
Infusion DMTs: Natalizumab (Tysabri), ocrelizumab (Ocrevus), alemtuzumab (Lemtrada)
While there are no direct interactions, some practical considerations apply:
- Immunosuppressive DMTs: Maintaining adequate nutrition and hydration is important when taking immunosuppressive medications. If Mounjaro causes significant nausea or reduced appetite, work with your healthcare team to ensure you’re still getting adequate nutrition.
- Corticosteroid pulses: If you need high-dose steroids for an MS relapse, these may temporarily offset Mounjaro’s glucose-lowering effects. Your blood sugar may be higher than usual during steroid treatment.
- Oral contraceptives: As with all patients taking Mounjaro, absorption of oral medications may be affected. This is a standard consideration, not specific to MS.
Always inform your neurologist that you’re taking or planning to take Mounjaro. While drug interactions aren’t a concern, coordinated care between your MS team and prescriber ensures the best outcomes.
Practical considerations for MS patients
Taking Mounjaro with MS requires some additional planning compared to the general population. Here’s what to consider:
Coordinate with your MS team
Before starting Mounjaro, consult your neurologist. While they may not be the prescribing clinician, they should be aware of all medications you’re taking. Your MS nurse can also be a valuable resource for monitoring how you’re responding.
Managing overlapping symptoms
Some Mounjaro side effects can overlap with MS symptoms, which may make it harder to tell what’s causing what:
- Fatigue: Both MS and Mounjaro can cause tiredness. If fatigue worsens significantly after starting Mounjaro, it may be worth reducing the dose or adjusting the titration schedule.
- GI issues: Nausea and constipation are common on Mounjaro. Some MS medications also affect the gut. Keep a symptom diary to help identify patterns.
- Dizziness: This can occur with both Mounjaro (especially if eating too little) and MS. Stay well-hydrated and eat regular meals.
Nutrition considerations
Eating enough protein is crucial when taking Mounjaro, and this is even more important for MS patients:
- Protein: Aim for 30-40g of protein at each meal to preserve muscle mass. Muscle strength is particularly important for mobility in MS.
- Vitamin D: Many MS patients supplement vitamin D. Studies show vitamin D levels may actually improve on GLP-1 medications.7 Continue your vitamin D supplementation as directed by your neurologist.
- Hydration: Staying well-hydrated helps with both Mounjaro side effects and bladder health in MS. Aim for 2 litres of water daily unless advised otherwise.
Monitoring your progress
Keep track of both your weight loss and any changes in MS symptoms. While weight loss generally improves MS outcomes, rapid weight loss should be monitored. Aim for steady, sustainable weight loss of 0.5-1kg per week.
Exercise on Mounjaro with MS
Exercise is now strongly encouraged for people with MS, representing a significant shift from earlier guidance recommending rest.
Current guidelines recommend at least 150 minutes of moderate-intensity aerobic activity per week, plus strength training twice per week.11
When combining Mounjaro with MS, exercise becomes even more important for preserving muscle mass during weight loss. However, some adaptations may be needed:
Heat sensitivity
About 80% of MS patients experience heat sensitivity, where symptoms temporarily worsen when body temperature rises.2 To manage this:
- Exercise in air-conditioned spaces or cooler times of day
- Use cooling vests or cold packs
- Keep cold water available during workouts
- Consider swimming or water-based exercise
Fatigue
MS fatigue is different from normal tiredness and affects about 80% of patients.2 Shorter, more frequent exercise sessions often work better than long workouts:
- Try 10-15 minute sessions multiple times per day
- Exercise during your peak energy times
- Rest as needed between exercises
- Don’t push through extreme fatigue
Adapted exercises
Depending on your mobility level, you may need to adapt exercises:
- Seated exercises if balance is affected
- Resistance bands instead of free weights
- Recumbent bikes instead of upright cycles
- Chair yoga or gentle stretching
A physiotherapy evaluation before starting a new exercise programme is highly recommended. A physio can assess your current abilities and design a programme that’s safe and effective for your specific situation.
Strength training
Strength training is particularly important when taking Mounjaro because it helps preserve muscle mass during weight loss.
For patients living with MS, maintaining muscle strength also supports mobility and independence. Aim for at least two strength-training sessions per week, targeting major muscle groups.
Comparison: MS patients vs general population on Mounjaro
| Consideration |
General population |
MS patients |
| Drug interactions |
Few significant interactions |
No direct interactions with DMTs; coordinate with neurologist |
| Exercise approach |
Standard recommendations |
Adapted for fatigue and mobility; exercise in cool environments |
| Side effect overlap |
N/A |
Fatigue and GI issues may overlap with MS symptoms |
| Medical coordination |
GP and prescriber |
Neurologist, MS nurse, and prescriber coordination recommended |
| Protein needs |
1.2-1.6g per kg body weight |
Same or higher; muscle preservation is especially important for mobility |
| Vitamin D |
Standard supplementation advice |
Often already supplementing; levels may improve on Mounjaro |
| Potential additional benefits |
Weight loss and metabolic improvements |
Emerging evidence of possible neuroprotective effects |
Frequently asked questions
Can Mounjaro interact with my MS medications?
No direct drug interactions have been identified between tirzepatide (Mounjaro) and common MS disease-modifying therapies.
Mounjaro is metabolised differently from most medications, reducing the risk of interactions. However, always inform your neurologist about all medications you’re taking.
Should I tell my neurologist I’m taking Mounjaro?
