What is multiple sclerosis?

A friendly, practical guide to understanding multiple sclerosis or MS—what it is, who it affects, why it matters, and how science is changing the outlook
Multiple sclerosis (MS) is a complex, lifelong condition that affects the brain and spinal cord, often changing how people move, feel, and experience the world. This deep dive explores what multiple sclerosis is, how it develops, what causes it, how it’s diagnosed, and what treatments and lifestyle strategies can help. We’ll break down the science in plain English, share real-world tips, and keep things honest and relatable—because living with MS is about more than just medical facts.

Five key takeaways

• MS is a neurological condition that affects the brain and spinal cord, causing a wide range of symptoms that can come and go or gradually worsen over time [1], [2].
• The exact cause is unknown, but it’s linked to a mix of genes, environment, and lifestyle factors like vitamin D, viral infections, and smoking [2], [3].
• Early diagnosis and modern treatments are helping people with MS live fuller, more active lives than ever before [2].
• There’s no cure yet, but a combination of disease-modifying therapies, symptom management, and lifestyle tweaks can make a big difference [1], [2].
• Support, understanding, and up-to-date information empower people with MS and their loved ones to navigate the journey with confidence.

Who is this article for?

This guide is for anyone curious about MS—whether you’re newly diagnosed, supporting a loved one, or want to understand this often-misunderstood condition. We’re here to break down the science, share real-world advice, and help you feel more confident navigating MS.

Introduction: What is multiple sclerosis?

Multiple sclerosis, or  MS, is the most common non-traumatic disabling disease in young adults, but it can affect anyone [4]. It’s a lifelong, often unpredictable condition where the immune system mistakenly attacks the protective covering of nerves (myelin) in the brain and spinal cord [5]. This can slow down or block messages between the brain and the rest of the body, leading to a wide range of symptoms [5].

MS is different for everyone. Some people have mild symptoms that come and go, while others may experience more persistent challenges. Thanks to advances in science, early diagnosis and treatment are changing what it means to live with MS [1], [2].

Who gets MS, and why?

MS can affect anyone, but it’s most often diagnosed in people in their 20s and 30s, with women about three times more likely to develop it than men [2]. The causes of multiple sclerosis aren’t fully understood, but research points to a combination of:

• Genetic factors: Having a close relative with MS slightly increases your risk, but most people with MS don’t have a family history [6].
• Environmental factors: Things like low vitamin D (less sunlight), certain viral infections (especially Epstein–Barr virus), childhood obesity, and smoking all play a role [2],  [3].
• Geography: MS is more common in countries further from the equator, possibly due to differences in sunlight and vitamin D levels [7].

It’s a bit like a jigsaw puzzle—genes, environment, and lifestyle all fit together to influence MS risk. But no single factor “causes” MS on its own [2].

What happens in the body: The science of MS

In MS, the immune system—which normally protects us from infections—gets confused and attacks the myelin sheath, the fatty covering that insulates nerves. This damage disrupts the flow of electrical signals in the central nervous system, leading to the symptoms of MS [2], [5].

Imagine an electric cable with damaged insulation: the signal gets weaker, slower, or lost altogether. Over time, repeated attacks can also damage the underlying nerve fibres, causing lasting problems [5].

MS is often described as having two main phases:

1. Relapsing-remitting MS (RRMS): Most people are diagnosed with this type. Symptoms flare up (relapses), then improve (remission). Over time, relapses can leave lasting effects [1], [2].
2. Progressive MS: In some people, MS gradually worsens from the start (primary progressive MS), or it becomes steadily worse after a relapsing phase (secondary progressive MS) [1], [2].

Researchers used to think MS was purely a T-cell (a type of white blood cell) problem, but the success of new treatments targeting B-cells (another immune cell) has changed our understanding [8].

What are the symptoms of multiple sclerosis?

