Immune Wellness
Supporting Immune Health: A Starting Guide
Your immune system is a network that defends the body, not a switch you can turn up. Supporting normal immune function mostly means looking after the basics, keeping vaccines up to date, and being realistic about what products can do.
General information, not medical advice. Last updated October 31, 2026. Written by the AlternativeMed editorial team. Not medically reviewed.
Start here
- Get the vaccines recommended for you and wash your hands often with soap and water.
- Look after the basics: regular sleep, not smoking, and being active in a way you enjoy.
- Treat "immune boosting" products with care: ask a pharmacist or doctor first if you take medicines, are pregnant, or have an immune or autoimmune condition.
Be careful with
- "Boosting" is a poor goal. The immune system can be too weak (frequent or severe infections) or too active (allergies, autoimmune disease), so a product that pushes everything up is not clearly good.
- Natural does not mean safe. Echinacea can cause allergic reactions, raw elderberry is poisonous, and some herbs may interact with medicines, especially medicines that suppress the immune system.
- Antibiotics do not work on viruses such as colds, and no supplement is proven to cure or prevent flu or COVID-19.
Get help when
- Infections that keep coming back, do not clear up, or are unusually severe for the germ involved.
- A high temperature lasting more than 3 days, symptoms that get worse, shortness of breath or chest pain, or no improvement after 10 days.
- Fever with a stiff neck and headache needs emergency care (MedlinePlus advises emergency help for this combination).
- If you take immune-suppressing medicines, such as chemotherapy or corticosteroids, a fever or new cough with breathlessness needs a call to your care team right away.
- Always talk to a clinician first about infections in babies, older adults, during pregnancy, or with a weakened immune system.
About Supporting Immune Health: A Starting Guide
What the immune system is
MedlinePlus describes the immune system as a network of cells, tissues and organs that helps the body fight infections and other diseases. It includes the skin, the moist linings called mucous membranes that trap germs, white blood cells, and lymph organs such as the thymus, spleen, lymph nodes and bone marrow.
Innate immunity is the protection you are born with and is the first line of defence. Adaptive (active) immunity develops after an infection or a vaccination, usually lasts a long time, and lets the body recognise and respond quickly to a germ it has met before.
1Four goals that get mixed together
Many immune claims blur four different aims: correcting a shortage of a nutrient, preventing infection, shortening an illness, and easing symptoms. A product can help with one and do nothing for another. For example, vitamin D has been studied for preventing respiratory infections, while honey and rest are about easing symptoms.
Look for outcomes that matter to you, such as fewer colds or fewer days ill, rather than laboratory markers such as cell counts.
2,3Common experiences
Colds are part of normal life. Getting a few a year does not mean your immunity is weak. The NHS notes you can spread a cold from a few days before symptoms start until they have finished.
Feeling run down, catching whatever is going around, or taking time to recover can have many causes, including poor sleep, stress and other illnesses. See the goal on why you keep getting sick if infections feel frequent.
4What affects normal immune function
Studies in healthy volunteers who were deliberately exposed to a cold virus found that people sleeping under 5 hours, or 5 to 6 hours, a night were more likely to develop a cold than those sleeping more than 7 hours. Another pair of viral-challenge studies found that people with recent long-lasting stressful experiences were at higher risk of a cold. These are observational links, not proof that fixing sleep or stress prevents colds.
Smoking is associated with a higher chance of hospital admission after influenza. Age, long-term conditions, some medicines, and some inherited or acquired conditions also change how the immune system works.
5,6,7,8When the immune system does not work normally
MedlinePlus describes two broad patterns. In immunodeficiency, the response is reduced or absent, so infections can be more frequent, more severe or slower to clear. Causes include inherited conditions, HIV, some cancers, malnutrition, and medicines such as corticosteroids and chemotherapy.
In autoimmune disease the immune system mistakenly attacks healthy cells; there are more than 80 such diseases. Allergies and asthma are other examples of a response to something harmless. This is why a general push to "boost" immunity is oversimplified.
