Influenza, Common Colds and Symptoms: 4+1 products for “immediate” protection

If every winter various symptoms “knock on your door” and you wonder whether it’s the influenza or just a common cold, you’re not alone. And that’s where the familiar dilemma begins: “What should I take to get through it more easily?” or “Is there something that helps prevent it?” The truth is that there are no “magic” solutions - only supportive tools backed by scientific data, which can be added to your toolkit so you’re better prepared the next time the common cold or the influenza comes knocking.

Let’s look together at what the research shows - until new evidence emerges.

Influenza & common cold: what’s the key difference?

Common cold: caused mainly by rhinoviruses and is usually milder.
Typical symptoms include:

Runny nose
Sneezing
Mild sore throat
Low fever or no fever

Influenza: caused by Influenza A and B viruses and tends to start more abruptly and feel more “severe.”

Influenza A & B: what to expect in symptoms and duration

Influenza type A

It is often responsible for most seasonal outbreaks. Typical symptoms include:

High fever
Muscle/joint aches
Headache, chills
Dry cough
Intense feeling of weakness

In Influenza A, the acute phase usually lasts 5–7 days, but fatigue can last up to 14 days.

Influenza type B

Often milder, but can present more intensely in children/teens.
Symptoms:

Fever
Sore throat
Headache
Muscle pain

When you should be cautious

If you have intense symptoms, belong to a higher-risk group, or symptoms “get out of hand” (e.g., persist or worsen), the safest move is medical guidance. Especially with influenza, early intervention plays an important role in effective management.

Influenza vaccine: the foundation of prevention

The vaccine remains the #1 preventive measure. Interestingly, some systematic reviews suggest that probiotics/prebiotics may positively affect antibody response after vaccination (especially in certain groups, e.g., older adults).

Dietary supplements: 4+1 options with scientific support

1) Antioxidant nutrients (e.g., vitamin C, zinc, selenium)

Adequate intake of micronutrients supports normal immune function and has been associated with reduced duration/severity of upper respiratory infections in adults.

The foundation for adequate antioxidant intake is plenty of colorful fruits and vegetables daily. As an additional measure, antioxidant supplementation appears potentially helpful—particularly regarding “how severe” the influenza or common cold may ultimately be. Supplemental vitamin C and zinc are options that may support immune cell activity and the smooth, effective production of our “defense army”—antibodies.

2) Vitamin D

In a meta-analysis of 25 randomized clinical trials Martineau et al. found that supplemental vitamin D3 may be associated with a reduced risk of acute respiratory infections, with greater benefit when baseline levels are low.

3) Probiotics & prebiotics

Recent data note that probiotic supplementation may:

reduce the frequency of upper respiratory infections (in specific contexts) (Coleman JL et al., 2022)
enhance immune response after influenza vaccination (in some studies)

4) Black elderberry (Sambucus nigra)

A meta-analysis of randomized clinical studies (Hawkins J et al., 2019) showed it may help reduce the duration and intensity of upper respiratory symptoms as a complementary option.

+1) Antiviral therapy (when indicated)

When we’re talking about influenza (not a common cold), antiviral drugs are most effective when given within 48 hours of symptom onset, with evidence showing reduced symptom duration and risk of complications in appropriate cases.

Bonus: NAC supplementation

The literature around NAC (N-acetylcysteine) focuses heavily on viral infections (especially COVID-19), with proposed mechanisms such as:

increasing glutathione/antioxidant defenses
regulating an exaggerated inflammatory response
supporting normal respiratory function

Although the data come mainly from COVID-19–related studies, NAC’s mechanisms are broader in relevance to upper respiratory infections, including influenza viruses. It helps thin and clear mucus from the respiratory tract, facilitating the removal of viruses and irritants, while also helping reduce oxidative stress and excessive inflammation that accompany infections.

Possible side effects & safety

Zinc/multivitamins: caution with continuous overdosing and combining multiple products.

Vitamin D: caution with high doses taken long-term.

Probiotics: medical guidance is needed in immunosuppression/serious underlying disease.

Herbal products (e.g., elderberry): caution in special situations/with medication use.

Guidance from a health professional is crucial, as they will determine the duration of use, the dosing approach, and the type appropriate for each individual. In other words, combining products requires an individualized approach because we all have different needs. Finally, it is of utmost importance to evaluate the supplements tried—through lab values (blood tests) and through observing possible deficiency symptoms and symptoms of the common cold or influenza, in case of illness.

