How RA and weight are connected
The relationship between RA and body weight is bidirectional. Excess weight increases the load on already inflamed joints, and the additional fat tissue itself produces inflammatory molecules that can worsen RA symptoms.
At the same time, RA makes it harder to stay active. Joint pain and fatigue limit movement, and some RA medications, particularly corticosteroids, can contribute to weight gain.
Research shows that people with RA who carry excess weight are less likely to achieve disease remission. Reducing body weight can improve disease activity scores, inflammatory markers, and physical function.1
While Mounjaro isn’t an RA treatment, supporting significant weight loss may help reduce the inflammatory and mechanical burden that excess weight places on joints.
How Mounjaro works
Mounjaro contains the drug tirzepatide, which mimics two gut hormones: GLP-1 and GIP. These hormones are released naturally after eating and help regulate appetite and blood sugar levels.
By mimicking both hormones, Mounjaro reduces hunger and helps you feel full for longer. Clinical trials have shown it supports up to a 26% weight loss after two years.2
The medication is given as a once-a-week injection. The dose is gradually increased over several weeks to reduce the likelihood of side effects, particularly nausea.
What does the research say about Mounjaro and RA?
The evidence specifically looking at Mounjaro in people with RA is limited, but what exists is promising.
A 2024 conference abstract presented at the American College of Rheumatology examined 152 people with RA who were prescribed anti-obesity medications, primarily semaglutide and tirzepatide.1
The researchers found reductions in ESR and CRP (both markers of inflammation in the blood) alongside improvements in pain scores and cardiovascular risk factors.
It’s worth noting that this was a retrospective study presented as a conference abstract, not a full peer-reviewed paper.
The results are encouraging, but larger, controlled trials are needed before drawing firm conclusions about how Mounjaro specifically affects RA.
Potential benefits beyond weight loss
There are a few reasons why weight loss medications might help people with RA beyond simply reducing body weight.
Fat tissue, particularly around the abdomen, produces inflammatory proteins called cytokines. Reducing fat mass lowers the production of these molecules, which may ease systemic inflammation.
Less body weight also means less mechanical stress on weight-bearing joints like the knees and hips. For someone with RA, this could mean less pain during daily activities.
Mounjaro also improves blood sugar regulation and cardiovascular risk markers. People with RA have an elevated risk of heart disease, so these metabolic improvements could be particularly relevant.1
Foods that support joint health on Mounjaro
What you eat won’t cure RA, but certain dietary patterns are associated with lower levels of inflammation.
We recommend eating a diet based on whole foods that minimises the consumption of ultra-processed foods.
Consuming foods with more potent anti-inflammatory properties may help to manage the higher inflammation levels seen in RA.
Prioritise protein to protect muscle
RA can cause a form of muscle wasting called rheumatoid cachexia, where chronic inflammation breaks down muscle tissue. This happens even if body weight stays the same or increases, because muscle is replaced by fat.
When you’re also losing weight on Mounjaro, it’s essential to protect muscle mass. Rapid weight loss can lead to a greater loss in lean tissues.
Include a source of protein the size of the palm of your hand at each meal: chicken, fish, eggs, Greek yoghurt, tofu, or beans and lentils all work well.
Omega-3-rich foods for inflammation
Omega-3 fatty acids have the strongest dietary evidence for reducing RA symptoms. A 2024 meta-analysis of 18 trials found that omega-3 supplementation (EPA and DHA) reduced tender joint count in people with RA.3
You can get omega-3s from oily fish like salmon, mackerel, sardines, and trout. Aim for two portions a week.
Plant sources such as walnuts, flaxseeds, and chia seeds provide a different form of omega-3 (ALA), though conversion to the marine forms (EPA and DHA) is limited.
Vegetables and fibre
Colourful vegetables provide antioxidants and polyphenols that may help manage inflammation. Leafy greens, peppers, broccoli, and beetroot are all good choices.
Fibre from vegetables and complex carbohydrates also supports gut health, which is relevant to RA. Research increasingly links gut bacteria composition to autoimmune conditions, and a diverse, fibre-rich diet supports a healthier gut environment.
High-fibre complex carbohydrates
Fatigue and lethargy are common symptoms of RA, and erratic blood sugar levels can contribute to this.
High-fibre, complex carbohydrates are digested more slowly and lead to a more stable release of sugar (glucose) into the bloodstream.
Good options include wholegrain or sourdough bread, rolled oats, brown rice, sweet potato, quinoa, and beans and lentils.
Foods worth limiting
Highly processed foods, refined carbohydrates (white bread, sugary cereals, pastries), and foods high in added sugar are associated with higher levels of inflammation.
Some people with RA also report that alcohol worsens their symptoms, though individual responses vary.
Be sure to eat enough, even with lower hunger levels
Mounjaro significantly reduces appetite, and some people find it difficult to eat enough.