1,8,9Realistic expectations and who this applies to
No food, habit or supplement makes you immune to infection. The steps with the strongest support are vaccines and hand hygiene; habits such as sleep, activity and not smoking are sensible but their effect on infections is less certain.
This page suits healthy adults who want a plain map. People with immune or autoimmune conditions, transplant recipients, people having chemotherapy, pregnant or breastfeeding people, children and older adults should check with a clinician before changing supplements.
3,10Related conditions and symptoms
Immunodeficiency, autoimmune conditions and immunosuppression → Allergies vs colds →
A manageable starting plan
An educational starting point, not a personal prescription. Adjust it to your own situation and any advice from your clinician.
Your first actions
- Check which vaccines you are due for and book them.
- Wash hands with soap for around 20 seconds at key moments.
- Protect a regular sleep window and, if you smoke, ask for stop-smoking support.
Optional additions
- Add moderate activity you enjoy most days.
- Build one stress-easing habit into your week.
- If you suspect low vitamin D or a limited diet, ask about testing.
What to track
- Number of colds or infections over a few months and how long each lasts.
- Sleep hours on most nights.
- Any supplements you take, so you can show them to a clinician.
When to reassess
Review after two to three months. A few colds a year is normal; if infections are frequent, severe or slow to clear, book a clinician visit instead of adding products.
When to seek professional support
- See a clinician about recurrent or severe infections.
- Ask a pharmacist before combining supplements with medicines.
- People with immune or autoimmune conditions should get advice from their specialist before using any immune supplement.
What helps
Ordered by how well the research supports each step. Evidence strength is shown on every card; precautions sit next to the advice.
Start here
Vaccines recommended for you
High certaintyAddresses: Protection against specific infections before you meet them
Why it may help: WHO describes vaccination as protecting people from harmful diseases by using the body's own defences: the immune system learns to recognise the germ, makes antibodies and remembers how to respond. Vaccines contain killed or weakened germs, parts of them, or genetic instructions for an antigen, so they do not cause the disease. For influenza, a Cochrane review of 52 trials found inactivated vaccines probably reduce influenza in healthy adults from 2.3% to 0.9% (moderate-certainty evidence), with a smaller reduction in influenza-like illness.
How to apply it: Ask your clinician or pharmacist which vaccines are recommended for your age, health and pregnancy status, and keep a record of what you have had.
Who it may suit: Everyone; especially older adults, pregnant people, and people with long-term conditions, who should follow their national schedule and clinician advice.
Precautions: Tell your clinician about allergies or if you are immunocompromised, since advice on some vaccines differs. The NHS notes the flu vaccine does not prevent colds.
10,11,4Washing hands with soap and water
High certaintyAddresses: Fewer germs passed between people and surfaces
Why it may help: The NHS says washing removes dirt, bacteria and viruses, limits their spread and helps prevent illnesses such as flu, food poisoning and diarrhoea. It advises scrubbing for around 20 seconds, and using alcohol-based sanitiser if soap and water are not available.
How to apply it: Wash after the toilet, after coughing, sneezing or blowing your nose, before eating or preparing food, and after touching animals. Use tissues and bin them promptly.
Who it may suit: Everyone.
Precautions: Frequent washing can dry skin; moisturise afterwards.
12,4Regular, sufficient sleep
Low certaintyAddresses: May lower the chance of catching a cold
Why it may help: In a viral-challenge study of 164 healthy adults, those who slept under 5 hours or 5 to 6 hours a night (measured with a wrist monitor) were more likely to develop a cold than those sleeping more than 7 hours; 6 to 7 hours carried no clear extra risk. The NHLBI recommends a regular sleep schedule and a quiet, cool, dark bedroom.
How to apply it: Keep a regular bed and wake time, limit caffeine and alcohol late in the day, and keep the bedroom quiet, cool and dark.
Who it may suit: Adults with short or irregular sleep.
Precautions: This is an association in one study, not proof. Persistent poor sleep deserves a doctor's attention.
