There’s no pill or drink that “boosts” a healthy immune system beyond normal. What you can do is give it what it needs to work well. The good news is that the habits with the strongest evidence are free.
What actually supports your immune system
1. Sleep 7 to 9 hours
People who sleep less than 6 hours a night are more likely to catch a cold when exposed to the virus. Regular sleep is one of the most effective things you can do.
2. Keep your vaccines up to date
Vaccines train your immune system to recognise specific infections. In the US, adults are advised to get a yearly flu vaccine and stay up to date with COVID-19 and other recommended vaccines.
3. Eat a varied diet
- Plenty of fruit and vegetables for vitamin C, vitamin A and fibre
- Protein at each meal (beans, fish, eggs, dairy, meat)
- Zinc from meat, shellfish, beans, nuts and whole grains
- Fermented foods like yogurt may support healthy gut bacteria, which play a role in immunity
4. Move every day
Regular moderate exercise, such as 30 minutes of brisk walking most days, is linked to fewer colds. Very intense training without rest can have the opposite effect.
5. Manage stress
Long-term stress raises cortisol, which can dampen immune responses. Sleep, exercise, time outdoors and talking to people all help.
6. Don’t smoke, and keep alcohol low
Smoking damages the lining of the airways, and heavy drinking weakens immune defences.
7. Wash your hands
Washing with soap for 20 seconds, especially before eating and after being in public places, cuts the spread of colds and stomach bugs.
Do supplements help?
- Vitamin C: taking it daily may shorten colds slightly, but doesn’t prevent them for most people. See vitamin C for colds.
- Vitamin D: may help people who are low in it. Ask your doctor about a blood test, especially in winter.
- Zinc lozenges: started within 24 hours of cold symptoms may shorten a cold. They can cause a bad taste and nausea.
- Herbal products: Ayurvedic herbs such as guduchi (giloy) and formulas like Himalaya Septilin and Himalaya Guduchi are traditionally used to support the body’s defences. Evidence in people is limited. Giloy has been linked to rare cases of liver injury, especially in people with autoimmune conditions, so check with a doctor first if you have liver disease, an autoimmune condition, diabetes or take other medicines.
Supplements can’t make up for poor sleep or diet, and more isn’t better: very high doses of some vitamins and minerals can cause harm.
When to see a doctor
- You get infections very often, or they take a long time to clear
- You have a fever that lasts more than 3 days, or trouble breathing
- You lose weight without trying, or have night sweats
- You have a condition or take a medicine that weakens immunity
Frequently asked questions
What is the fastest way to boost your immune system?
There’s no quick fix. Good sleep, a varied diet, regular activity and up-to-date vaccines are what make the biggest difference.
Does giloy boost immunity?
Giloy is traditionally used for immunity in Ayurveda, but evidence in people is limited, and rare liver problems have been reported. Talk to a doctor before using it, especially if you have a health condition.
Which vitamins help the immune system?
Vitamins C, D and A and the mineral zinc all play a role. Most people get enough from a varied diet; supplements mainly help people who are low.
More in our Everyday Health guide: all our articles and products on this topic in one place.
This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Supplements are not evaluated by the FDA to diagnose, treat, cure or prevent any disease.