Skipping meals or eating very little risks losing muscle mass and missing key nutrients like calcium, vitamin D, and omega-3s.
Second Nature’s balanced plate model can help structure meals even when you’re eating less: fill half the plate with vegetables, a quarter with protein, a quarter with complex carbohydrates, and add a serving of healthy fat like olive oil or avocado.
If you struggle to eat larger main meals, eating smaller portions more frequently can help you get sufficient nutrition without experiencing side effects like nausea.
Movement and RA
Exercise with RA can feel daunting, especially during a flare. But regular movement is one of the most effective ways to manage joint stiffness, maintain strength, and improve overall well-being.
We recommend building an exercise habit gradually and allowing your body time to adapt.
A 10-minute walk after dinner, some gentle stretches in the morning, or a few minutes of movement during a lunch break can be a good starting point as you gradually build the habits into your routine.
Research on habit formation shows that building a small, consistent routine matters more than the intensity or duration of exercise.
Lally et al. (2010) found that it takes an average of 66 days to form a new habit, but the range is wide, so there’s no need to feel pressure about timelines.4
Water-based exercise
Swimming and aquatic exercise are particularly well-suited to RA. The water supports body weight, reducing stress on inflamed joints, while the warmth of a heated pool can ease stiffness.
A 2022 systematic review found that aquatic exercise improved pain, disease activity, and physical function in people with inflammatory arthritis.5
For someone on Mounjaro who is also losing weight, water-based exercise offers a way to stay active without aggravating joint symptoms.
Building strength
Resistance training helps protect against the muscle loss that both RA and weight loss can cause. This doesn’t mean you need to lift heavy weights in a gym. Bodyweight exercises, resistance bands, or light dumbbells all work.
Starting with exercises that target the larger muscle groups, like sit-to-stand movements or wall press-ups, builds a foundation without placing excessive strain on smaller, more vulnerable joints.
If you’re unsure where to begin, a physiotherapist with experience in inflammatory conditions can help you find exercises that work for your current disease activity.
Range-of-motion exercises
Gentle range-of-motion exercises help maintain joint flexibility and can be done daily regardless of how you’re feeling. These include wrist circles, ankle rotations, and gentle shoulder rolls.
On days when a flare makes other exercise difficult, range-of-motion movements keep joints mobile without adding inflammation.
Living with RA and your mental health
RA isn’t just a joint condition. Chronic pain, fatigue, and the unpredictability of flares take a toll on mental health.
A systematic review found that around 17% of people with RA meet the criteria for major depressive disorder, with broader measures of depressive symptoms reaching 39%.6
That’s roughly twice the rate seen in the general population, and it’s likely underreported.
Why RA affects mental health
Chronic pain is exhausting, and the fatigue that comes with RA goes beyond normal tiredness. Many people describe it as a deep, unshakeable exhaustion that affects concentration, motivation, and mood.
Changes in what you can physically do, whether that’s struggling with buttons, needing help with household tasks, or giving up activities you enjoyed, can affect self-esteem and identity.
Body image is another factor. Joint swelling, weight changes (from RA itself, medications, or reduced activity), and visible joint deformity can all influence how people feel about their bodies.
Recognising when to ask for help
It’s normal to feel frustrated or low when managing a chronic condition.
But if low mood, persistent anxiety, or feelings of hopelessness last for more than a couple of weeks, speaking to your GP or rheumatology team is worthwhile.
Psychological support, whether through talking therapies like CBT (a structured approach to managing unhelpful thought patterns), counselling, or peer support groups, can make a meaningful difference.
If you’re starting Mounjaro while managing RA, it’s worth being aware that any period of change, including changes to your body, routine, or medication, can affect how you feel mentally.
Mounjaro and RA at a glance
| Factor |
Details |
| Can you take Mounjaro with RA? |
Yes, Mounjaro isn’t contraindicated in RA |
| Does Mounjaro treat RA? |
No, it’s not licensed for RA. It may help reduce inflammation indirectly through weight loss |
| Evidence level |
One conference abstract (152 patients, retrospective). No large randomised controlled trials yet1 |
| Weight loss with Mounjaro |
Up to 26% after two years in clinical trials2 |
| Inflammatory markers |
Reductions in ESR and CRP observed in the conference abstract1 |
| RA medications |
Continue all prescribed RA treatments. Mounjaro is an addition, not a replacement |
| Key dietary focus |
A diet based on whole foods that includes omega-3-rich foods, adequate protein, colourful vegetables, and complex carbohydrates |
| Exercise considerations |
Water-based exercise, resistance training, and range-of-motion exercises. Adapt to flare days |
Frequently asked questions
Does Mounjaro interact with RA medications like methotrexate?
There are no known direct interactions between Mounjaro and common RA medications such as methotrexate, hydroxychloroquine, or biologic therapies.