5,13Not smoking (and avoiding smoke)
Moderate certaintyAddresses: Lower chance of serious illness after influenza
Why it may help: A systematic review of 12 observational studies (18,612 people) found ever-active smokers had higher odds of hospital admission (OR 1.5) and ICU admission (OR 2.2) after influenza than never-smokers. The NHS also lists smoking as something to avoid when you have a cold.
How to apply it: If you smoke, ask a clinician or stop-smoking service for support. Avoid second-hand smoke, especially around children.
Who it may suit: Smokers and people around them.
Precautions: Observational evidence, so it shows association; the review found no clear link with deaths because of few studies.
7,4Additional options
Regular moderate activity
Low certaintyAddresses: May ease how severe respiratory infections feel
Why it may help: A Cochrane review of 14 trials (1,377 adults) found exercise did not change how many respiratory infections people had or how long each lasted, but reduced symptom severity and the number of symptom days over follow-up. Certainty was low to moderate.
How to apply it: Choose moderate activity you enjoy, such as walking or cycling, most days.
Who it may suit: Most healthy adults.
Precautions: If you feel feverish or unwell, rest. Check with a clinician before starting if you have a heart or lung condition.
14Managing long-lasting stress
Low certaintyAddresses: May be linked with fewer colds
Why it may help: Two viral-challenge studies (276 and 79 adults) found that people with recent long-term threatening stress showed reduced response to the body's anti-inflammatory signal and were more likely to develop a cold afterwards. It does not show that stress-reduction programmes prevent infection.
How to apply it: Build in rest, connection and calming routines; see the stress pages for approaches.
Who it may suit: Anyone under prolonged strain.
Precautions: If stress is overwhelming or affects daily life, talk to a clinician.
6A varied diet and checking for deficiency
Moderate certaintyAddresses: Corrects a shortage if you have one
Why it may help: A deficiency is the clearest case where a nutrient matters for immunity. In a meta-analysis of 25 trials (10,933 participants), vitamin D supplementation reduced the odds of acute respiratory infection overall (adjusted OR 0.88), with the strongest effect in people with very low starting levels, and no extra serious adverse events were seen. Benefit in people who already have adequate levels was small.
How to apply it: If you suspect low vitamin D or another shortage (restricted diet, little sun, absorption problems), ask a clinician about testing before supplementing.
Who it may suit: People with limited diets, little sunlight exposure, or conditions affecting absorption.
Precautions: More is not better; high doses of some vitamins can cause harm. Ask a clinician or pharmacist, especially in pregnancy.
2Still being studied
Vitamin C taken every day
Moderate certaintyAddresses: Little effect on how many colds ordinary people get
Why it may help: A Cochrane review of 29 trial comparisons (11,306 participants) found a pooled risk ratio of 0.97 for catching a cold in the general community, so routine supplementation is not justified. Regular use shortened colds slightly (8% in adults, 14% in children). In 598 marathon runners, skiers and soldiers on subarctic exercises, risk was roughly halved (RR 0.48).
How to apply it: Eat fruit and vegetables for vitamin C; supplements are optional and mostly useful only for specific groups.
Who it may suit: People under brief heavy physical stress were the group that benefited in trials.
Precautions: Large supplement amounts can upset the stomach; ask a clinician if you have kidney stones or take medicines.
15Echinacea
Mixed findingsAddresses: May slightly lower the chance of catching a cold
Why it may help: NCCIH says echinacea may slightly reduce your chance of catching a cold and it is unclear whether it shortens one. Products differ widely, so one extract's results may not apply to another. Some people have allergic reactions, which can be severe, and it belongs to the daisy family.
How to apply it: Only after checking with a clinician if you take medicines.
Who it may suit: Healthy adults without daisy-family allergy, for short periods.
Precautions: Avoid if you have a daisy-family allergy; theoretical concern about immunosuppressants; consult a provider in pregnancy or for children.
16,4Elderberry
Low certaintyAddresses: Possible relief of cold and flu symptoms
Why it may help: NCCIH says a small number of studies looked at colds, flu and other upper respiratory infections and preliminary research suggests it may relieve symptoms. There is no good evidence it helps with COVID-19.
