How to Boost Your Immune System: Best Vitamins and What Works (UK)

Can you actually boost your immune system?

Not in the way adverts suggest. Your immune system is a network of cells, proteins and organs that has to stay balanced, not a muscle you can pump up. A healthy one is already working at the right level.

Catching colds is also normal. A Cochrane review notes that adults have two to four colds a year on average, and children six to eight. Getting a few colds every winter doesn’t mean your immunity is weak.

What you can do is remove the things that drag it down (short sleep, smoking, heavy drinking, long-term stress, nutrient gaps) and protect yourself with vaccines and good hygiene.

Best vitamins and minerals for the immune system (UK)

For most UK adults, the best vitamin for the immune system is the one you’re actually short of, and in autumn and winter that is usually vitamin D. The NHS says most people should get all the nutrients they need from a varied and balanced diet, and vitamin D from October to March is the one supplement it advises everyone to consider.

In Great Britain, only health claims on the official GB nutrition and health claims register can be used. Ten vitamins and minerals carry an authorised immune claim: vitamin D, vitamin C, zinc, vitamin A, selenium, vitamin B6, vitamin B12, folate, copper and iron. The claim can only be used for a food or supplement that provides a meaningful amount of the nutrient. Herbs, mushrooms, probiotics and CBD have no authorised immune claims in GB.

“Normal function” is the key phrase. These nutrients only help if you’d otherwise fall short: topping up beyond what you need doesn’t make your immune system work better, and for some nutrients too much can harm. Here’s each one with the claim as it appears on the register and the NHS daily amount for adults.

Safe upper amounts: do you need a supplement?

If you do take supplements, add up everything you take, including multivitamins and “immune” sachets, and keep under the NHS safe upper amounts.

iTired as well as catching everything going? Ask your GP about a blood test. See iron deficiency symptoms, iron-rich foods, vitamin B12 deficiency symptoms and why you feel so tired in winter. For how zinc compares with magnesium, see magnesium vs zinc.

Vitamin C and zinc together

Vitamin C and zinc are often sold together as an “immune” combination, and taking them together is fine as long as you stay within the NHS amounts. Just be realistic about what they do. In the Cochrane reviews, taking vitamin C every day didn’t stop most people catching colds, though colds were about 8% shorter in adults. Taking zinc regularly made little or no difference to catching a cold, and the evidence that it shortens one is low certainty.

The real risk is doubling up. A multivitamin, an effervescent “immune” tablet and a pack of cold lozenges can easily take you past 25mg of zinc a day, and high doses of zinc reduce how much copper your body absorbs. Keep vitamin C under 1,000mg a day to avoid stomach pain and diarrhoea. For the detail, see our guides to vitamin C and zinc.

Is a multivitamin worth it for immunity?

Not if you already eat well. A multivitamin can’t push a healthy immune system above normal, and the NHS says most people get what they need from a varied, balanced diet. It can be a sensible safety net if your diet is limited, for example if you’re vegan, have a small appetite or are cutting out whole food groups.

If you do take one, check three things: that it gives you 10 micrograms of vitamin D for the winter months, that you aren’t also taking separate vitamin D, zinc or vitamin C that pushes you over the upper amounts above, and that it suits your stage of life. If you’re pregnant, the NHS says not to take cod liver oil or supplements containing vitamin A (retinol), so use a pregnancy supplement instead. Our multivitamins guide covers what the big trials found and how to read a label. Remedies like elderberry and echinacea are herbs, not vitamins, and have no authorised immune claims.

Vitamin D: the one the NHS says to take

Between October and early March, the sun in the UK isn’t strong enough for your body to make the vitamin D it needs. That’s why the NHS says everyone, including pregnant and breastfeeding women, should consider a daily supplement of 10 micrograms of vitamin D in autumn and winter. Adults who rarely go outdoors, live in a care home or usually cover most of their skin outdoors are advised to take it all year, and people with dark skin may need it all year too. Adults shouldn’t take more than 100 micrograms (4,000 IU) a day.

Does it prevent infections? A 2021 meta-analysis of 46 trials and more than 75,000 people found vitamin D supplements slightly reduced the chance of an acute respiratory infection overall (61.3% vs 62.3% had at least one), with a clearer effect when taken daily at 400 to 1,000 IU (10 to 25 micrograms). But the UK CORONAVIT trial of 6,200 adults found that testing people and giving vitamin D to those with lower levels didn’t reduce respiratory infections or COVID-19. So take it because the NHS advises it, not as a shield against colds.