MS symptoms can be unpredictable and vary from person to person. Some of the most common include:

• Fatigue: Not just feeling tired, but a deep, persistent exhaustion that doesn’t always improve with rest [1].
• Vision problems: Blurred or double vision, pain when moving the eyes, or even temporary vision loss [1].
• Muscle weakness and stiffness: Often in the legs, making walking tricky [1].
• Numbness or tingling: Usually in the limbs or face [1].
• Balance and coordination issues: Feeling unsteady, clumsy, or dizzy [1].
• Bladder and bowel problems: Needing to go urgently or frequently, or difficulty controlling these functions [1].
• Cognitive changes: Trouble with memory, attention, or thinking clearly [1].
• Mood changes: Depression and anxiety are more common in people with MS [1]

Symptoms can come and go, especially in the early stages. Some people have long periods without problems, while others may notice a gradual worsening over time [1], [2].

How is multiple sclerosis diagnosed?

Getting a diagnosis of MS can be a journey, as there’s no single test that can confirm it. Doctors use a combination of:

• Medical history and symptoms: Looking for patterns of neurological problems that come and go.
• Neurological examination: Testing reflexes, strength, coordination, and sensation.
• MRI scans: These can show areas of damage (lesions) in the brain and spinal cord [1], [2].
• Lumbar puncture (spinal tap): Checking for specific proteins in the fluid around the brain and spine [1], [2].
• Blood tests: To rule out other conditions that can mimic MS.

Diagnosis is based on showing that damage has occurred in different parts of the nervous system at different times. It can take time, and sometimes more than one scan or test is needed [1], [2].

What causes multiple sclerosis?

The million-pound question! While we don’t know the exact cause, it’s clear that a mix of genetic and environmental factors triggers MS [2]. Here’s what we know:

• Genes: More than 150 genetic variations have been linked to MS, but each one only slightly increases the risk. The primary gene involved is HLA-DRB1*15:01[2].
• Vitamin D: Low levels are linked to a higher risk, which may explain why MS is more common in countries with less sunlight [2].
• Viral infections: Especially Epstein–Barr virus, which causes glandular fever. Having this infection, especially in adolescence, seems to double the risk [2].
• Smoking: Increases risk by about 50% and may make MS worse if you already have it.
• Obesity in childhood or adolescence: Linked to a higher risk of developing MS later on [2], [3].

Several of these factors likely need to come together at just the wrong time for MS to develop. The good news? Some are modifiable—so healthy lifestyle choices really do matter [2].

What are the types of MS?

MS isn’t one-size-fits-all. There are several types, and understanding them helps people make sense of their symptoms and treatment options:

• Relapsing-remitting MS (RRMS): The most common form, with periods of new or worsening symptoms (relapses) followed by recovery (remissions) [2].
• Secondary progressive MS (SPMS): Many people with RRMS eventually develop this type, where symptoms gradually worsen with fewer relapses [2].
• Primary progressive MS (PPMS): From the start, symptoms steadily get worse, without clear relapses or remissions [2].

Some people are diagnosed with clinically isolated syndrome (CIS)—a first episode of symptoms that could be MS, but not enough evidence to confirm the diagnosis yet [2].

How is MS treated?

There’s currently no cure for MS, but there’s a growing toolkit of treatments that can help manage the disease, reduce relapses, and slow progression. These include:

Disease-modifying therapies (DMTs)

These medicines target the immune system to reduce inflammation and nerve damage. They’re most effective when started early and are tailored to each person’s type of MS and lifestyle. Examples include interferon beta, glatiramer acetate, fingolimod, natalizumab, ocrelizumab, and more [2], [3].

Symptom management

This covers a wide range, from medicines for pain, muscle spasms, and bladder issues, to physiotherapy, occupational therapy, and mental health support. Some people find complementary therapies like mindfulness, yoga, or acupuncture helpful—though always check with your MS team first  [1].

Lifestyle and wellness

Regular exercise (even gentle movement), a balanced diet, good sleep, and not smoking all help. Staying socially connected and seeking support when needed makes a big difference [2].