How to apply it: Use only cooked or properly prepared commercial products.
Who it may suit: Healthy adults; not enough information for pregnancy or breastfeeding.
Precautions: Raw or unripe berries and other parts of the elder tree contain cyanide-producing substances that can cause nausea, vomiting and severe diarrhoea; cooking removes the toxin.
17Immune-support supplement blends in general
Not enough evidenceAddresses: Unclear for healthy people
Why it may help: A systematic review of 39 randomised studies in healthy people (echinacea, elderberry, garlic, vitamins A, C, D, E and zinc) found some hints of benefit but gaps that prevent firm conclusions. Immune-health products make up about 10% of US dietary supplement sales.
How to apply it: Treat as optional and uncertain; do not rely on them in place of vaccines or care.
Who it may suit: Healthy adults.
Precautions: Combination products can hide interactions and high doses; check with a pharmacist.
3Food & nutrition
Food and nutrition
We did not find a food or diet that has been shown to prevent infections in healthy people. A varied diet that meets your nutrient needs is the sensible base, and a true deficiency is the clearest case where a nutrient affects immunity. MedlinePlus lists malnutrition among the causes of reduced immune response.
Vitamin D supplements reduced respiratory infections in a large pooled analysis, mainly in people starting with very low levels. Regular vitamin C did not reduce colds in the general population. Details by nutrient are on the nutrition goal page.
- Vitamin C from fruit and vegetables is fine; routine supplements did not lower cold rates in the general community.
- Vitamin D matters most when levels are low; ask about testing.
- Cook elderberries; never eat them raw.
Fluids and rest when you have a cold
The NHS advises rest and keeping up fluids to avoid dehydration, a salt-water gargle or a warm lemon and honey drink for a sore throat, and says not to give honey to children under 12 months.
4Remedies & supplements
Traditional use, laboratory findings and human trials are kept apart. "Natural" does not mean safe.
Echinacea
Mixed findingsStudied form and route: Extracts, tablets or teas (products vary)
Intended outcome: May slightly lower the chance of catching a cold
Human evidence: NCCIH: may slightly reduce your chances of catching a cold; unclear whether it shortens a cold.
Traditional use: Used traditionally for colds and infections.
Laboratory findings: We did not find a human outcome linked to lab findings in the sources we read.
Limits: Products differ in species, plant part and extraction, so results do not transfer between products.
Interactions and precautions: Allergic reactions can be severe; daisy-family allergy; theoretical concern with immunosuppressants; discuss in pregnancy and with children.
16Elderberry
Low certaintyStudied form and route: Cooked or commercial syrups and extracts
Intended outcome: Possible symptom relief for colds and flu
Human evidence: NCCIH: a small number of studies; preliminary research suggests it may relieve symptoms. No good evidence for COVID-19.
Traditional use: Long used as a folk remedy.
Laboratory findings: We did not find lab findings to report from the sources read.
Limits: Few small studies.
Interactions and precautions: Raw or unripe berries and other elder tree parts are poisonous; little known for pregnancy or breastfeeding.
17Vitamin D
Moderate certaintyStudied form and route: Daily supplement
Intended outcome: Fewer acute respiratory infections, mainly if levels are very low
Human evidence: Meta-analysis of 25 trials (10,933 participants): adjusted OR 0.88 overall; stronger in those with levels below 25 nmol/L; best with daily or weekly rather than large bolus doses.
Traditional use: We did not find traditional-use claims in the sources read.
Laboratory findings: We did not read lab studies for this page.
Limits: Effect in people with adequate levels was small.
Interactions and precautions: Ask a clinician about testing and amount; high doses can cause harm.
2Vitamin C
Moderate certaintyStudied form and route: Daily supplement
Intended outcome: Slightly shorter colds with regular use
Human evidence: Cochrane: no reduction in colds in the general population (RR 0.97); colds 8% shorter in adults and 14% in children with regular use; no consistent effect when started after symptoms began.
Traditional use: We did not find traditional-use claims in the sources read.
Laboratory findings: We did not read lab studies for this page.