For more, see how much vitamin D to take in winter, vitamin D deficiency symptoms and taking magnesium and vitamin D together.

Popular immune boosters: what the evidence says

Here’s what the best reviews found for the most popular “immune boosting supplements”. In GB, no immune claims are authorised for echinacea, elderberry, garlic, probiotics or mushrooms, so this is a summary of the research, not a recommendation.

Vitamin C and colds

The Cochrane review of vitamin C (2013) found that taking at least 200mg a day didn’t reduce how often people in the general population caught colds. It did slightly shorten them: by 8% in adults and 14% in children. The exception was people under intense physical stress, such as marathon runners, whose risk roughly halved. Starting vitamin C once a cold had begun showed no consistent benefit. The NHS says you can get all the vitamin C you need from your diet.

What about megadoses? Many “immune” tablets and fizzy drinks now hold 1,000mg, 25 times the 40mg adults need. The review authors concluded that routine vitamin C supplements aren’t justified for the general population, and the NHS says more than 1,000mg a day can cause stomach pain, diarrhoea and wind. More is not better: see our vitamin C guide.

Zinc lozenges

The 2024 Cochrane review of zinc (34 trials, 8,526 people) found taking zinc regularly may make little or no difference to your chance of catching a cold. Taken as a treatment once symptoms start, it may shorten a cold by around 2 days, but the trials varied hugely and the evidence is low certainty. If you try them, keep to the dose on the pack, and the NHS says not to take more than 25mg of zinc a day from supplements unless a doctor advises it.

Echinacea, elderberry and garlic

The Cochrane review of echinacea (24 trials) found it hasn’t been shown to help treat colds, with at most a weak, questionable effect on prevention. Elderberry has only 5 small trials, with uncertain results, and garlic just one. If you take regular medicines, check with a pharmacist before trying any herbal remedy. More in our guides to echinacea and elderberry.

Probiotics, mushrooms and ginger shots

Probiotics have the most promising data of the herbal and “natural” options. A 2022 Cochrane review of 23 trials (6,950 children, adults and older people) found people taking probiotics were about 24% less likely to get at least one nose or throat infection, but the evidence was low certainty and the trials used many different strains. See do probiotics work?

Turkey tail, shiitake and reishi are widely sold for immunity, but most of the research is in cells, animals or people with specific illnesses, not healthy adults avoiding colds. See turkey tail. Wellness shots are popular every winter too: we looked at what’s really in ginger shots.

How to make your immune system stronger: 8 habits

1. Sleep at least 7 hours

In a 2015 study, 164 healthy adults wore sleep trackers for a week and were then given cold virus nose drops in quarantine. Those who had slept under 5 hours a night were about 4.5 times as likely to develop a cold as those sleeping more than 7 hours, and those sleeping 5 to 6 hours about 4.2 times as likely. People sleeping 6 to 7 hours had no clearly higher risk.

If you struggle to get enough, see our guides to sleep hygiene and the effects of sleep deprivation.

2. Don’t smoke

Smoking damages the lining of the airways and dampens the immune response. A review in Archives of Internal Medicine found smokers have a 2 to 4 times higher risk of invasive pneumococcal disease, and that flu is several times more common and much more severe in smokers.

3. Keep alcohol within the guidelines

A meta-analysis found pneumonia risk climbed with every level of drinking. Compared with non-drinkers, 24g of alcohol a day (3 UK units, as one unit is 8g) was linked to a 12% higher risk, 60g a day to a 33% higher risk, and alcohol use disorder to about 8 times the risk. The NHS advises no more than 14 units a week on a regular basis.

4. Manage long-term stress

In a classic study in the New England Journal of Medicine, 394 healthy adults were given cold viruses. The share who developed a cold rose from about 27% to 47% as their stress scores went up, even after allowing for smoking, alcohol, exercise, diet and sleep. See stress symptoms and how to relieve stress.

5. Move most days

In a study of 1,002 adults followed through autumn and winter, those doing aerobic exercise 5 or more days a week had 43% fewer days with colds and similar infections than people who were mostly inactive, and milder symptoms. It was observational, so active people may differ in other ways. The NHS recommends at least 150 minutes of moderate activity a week, such as brisk walking, plus strengthening exercises on 2 or more days.

6. Eat a varied, mostly plant-rich diet

Your immune system needs a steady supply of nutrients (see the table above), and a varied diet with vegetables, fruit, pulses, wholegrains, nuts and enough protein covers most of them. See gut health and food and mood.