New and future treatments

Research is moving fast. Newer therapies, including immune reconstitution treatments and even stem cell transplants, are offering hope of long-term remission for some. Trials are ongoing into treatments for progressive MS and ways to repair myelin [2].

Another medicine that many people with MS are having success with is low-dose naltrexone.

Low-dose naltrexone (LDN) and multiple sclerosis (MS): quick summary

• Background: LDN has been proposed as a potential therapy for MS since 2005 [10]. Early pilot studies and clinical trials have explored its safety, tolerability, and effects on symptoms and quality of life in people with MS [11].

Clinical studies:

• A multi-centre pilot trial in primary progressive MS showed LDN was well tolerated and reduced muscle spasticity [11].
• Retrospective and prospective studies (mostly in relapsing-remitting MS) report that most patients had no side effects, with some experiencing improved fatigue and quality of life [12].
• Randomised controlled trials found mixed results: one showed no difference in overall quality of life, while another found significant improvement in mental health components [13], [14].
• Low-dose naltrexone appears safe to use alongside standard MS therapies, with no evidence of worsening disease activity or abnormal blood/organ function over several years of use [15].

Mechanisms:

• LDN is thought to work in MS by increasing ?-endorphins and restoring levels of opioid growth factor, which may help regulate immune function and reduce inflammation [9].

• Animal studies show low-dose naltrexone may suppress harmful immune cell activity and promote a more favourable immune response, potentially slowing disease progression and improving neurological function [16].

Safety:

• LDN is generally well tolerated, with insomnia and vivid dreams being the most common side effects [15].
• No significant changes in standard lab tests or increased risk of disease progression were observed in human studies [15].

Bottom line:

LDN is a promising, well-tolerated adjunct therapy for MS, with potential benefits for spasticity, fatigue, and quality of life, but larger, high-quality clinical trials are needed to confirm its effectiveness. It appears safe to use alongside standard MS treatments and may have immune-modulating effects relevant to MS.

Living with MS: Real-world tips and support

Living with MS is about more than just managing symptoms. Here are some practical tips from people who’ve been there:

• Stay informed: Knowledge is power, but stick to trusted sources like the NHS, MS Society, and your healthcare team.
• Build your support network: Friends, family, and MS specialists can help you navigate the ups and downs.
• Pace yourself: Fatigue is real—plan activities with breaks and don’t be afraid to ask for help.
• Look after your mental health: It’s normal to feel anxious or low at times. Talking therapies, mindfulness, and support groups can help.
• Celebrate the wins: Whether it’s a good day, a new skill, or just getting out for a walk, every achievement counts.

FAQs: What is multiple sclerosis?

What is multiple sclerosis in simple terms?

MS is a condition where the immune system damages the protective covering of nerves in the brain and spinal cord, causing a range of symptoms that can come and go or get worse over time.

How is MS diagnosed?

Through a combination of medical history, neurological exams, MRI scans, and sometimes a lumbar puncture. Diagnosis can take time and may need several tests.

Can MS be cured?

There’s no cure yet, but treatments can help manage symptoms, reduce relapses, and slow progression.

Who gets MS?

Anyone can get MS, but it’s most common in young adults and more often affects women.

What causes MS?

A mix of genes, environment, and lifestyle—like low vitamin D, certain viruses, and smoking—all play a part.

How does Courier Pharmacy support people with MS?

At Courier Pharmacy, we’re dedicated to making life easier for people with MS and their families. We offer straightforward, reliable access to prescription and over-the-counter medicines—including low-dose naltrexone (LDN), which you can order directly through our online pharmacy.

Our expert pharmacy team is always on hand to provide advice and answer your questions, ensuring you get the support you need. With fast, discreet delivery and a focus on convenience, we help take the hassle out of managing MS—so you can focus on what matters most.

This information is for general guidance only. For medical advice, please consult your doctor or healthcare provider.