Limits: Benefit for catching colds seen only in people under brief heavy physical stress.
Interactions and precautions: Ask a clinician if you take medicines or have kidney problems.
15Garlic and medicinal mushrooms
Not enough evidenceStudied form and route: Supplements
Intended outcome: Immune support claims
Human evidence: The NHS says there is little evidence garlic prevents colds. We did not find human trials in healthy people showing mushrooms prevent infections in the sources read for this page.
Traditional use: Both have traditional use for general health.
Laboratory findings: Lab and animal findings are not evidence of fewer infections.
Limits: Very little human research on infection outcomes.
Interactions and precautions: Garlic supplements may add to bleeding risk with blood thinners or before surgery; check mushrooms with a clinician if you have an autoimmune condition.
4,3Therapies & care
Established care for immune problems is general-medical: a clinician can check for causes of frequent or severe infections, review medicines, and offer recommended vaccines. Nothing on this page replaces that care, and prescribed medicines should never be stopped without the prescriber's advice.
Vaccination services
High certaintyPreventive care Clinics and pharmacies give vaccines recommended for your age and health, and keep your record.
Who it may suit: Everyone, with advice for people who are pregnant or immunocompromised.
Precautions: Tell the vaccinator about allergies and immune conditions.
10,11Vaccines and infection prevention → Preventive care for older adults →
Medical assessment of recurrent or severe infections
High certaintyClinical evaluation MedlinePlus lists infections that recur, do not clear up, or are severe for the germ involved as warning signs of immunodeficiency; a provider can investigate.
Who it may suit: People with a pattern of unusual infections or a family history of immunodeficiency.
Precautions: People on chemotherapy or corticosteroids with a fever should seek care right away.
8What to avoid
Habits, products and claims that can get in the way. Never stop a prescribed medicine without talking to the professional who prescribed it.
Risks that apply to most people
Relying on supplements instead of vaccines or medical care
High certaintyWhy: No supplement has been shown to replace vaccination, and the NHS says there is little evidence that vitamin C, echinacea or garlic prevent colds or speed recovery.
Who it applies to: Anyone tempted by "immune booster" marketing.
Try instead: Use vaccines and hygiene first; add supplements only if you and a clinician agree.
4,10Smoking and second-hand smoke
Moderate certaintyWhy: Smokers had higher odds of hospital admission after influenza.
Who it applies to: Smokers and households with children.
Try instead: Seek stop-smoking support; keep smoke away from children.
7Personal triggers to check
Regularly sleeping under about 6 hours
Low certaintyWhy: Short sleep was linked with a higher chance of developing a cold after virus exposure.
Who it applies to: Adults with demanding schedules.
Try instead: Protect a regular sleep window; see the sleep goals.
5,13Going to work or school sharing cups and towels while ill
Moderate certaintyWhy: The NHS advises not sharing towels, cups or toys and notes you can spread a cold from days before symptoms to the end.
Who it applies to: Households and workplaces.
Try instead: Use tissues, wash hands, avoid sharing items.
4Products that need caution
High-dose or combined immune supplements without advice
Low certaintyWhy: Evidence in healthy people is limited, and combination products may interact with medicines or be unsuitable for immune conditions.
Who it applies to: People with autoimmune disease, on immunosuppressants, pregnant or breastfeeding.
Try instead: Ask a pharmacist or clinician first; see the safety pages.
3,16Medication interactions → Immune safety and when to get help →
Raw elderberry or homemade elder preparations
High certaintyWhy: Raw or unripe berries and other parts of the elder tree contain cyanide-producing substances.
Who it applies to: Anyone making their own remedies.
Try instead: Do not eat raw elderberries; cooked preparations remove the toxin.
17Unsupported claims
"Boost your immune system"
High certaintyWhy: The immune system is a network that can be underactive or overactive, so more activity is not automatically better; lab markers are not the same as fewer infections.
Who it applies to: Product labels and social media.
Try instead: Look for fewer colds or fewer days of illness in human trials.
1,9,3"Antibiotics for a cold"
High certaintyWhy: The NHS says antibiotics do not help colds because they are caused by viruses.