7. Keep up good hygiene

The NHS advises washing your hands often with warm water and soap, catching coughs and sneezes in tissues, not sharing towels or cups, and not touching your eyes and nose.

8. Get your vaccines

Vaccines are the one proven way to prime your immune system against a specific infection. See who’s eligible below, and for a whole-season plan see our winter wellness guide.

NHS flu and COVID vaccines this winter

In England, the NHS offers a free flu vaccine for 2026 to 2027 if you:

• are aged 65 or over (including those who will be 65 by 31 March 2027)
• are aged 18 to 64 and have certain long-term health conditions
• are pregnant (at any stage of pregnancy)
• live in a care home
• are the main carer for an older or disabled person, or receive Carer’s Allowance
• live with someone who has a weakened immune system
• are aged 16 or over and sleeping rough or staying in a hostel or night shelter

iThe NHS advises getting it as soon as you can; the last date is 31 March 2027. You can book online, in the NHS App, at a pharmacy or through your GP surgery. Wondering what to expect afterwards? See flu jab side effects and how long they last.

The winter COVID-19 vaccine is offered to people aged 75 or over (including those who turn 75 by 31 January 2027), people aged 6 months to 74 years with a weakened immune system because of a health condition or treatment, and people living in care homes for older adults. The last date is 31 January 2027.

iScotland, Wales and Northern Ireland run their own programmes, so check NHS inform, NHS 111 Wales or nidirect.

Foods and a simple winter soup

“Immune boosting soup” is one of the fastest-rising searches every autumn. To be straight with you: no soup boosts your immune system, and that isn’t a claim we can make. What a good homemade soup does give you is useful, especially when you’re run down or have a cold:

• Fluids. The NHS advises drinking plenty of fluids when you have a cold, and a warm bowl is an easy way to do it when you don’t feel like eating.
• Vegetables. Vegetables cooked in soups count towards your 5 A Day, and 80g is one portion. Pulses such as lentils count too, but only once a day however many you eat.
• Protein. Chicken, beans or lentils make it a proper meal rather than a starter.
• Nutrients on the list above. Leafy greens bring folate, carrots bring beta-carotene, and chicken brings B6, B12 and zinc.

What about chicken soup? A much-quoted 2000 lab study found chicken soup slowed the movement of a type of white blood cell in a dish. It was done in a lab, not in people with colds, so it can’t tell you that soup changes how your body fights an infection. The comfort is real; the “cure” isn’t proven.

Quick chicken (or bean) and lentil winter soup

Serves 4. About 40 minutes. Freezes well.

• 1 tbsp olive or rapeseed oil
• 1 onion, 2 carrots and 2 celery sticks, chopped
• 2 garlic cloves and a thumb of fresh ginger, grated
• 100g red lentils, rinsed
• 1.2 litres low-salt chicken or vegetable stock
• 2 skinless chicken thighs, or a 400g tin of cannellini beans (drained) for a vegan version
• 2 big handfuls of spinach or shredded kale
• Half a lemon, black pepper and fresh parsley to finish

1. Soften the onion, carrot and celery in the oil over a medium heat for 8 to 10 minutes.
2. Stir in the garlic and ginger for a minute, then add the lentils, stock and chicken thighs.
3. Simmer for 25 minutes, until the lentils are soft and the chicken is cooked through. Lift the chicken out, shred it with two forks and return it (or add the beans now).
4. Stir in the greens for 2 minutes until wilted. Finish with a squeeze of lemon, pepper and parsley.

Each bowl gives you more than 80g of vegetables plus lentils, so at least two of your 5 A Day, along with protein and plenty of fluid. For more ideas, see our guides to garlic, ginger, high-fibre foods and gut health.

Immune-boosting foods and other myths

• “This food boosts your immune system.” No single food does. Citrus, garlic and ginger are fine in a healthy diet, but the overall pattern matters, not a superfood or a daily ginger shot.
• “More vitamin C is better.” Above 1,000mg a day you’re more likely to get stomach pain and diarrhoea than extra protection, according to the NHS.
• “Immune booster supplements work.” A supplement can only fill a gap. If you’re not short of a nutrient, extra won’t make your immune system work harder, and high doses of some (zinc, vitamin A, selenium) can cause harm.
• “Cold showers and saunas strengthen immunity.” The evidence on infections is limited. See our honest guides to cold showers and sauna benefits.
• “Mushrooms boost immunity.” No immune health claims are authorised for them in GB, and the evidence in healthy adults is very limited (see the boosters section above). Our functional mushrooms guide covers each one.
• “CBD boosts the immune system.” CBD has no authorised health claims, and we don’t make immune claims for it.