In conclusion

Vitamin, mineral and antioxidant supplements do not replace medical treatment or vaccination, but they can work supportively, especially during periods of increased circulation. The modern approach of the interdisciplinary community is multifactorial immune support, focusing on personalization: balanced nutrition, appropriate supplement choices tailored to individual needs, and—of course—appropriate pharmaceutical therapy when deemed necessary.

Nature is by our side in every way, as long as we trust it through the lens of valid scientific knowledge.

Disclaimer: This article is informational and does not replace medical diagnosis or treatment. If you have underlying conditions, are pregnant/breastfeeding, or take medication, consult a doctor/pharmacist/dietitian before starting a supplement.

Scientific References

Abioye AI, Bromage S, Fawzi W. Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis. BMJ Glob Health. 2021 Jan;6(1):e003176. doi: 10.1136/bmjgh-2020-003176. PMID: 33472840; PMCID: PMC7818810.
Arioz Tunc H, Childs CE, Swann JR, Calder PC. The effect of oral probiotics on response to vaccination in older adults: a systematic review of randomised controlled trials. Age Ageing. 2024 May 11;53(Suppl 2):ii70-ii79. doi: 10.1093/ageing/afae033. PMID: 38745493.
Chia Siang Kow, Dinesh Sangarran Ramachandram, Syed Shahzad Hasan & Kaeshaelya Thiruchelvam. (2025) Effect of N-Acetylcysteine on mortality in COVID-19 patients: A systematic review and meta-analysis of randomized controlled trials. Inflammopharmacology 33:8, pages 4871-4877.
Coleman JL, Hatch-McChesney A, Small SD, Allen JT, Sullo E, Agans RT, Fagnant HS, Bukhari AS, Karl JP. Orally Ingested Probiotics, Prebiotics, and Synbiotics as Countermeasures for Respiratory Tract Infections in Nonelderly Adults: A Systematic Review and Meta-Analysis. Adv Nutr. 2022 Dec 22;13(6):2277-2295. doi: 10.1093/advances/nmac086. PMID: 35948276; PMCID: PMC9776651.
Hawkins J, Baker C, Cherry L, Dunne E. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials. Complement Ther Med. 2019 Feb;42:361-365. doi: 10.1016/j.ctim.2018.12.004. Epub 2018 Dec 18. PMID: 30670267.
Martineau AR, Jolliffe DA, Greenberg L, Aloia JF, Bergman P, Dubnov-Raz G, Esposito S, Ganmaa D, Ginde AA, Goodall EC, Grant CC, Janssens W, Jensen ME, Kerley CP, Laaksi I, Manaseki-Holland S, Mauger D, Murdoch DR, Neale R, Rees JR, Simpson S, Stelmach I, Trilok Kumar G, Urashima M, Camargo CA, Griffiths CJ, Hooper RL. Vitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis. Health Technol Assess. 2019 Jan;23(2):1-44. doi: 10.3310/hta23020. PMID: 30675873; PMCID: PMC6369419.
Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, Bergman P, Dubnov-Raz G, Esposito S, Ganmaa D, Ginde AA, Goodall EC, Grant CC, Griffiths CJ, Janssens W, Laaksi I, Manaseki-Holland S, Mauger D, Murdoch DR, Neale R, Rees JR, Simpson S Jr, Stelmach I, Kumar GT, Urashima M, Camargo CA Jr. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017 Feb 15;356:i6583. doi: 10.1136/bmj.i6583. PMID: 28202713; PMCID: PMC5310969. Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, Bergman P, Dubnov-Raz G, Esposito S, Ganmaa D, Ginde AA, Goodall EC, Grant CC, Griffiths CJ, Janssens W, Laaksi I, Manaseki-Holland S, Mauger D, Murdoch DR, Neale R, Rees JR, Simpson S Jr, Stelmach I, Kumar GT, Urashima M, Camargo CA Jr. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017 Feb 15;356:i6583. doi: 10.1136/bmj.i6583. PMID: 28202713; PMCID: PMC5310969.
Stefano Sanduzzi Zamparelli, Alessandro Sanduzzi Zamparelli & Marialuisa Bocchino. (2025) Immune-Boosting and Antiviral Effects of Antioxidants in COVID-19 Pneumonia: A Therapeutic Perspective. Life 15:1, pages 113.
Stelios F. Assimakopoulos, Diamanto Aretha, Dimitris Komninos, Dimitra Dimitropoulou, Maria Lagadinou, Lydia Leonidou, Ioanna Oikonomou, Athanasia Mouzaki & Markos Marangos. (2021) N-acetyl-cysteine reduces the risk for mechanical ventilation and mortality in patients with COVID-19 pneumonia: a two-center retrospective cohort study. Infectious Diseases 53:11, pages 847-854.