Who it applies to: Anyone with cold or flu symptoms.
Try instead: Rest, fluids and symptom care; see a GP if symptoms worsen or last long.
4Common mistakes
Ignoring repeated or severe infections
High certaintyWhy: Infections that keep coming back or are severe for the germ involved can signal an immune problem.
Who it applies to: Anyone with a pattern of illness.
Try instead: See a clinician; MedlinePlus lists recurrent and severe infections as warning signs.
8Taking supplements while on immune-suppressing medicine without asking
Moderate certaintyWhy: There is a theoretical concern about interactions between echinacea and immunosuppressants; MedlinePlus notes some medicines suppress immunity.
Who it applies to: Transplant, autoimmune and cancer patients.
Try instead: Ask the prescriber; never stop a prescribed medicine on your own.
16,8Evidence & safety
What the research shows
The best-supported ways to protect yourself are vaccines and hand hygiene. Sleep, not smoking and activity are sensible habits with smaller or less certain effects on infections. Supplements and herbs show mixed to insufficient evidence in healthy people, except that vitamin D helps most when levels are very low. Evidence labels: high, moderate, low, mixed, insufficient.
Limits of the evidence
- Several findings (sleep, stress, smoking) are observational or from small viral-challenge studies and show association, not cause.
- Supplement trials are small, use different products, and often measure lab markers rather than infections.
- We read agency pages and PubMed records; we did not read every trial inside the reviews.
Precautions and interactions
- Natural does not mean safe; check herbs and supplements with a pharmacist if you take any medicine.
- Echinacea and similar products may be unsuitable with immunosuppressants or autoimmune disease.
- Do not stop or change prescribed medicines because of anything on this page.
Life-stage considerations
- Pregnancy and breastfeeding: little is known about elderberry safety; echinacea use should be discussed with a clinician; vaccines in pregnancy should follow clinician advice.
- Children: do not give honey to under-12-month-olds; echinacea caused rashes in some children in a trial; talk to a child's clinician first.
- Older adults and people with long-term conditions: seek care sooner for infections and ask about recommended vaccines.
Warning signs
- Fever with stiff neck and headache needs emergency care.
- High temperature for more than 3 days, worsening symptoms, shortness of breath or chest pain.
- No improvement after 10 days, or a cough lasting over 3 weeks.
- Recurrent or severe infections, or repeated oral thrush.
- Fever of 38 C (100.5 F) or higher, or new cough with breathlessness, while on chemotherapy or corticosteroids.
Claim checks
You can boost your immune system with a product
Not enough evidenceThe immune system can be underactive or overactive; reviews of supplement ingredients could not make firm statements, and lab markers do not equal fewer infections.
1,3Vitamin C stops colds
Moderate certaintyNot in the general population (RR 0.97); small benefit in duration with regular use; a different result in people under brief heavy exertion.
15,4Echinacea prevents colds
Mixed findingsMay slightly lower the chance, according to NCCIH; products differ and the evidence is mixed.
16Vaccines make you ill with the disease
High certaintyWHO says vaccines contain killed or weakened germs, parts of them, or genetic instructions for an antigen, and trigger an immune response without causing the disease.
10Antibiotics help with colds
Evidence againstThe NHS says antibiotics do not help because colds are caused by viruses.
4Vitamin D prevents chest infections for everyone
Moderate certaintyA pooled analysis found a modest overall reduction in odds, with the largest effect in people with very low levels and little effect when levels were adequate.
2Questions people ask
Can I boost my immune system?
Not in a simple on and off way. The immune system is a network, and too much activity is also a problem, as in allergies and autoimmune disease. Supporting normal function means looking after the basics.
What is the most reliable way to lower my infection risk?
Vaccines recommended for you and good handwashing are the best-supported steps. WHO describes how vaccines train the immune system, and the NHS says handwashing helps prevent illnesses such as flu.
Do vitamin C, echinacea or garlic stop colds?
The NHS says there is little evidence that they prevent colds or speed recovery. NCCIH says echinacea may slightly reduce the chance of catching one, with mixed evidence.