Our products are for adults (18+) only. We don’t recommend our products during pregnancy or breastfeeding.

The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.

How to boost your immune system when you’re sick

There’s no way to “boost” your immune system fast once a cold starts, but you can help yourself feel better while it runs its course. First check whether it’s a cold or flu: see cold vs flu. The NHS says most people feel better in about 1 to 2 weeks. It advises:

• getting plenty of rest
• drinking lots of fluids, such as water, to avoid dehydration
• gargling salt water for a sore throat (adults only), or breathing in steam from a hot shower for a blocked nose (more in our sore throat remedies guide)
• asking a pharmacist about paracetamol or ibuprofen
• not smoking, as it can make symptoms worse

Wash your hands often and use tissues so you don’t pass it on. Sleep is harder with a blocked nose, so see our tips on how to sleep with a cold. For building better long-term routines, see how to build healthy habits.

Why is my immune system so weak? When to see a GP

If you feel you catch everything going, your immune system may not be weak at all. Two to four colds a year is average for adults, and children have six to eight, so living or working with young children means more chances to catch one. But some everyday things can wear your defences down, and some medicines and conditions genuinely weaken the immune system.

Common reasons you keep getting ill

• Short sleep. Sleeping under 5 to 6 hours a night was linked to a much higher chance of catching a cold in the study above. See sleep deprivation.
• Long-term stress. Higher stress scores meant more colds in the cold virus studies. See stress symptoms.
• A poor or restricted diet. Low iron or vitamin B12 can leave you tired and run down, and a GP can test for these and for vitamin D.
• Alcohol and smoking. Both raise the risk of chest infections such as pneumonia and flu, as covered above.
• Some medicines. The NHS lists chemotherapy, biological therapy or radiotherapy, steroid medicine (depending on the dose) and long-term immunosuppressive treatment for conditions such as lupus, rheumatoid arthritis, inflammatory bowel disease, scleroderma or psoriasis.
• Some health conditions. These include blood cancers such as leukaemia, lymphoma or myeloma, HIV, an organ, bone marrow or stem cell transplant, and rare genetic disorders of the immune system. If you have a long-term condition such as diabetes, or a heart, lung or kidney condition, the NHS advises seeing a GP when you get cold symptoms.

If you take a medicine that affects your immune system, don’t stop it or add supplements without talking to your GP, specialist or pharmacist first.

Signs it might be more than bad luck

A few colds a year is normal. Immunodeficiency UK, the patient charity, suggests thinking about an immune problem when infections are severe, persistent, unusual or recurrent, or when immunodeficiency runs in the family. That might look like:

• frequent infections that keep coming back
• infections that are severe or last much longer than they should
• unusual infections that most people don’t get

Its list of warning signs also includes needing antibiotics through a drip (intravenous) to clear infections, two or more pneumonias within three years, two or more new sinus infections within a year, and thrush or fungal infections that last more than six months.

See a GP if any of these sound familiar. A GP can ask about your infection history and arrange blood tests if needed, and may refer you to an immunologist. Also see a GP with a cold if your high temperature lasts more than 3 days, your symptoms don’t improve after 10 days, your cough lasts more than 3 weeks, you’re short of breath or have chest pain, or you have a long-term condition or weakened immune system.

Related guides

• Cold vs flu: how to tell them apart and when to get help.
• Vitamin D: morning or night, with food and with K2.
• Sea moss gel is often marketed for immunity; see what the sea moss research actually shows.
• For what the lab studies on breathing and immunity really show, see our guide to Wim Hof breathing benefits and risks.
• Do probiotics work? for what the research shows on colds and when they are worth trying.
• Repeat cold sores are common when you’re run down. See our guide to cold sore triggers and what helps.
• Does manuka honey support immunity? The honest evidence.
• What the research on shiitake and immunity really shows.
• Flu jab side effects and how long they last.
• What cordyceps trials show on immune markers.
• A weakened immune system makes shingles more likely; see shingles symptoms and who can get the NHS vaccine.
• For which type of vitamin D to choose, see vitamin D vs D3.
• Wondering about wellness shots? We looked at the evidence behind ginger shots, including how much vitamin C one really holds.
• Thinking about a mushroom supplement anyway? Our guide to the best mushroom supplements in the UK covers what labels should state and who should avoid reishi.
• For men, our guide to supplements for men over 50 and 40 covers which vitamins are worth taking at each age.
• Taking extra vitamin D for winter? Stay within the NHS limit: see too much vitamin D.