References

1. NHS (2024) Multiple sclerosis. Available at: https://www.nhs.uk/conditions/multiple-sclerosis/ (Accessed: 18 August 2025)
2. Dobson, R. and Giovannoni, G., 2019. Multiple sclerosis–a review. European journal of neurology, 26(1), pp.27-40.
3. Ascherio, A., 2013. Environmental factors in multiple sclerosis. Expert review of neurotherapeutics, 13(sup2), pp.3-9.
4. Kobelt, G., Thompson, A., Berg, J., Gannedahl, M., Eriksson, J., MSCOI Study Group and European Multiple Sclerosis Platform, 2017. New insights into the burden and costs of multiple sclerosis in Europe. Multiple Sclerosis Journal, 23(8), pp.1123-1136.
5. Karussis, D., 2014. The diagnosis of multiple sclerosis and the various related demyelinating syndromes: a critical review. Journal of autoimmunity, 48, pp.134-142.
6. Hollenbach, J.A. and Oksenberg, J.R., 2015. The immunogenetics of multiple sclerosis: A comprehensive review. Journal of autoimmunity, 64, pp.13-25.
7. Koch-Henriksen, N. and Sørensen, P.S., 2010. The changing demographic pattern of multiple sclerosis epidemiology. The Lancet Neurology, 9(5), pp.520-532.
8. Greenfield, A.L. and Hauser, S.L., 2018. B?cell Therapy for Multiple Sclerosis: Entering an era. Annals of Neurology, 83(1), pp.13-26.
9. Courier Pharmacy (2025). How does low-dose naltrexone (LDN) work? Available at: https://courierpharmacy.co.uk/how-does-ldn-work/ (Accessed: 18 August 2025)
10. Agrawal, Y.P., 2005. Low-dose naltrexone therapy in multiple sclerosis. Medical hypotheses, 64(4), pp.721-724.
11. Gironi, M., Martinelli-Boneschi, F., Sacerdote, P., Solaro, C., Zaffaroni, M., Cavarretta, R., Moiola, L., Bucello, S., Radaelli, M., Pilato, V. and Rodegher, M.E., 2008. A pilot trial of low-dose naltrexone in primary progressive multiple sclerosis. Multiple Sclerosis Journal, 14(8), pp.1076-1083.
12. Turel, A.P., Oh, K.H., Zagon, I.S. and McLaughlin, P.J., 2015. Low-dose naltrexone for treatment of multiple sclerosis: a retrospective chart review of safety and tolerability. Journal of Clinical Psychopharmacology, 35(5), pp.609-611.
13. Sharafaddinzadeh, N., Moghtaderi, A., Kashipazha, D., Majdinasab, N. and Shalbafan, B., 2010. The effect of low-dose naltrexone on the quality of life of patients with multiple sclerosis: a randomised placebo-controlled trial. Multiple Sclerosis Journal, 16(8), pp.964-969.
14. Cree, B.A., Kornyeyeva, E. and Goodin, D.S., 2010. Pilot trial of low?dose naltrexone and quality of life in multiple sclerosis. Annals of Neurology, 68(2), pp.145-150.
15. Toljan, K. and Vrooman, B., 2018. Low-dose naltrexone (LDN)—review of therapeutic utilisation. Medical Sciences, 6(4), p.82.
16. Rahn, K.A., McLaughlin, P.J. and Zagon, I.S., 2011. Prevention and diminished expression of experimental autoimmune encephalomyelitis by low-dose naltrexone (LDN) or opioid growth factor (OGF) for an extended period: Therapeutic implications for multiple sclerosis. Brain research, 1381, pp.243-253.

Byline

Written by Shazlee Ahsan, Medical writer at Courier Pharmacy. Content reviewed by a registered pharmacist and based on clinical studies, patient stories, and up-to-date guidelines.

How this content was created

This article was researched and written by a professional copywriter, reviewed by a registered pharmacist, and shaped by real patient experiences. All information is based on clinical studies and trusted sources, with references provided for further reading.