How many colds are normal?
Colds are common. We did not find a single number to quote from the sources read, but a few a year is ordinary; infections that keep coming back or are severe deserve a check.
Does sleep affect catching a cold?
In one viral-challenge study of 164 adults, people sleeping under 5 hours or 5 to 6 hours a night were more likely to get a cold than those sleeping more than 7 hours. It shows an association.
Does exercise help my immune system?
A Cochrane review found exercise did not change how many respiratory infections people had, but it reduced symptom severity and symptom days. Certainty was low to moderate.
Should I take vitamin D for immunity?
A large pooled analysis found vitamin D reduced respiratory infections mainly in people with very low starting levels. Ask a clinician about testing rather than guessing.
Is elderberry safe?
Cooked or properly prepared products are used, but raw or unripe berries and other parts of the elder tree contain cyanide-producing substances. Little is known about pregnancy or breastfeeding.
Are immune supplements safe with an autoimmune condition?
Not necessarily. Autoimmune disease involves an overactive response, and there is a theoretical concern about echinacea and immunosuppressants. Ask your specialist first.
Do antibiotics help colds or flu?
No. The NHS says antibiotics do not help colds because they are caused by viruses.
When should I see a doctor?
For infections that recur, do not clear up or are severe; for a high temperature over 3 days, breathlessness, chest pain, or no improvement after 10 days; and straight away for fever with stiff neck and headache.
References
- MedlinePlus (U.S. National Library of Medicine). Immune System and Disorders. Read 2026-10-31. source
- Martineau AR, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017. PubMed record read 2026-10-31. source
- Crawford C, et al. Select Dietary Supplement Ingredients for Preserving and Protecting the Immune System in Healthy Individuals: A Systematic Review. Nutrients. 2022. PubMed record read 2026-10-31. source
- NHS. Common cold. Read 2026-10-31. source
- Prather AA, et al. Behaviorally Assessed Sleep and Susceptibility to the Common Cold. Sleep. 2015. PubMed record read 2026-10-31. source
- Cohen S, et al. Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proc Natl Acad Sci U S A. 2012. PubMed record read 2026-10-31. source
- Han L, et al. Smoking and Influenza-associated Morbidity and Mortality: A Systematic Review and Meta-analysis. Epidemiology. 2019. PubMed record read 2026-10-31. source
- MedlinePlus Medical Encyclopedia. Immunodeficiency diseases. Read 2026-10-31. source
- MedlinePlus. Autoimmune Diseases. Read 2026-10-31. source
- World Health Organization. Vaccines and immunization: What is vaccination? Read 2026-10-31. source
- Demicheli V, et al. Vaccines for preventing influenza in healthy adults. Cochrane Database Syst Rev. 2018. PubMed record read 2026-10-31. source
- NHS. How to wash your hands. Read 2026-10-31. source
- NHLBI. Healthy Sleep Habits. Read 2026-10-31. source
- Grande AJ, et al. Exercise versus no exercise for the occurrence, severity, and duration of acute respiratory infections. Cochrane Database Syst Rev. 2020. PubMed record read 2026-10-31. source
- Hemila H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013. PubMed record read 2026-10-31. source
- NCCIH (NIH). Echinacea: Usefulness and Safety. Read 2026-10-31. source
- NCCIH (NIH). Elderberry: Usefulness and Safety. Read 2026-10-31. source
Related on AlternativeMed
Related goals
Build Everyday Immune-Supportive Habits → Meet Your Nutritional Needs for Immune Health → Prepare for Cold & Flu Season → Reduce Your Risk of Common Infections → Understand Why You Keep Getting Sick → Support Recovery From Common Illness → Return to Your Routine After Illness →
Ingredients, foods and supplements
Echinacea → Elderberry → Garlic → Echinacea, elderberry, garlic and mushrooms →
Research, safety and claim-check resources
How the immune system works → Immune safety and when to get help → Immune research and evidence → Cough and sore throat remedies → Medication interactions → Immune wellness hub →