However, Mounjaro slows gastric emptying, which can affect how quickly oral medications are absorbed. Let your rheumatologist know if you’re starting Mounjaro so they can monitor your treatment.
Will Mounjaro reduce my RA flares?
Mounjaro isn’t designed to treat RA, so it shouldn’t be expected to prevent flares. The conference abstract showed improvements in inflammatory markers, but this is early evidence from a small, retrospective study.1
Reducing body weight may ease symptoms over time, but your disease-modifying medications remain the primary treatment for managing flares.
Can I take Mounjaro if I’m on steroids for RA?
Yes, but it’s worth discussing with your doctor. Corticosteroids like prednisolone can increase blood sugar levels, and Mounjaro lowers them.
Your healthcare team may want to monitor your blood sugar more closely, especially when starting or changing steroid doses.
Will losing weight on Mounjaro make my RA worse?
Weight loss is generally beneficial for RA. Lower body weight reduces mechanical stress on joints and lowers systemic inflammation.
However, rapid weight loss can cause muscle loss, which is a concern with RA. Eating enough protein and staying active helps protect muscle mass while losing weight.
Should I take omega-3 supplements alongside Mounjaro?
Omega-3 supplements are generally safe and may offer modest benefits for RA symptoms, particularly the tender joint count.3
Oily fish are a good source of omega-3s if you don’t want to take supplements. If you’re considering supplements, speak to your GP first, especially if you’re on blood-thinning medications.
How do I exercise during an RA flare while on Mounjaro?
During a flare, reduce the intensity of exercise but try to keep moving if possible. Gentle range-of-motion exercises, like wrist circles and ankle rotations, help maintain flexibility without stressing inflamed joints.
On better days, you can gradually return to your usual activities.
Is Mounjaro safe for long-term use with RA?
Mounjaro has been studied for up to two years in clinical weight loss trials and has shown a sustained safety profile.2
However, there are no long-term studies specifically examining Mounjaro use in people with RA.
Regular check-ins with your healthcare team are important to monitor both your RA and any side effects from Mounjaro.
Can Mounjaro help with the fatigue that comes with RA?
There’s no direct evidence that Mounjaro reduces RA-related fatigue. However, losing weight, eating well, and being more active can all improve energy levels over time.
Some people also report that the reduced inflammation associated with weight loss helps them feel less tired, though this is anecdotal rather than proven.
Do I need to follow a special diet while taking Mounjaro with RA?
There’s no single diet prescribed for RA, but an eating pattern rich in omega-3 fatty acids, colourful vegetables, adequate protein, and complex carbohydrates supports both joint health and weight management.
The balanced plate model (half vegetables, quarter protein, quarter complex carbohydrates, plus healthy fat) is a practical framework for structuring meals.
Take home message
Mounjaro is safe to take if you have rheumatoid arthritis, and early research suggests that weight loss from anti-obesity medications may improve some inflammatory markers and pain scores in people with RA.
The evidence is still limited to a single conference abstract, so it’s too early to say whether Mounjaro has specific anti-inflammatory benefits for RA beyond what comes from losing weight. Your disease-modifying RA medications remain essential.
Your eating habits and overall lifestyle can help to manage the condition alongside medication. Omega-3-rich foods, adequate protein, and a variety of vegetables support both joint health and weight management.
Second Nature’s medication-supported programme combines Mounjaro with registered dietitian support and a structured behaviour change programme. In a 12-month outcomes study, active subscribers achieved an average weight loss of 19.1%, with 77.7% achieving 10% or more of their body weight lost.7
Gentle, consistent movement, particularly water-based exercise, helps maintain strength and flexibility without aggravating symptoms.
RA is a condition that affects far more than joints, and looking after your mental health is just as important as managing physical symptoms.
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
- Dente, E. et al. (2024). Effects of anti-obesity medications in RA patients. Arthritis & Rheumatology, 76(supplement 9). Conference abstract.
- Aronne, L.J. et al. (2024). Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity. JAMA, 331(1), 38-48.
- Wang, W. et al. (2024). Effects of omega-3 supplementation on lipid metabolism, inflammation, and disease activity in rheumatoid arthritis: a meta-analysis of randomized controlled trials. Clinical Rheumatology, 43(8), 2479-2488.
- Lally, P. et al. (2010). How are habits formed: modelling habit formation in the real world. European Journal of Social Psychology, 40(6), 998-1009.
- Medrado, L.N. et al. (2022). Effectiveness of aquatic exercise in the treatment of inflammatory arthritis: systematic review. Rheumatology International, 42(10), 1681-1691.
- Matcham, F. et al. (2013). The prevalence of depression in rheumatoid arthritis: a systematic review and meta-analysis. Rheumatology, 52(12), 2136-2148.
- Richards, R. et al. (2025). Evaluating weight and health outcomes in a digitally delivered weight management programme with adjunctive GLP-1 RA pharmacotherapy. JMIR Formative Research, 9(1), e72577.