Yes, definitely. While your neurologist may not be prescribing Mounjaro, they should know about all medications and supplements you’re taking.
This ensures coordinated care and helps them monitor for any changes in your MS. Your MS nurse can also be informed.
Will weight loss help my MS symptoms?
Research suggests yes. Studies show obesity is associated with faster MS progression, more disability, and increased brain lesion activity.
Losing weight reduces inflammation and may slow disease progression. The Swedish study found obese MS patients had a 43% higher risk of reaching significant disability compared to those with normal weight.3
Can Mounjaro make my MS worse?
Current evidence suggests the opposite. The 2025 AAN study found MS patients on GLP-1 medications had less disease progression than matched controls.1
While research is ongoing, there’s no evidence that Mounjaro worsens MS, and emerging data suggests it may be beneficial.
What if I experience fatigue? Is it MS or Mounjaro?
This can be tricky to distinguish. Mounjaro-related fatigue typically occurs in the early weeks and improves as your body adjusts.
MS fatigue tends to be more persistent and may worsen with heat or activity. Keep a symptom diary, noting when fatigue occurs and any patterns.
If fatigue significantly worsens after starting Mounjaro and doesn’t improve after 4-6 weeks, discuss with your prescriber.
Can I exercise while on Mounjaro with MS?
Absolutely. Exercise is strongly recommended for MS and helps preserve muscle during weight loss on Mounjaro.
Adaptations may be necessary to address heat sensitivity, fatigue, and mobility limitations. A physiotherapy assessment can help design a safe, effective programme for your situation.
What about vitamin D levels?
Many MS patients already supplement vitamin D, which is important for immune function. Studies indicate that GLP-1 medications may improve vitamin D levels.7 Continue your vitamin D supplementation as directed by your neurologist and have levels monitored regularly.
How much weight can I expect to lose?
Clinical trials show Mounjaro leads to average weight loss of 20-26% after one year.9 Individual results vary based on starting weight, dose, diet, and activity level. Studies in MS patients specifically show safe weight loss with no negative impact on disability scores.6,7
Should I come off Mounjaro before steroid treatment for a relapse?
No, you don’t need to stop Mounjaro for steroid pulses. However, be aware that high-dose corticosteroids temporarily raise blood sugar levels, which may offset some of Mounjaro’s glucose-lowering effects.
Your blood sugar may be higher than usual during steroid treatment. This is temporary and will return to normal after the steroids finish.
Is there any research specifically on Mounjaro and MS?
Most research to date has studied GLP-1 medications as a class rather than Mounjaro specifically. However, since Mounjaro works through the GLP-1 pathway (plus GIP), the findings are likely applicable.
A clinical trial specifically examining GLP-1 agonists in MS patients is currently underway at Northwestern University.8
Take home message
You can safely take Mounjaro if you have multiple sclerosis. There are no direct drug interactions with MS medications, and emerging research suggests GLP-1 medications may offer neuroprotective benefits beyond weight loss.
Given that obesity worsens MS outcomes and accelerates disease progression, weight management is particularly important for people living with MS. The evidence linking obesity to faster disability progression is strong and consistent across multiple studies.
While research on GLP-1 medications and MS is still emerging, the early findings are encouraging. For MS patients with obesity, Mounjaro offers a way to address a modifiable risk factor that may genuinely improve long-term outcomes.
Second Nature's Mounjaro and Wegovy programmes
Second Nature provides Mounjaro or Wegovy as part of our Mounjaro and Wegovy weight-loss programmes.
Why choose Second Nature over other medication providers, assuming you're eligible?
Because peace of mind matters.
We've had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.
Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro and Wegovy) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.
At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes. We're here to support that change every step of the way.
With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we're the UK's most trusted weight-loss programme.
We hope to offer you something invaluable: peace of mind, and the support you need to take that first step.
References
- Ali K, et al. (2025). GLP-1 Medications Associated with Reduced MS Relapse Risk. Presented at American Academy of Neurology Annual Meeting 2025.
- MS Society UK. (2024). What is MS?
- Hedström AK, et al. (2024). Obesity Affects Disease Activity and Progression, Cognitive Functioning, and Quality of Life in People With Multiple Sclerosis. Neurology Neuroimmunology & Neuroinflammation, 11(6), e200334.
- Lutfullin I, et al. (2023). Association of obesity with disease outcome in multiple sclerosis. Journal of Neurology, Neurosurgery & Psychiatry, 94:57-61.
- Yun SP, et al. (2018). Block of A1 astrocyte conversion by microglia is neuroprotective in models of Parkinson’s disease. Nature Medicine, 24(7), 931-938.
- Udawatta M, et al. (2025). Multiple sclerosis patients taking glucagon-like peptide-1 receptor (GLP-1) agonists: a single-institution retrospective cohort study of tolerability and weight loss. Neurological Sciences, 46(1), 343-349.
- Balshi A, et al. (2024). Glucagon-like peptide-1 agonist safety and efficacy in a multiple sclerosis cohort. Multiple Sclerosis and Related Disorders, 93, 106229.
- ClinicalTrials.gov. (2024). People With Multiple Sclerosis Treated With Ocrelizumab. Northwestern University.
- Jastreboff AM, et al. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine, 387(3), 205-216.
- National Institute for Health and Care Excellence. (2025). Tirzepatide for managing overweight and obesity.
- Motl RW, et al. (2017). Exercise in patients with multiple sclerosis. Lancet Neurology, 16(10), 848-856.
