What can the average person do for their immunity?

By Nameer van Oosterom BPharm (Hons)

With the current global COVID-19 pandemic, and flu season fast approaching, having a strong immune system has never been more important. There are many things we can do to help support our immune system, and this article will highlight three supplements that may help you! Please note that this advice is general in nature and may depend on your own personal medical background. For more information, please come in store to have a chat to one of our lovely pharmacists.

Vitamin C 

(Ascorbic Acid)

Vitamin C is a vitamin which is essential for human survival but cannot be naturally produces in humans.1 Therefore, ascorbic acid must be obtained from our diet to ensure adequate levels. Many fruits and vegetables contain vitamin C; especially citrus fruits like oranges.1 However, vitamin C supplements are also available commercially.

What is the effectiveness of Vitamin C?

The use of vitamin C for treating viral infections has been controversial, however most clinical trials have found high doses of decrease the duration of cold symptoms by a few days.2-7 This includes a meta-analysis review, which is considered one of the more rigorous reviews of literature. In comparison, there is lacking evidence to support the use of vitamin C is preventing or treating COVID-19. However, due to the safety of vitamin C at normal doses, there are potential benefits of vitamin C outweigh the limited risks.


Zinc is a mineral, and like vitamin C, is an essential nutrient to main normal human physiological processes.10 The human body is unable to store excess amounts of zinc, so we require a constant adequate supply from our diet. Zinc can be found in red meat, poultry, and fish, but also from tofu, legumes, and nuts for those of you who are vegetarian or vegan.10

What is the effectiveness of Zinc?

Zinc has been found to be effective in the treatment of colds, by significantly reducing the duration of symptoms.11-19 However, there is more conflicting evidence for the preventative use of zinc.11, 20, 21 Choosing the right zinc supplement is important, as different formulation have difference evidence, but also, some products contain other ingredients that can reduce the effectiveness of zinc. This is because some ingredients can bind to zinc in a process called chelating, which prevents zinc from being ionised into its active form.22-24 Similar to vitamin C, there is lacking evidence supporting the use of Zinc to treat or prevent COVID-19, however, the risks associated with zinc at normal doses is limited.


Andrographis is a plant which has been cultivated globally but is native to Asian countries including India and Sri Lanka. it has been purported that they can reduce pain (analgesic effect), fever (antipyretic effect), inflammation, and have antiseptic properties.

What is the effectiveness of Andrographis?

Taking Andrographis as an individual supplement, or in combination with others, improves the symptoms of a cold.25-32 It appears treatment should be started within 72hours of symptoms onset, and symptoms start to improve as quickly as 2 days after starting.25-27, 29 Interestingly, there is emerging evidence that Andrographis can help prevent the common cold. A study that used regularly andrographis had a 50% reduction in the risk of developing a cold after 2 months of use.33 Importantly, the same situation applies for andrographis as it does for vitamin C and zinc – there is lacking evidence support andrographis is in treatment or prevention of COVID-19.


  1. Padayatty SJ, Katz A, Wang Y, et al. Vitamin C as an antioxidant: evaluation of its role in disease prevention. J Am Coll Nutr. 2003;22(1):18-35.
  2. Martin NG, Carr AB, Oakeshott JG, Clark P. Co-twin control studies: vitamin C and the common cold. Prog Clin Biol Res 1982;103:365-73.
  3. Pitt HA, Costrini AM. Vitamin C prophylaxis in marine recruits. JAMA 1979;241:908-11 
  4. Anderson TW. Vitamin C and the common cold. J Med Soc N J 1979;76:765-6.
  5. Hemila H. Does vitamin C alleviate the symptoms of the common cold?- a review of current evidence. Scand J Infect Dis 1994;26:1-6
  6. Douglas RM, Chalker EB, Treacy B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev 2000;(2):CD000980.
  7. Gorton HC, Jarvis K. The effectiveness of vitamin C in preventing and relieving the symptoms of virus-induced respiratory infections. J Manipulative Physiol Ther 1999;22:530-3.
  8. Carr AB, Einstein R, Lai LY, et al. Vitamin C and the common cold: using identical twins as controls. Med J Aust 1981;2:411-2..
  9. Hemila, H. and Chalker, E. Vitamin C for preventing and treating the common cold. Cochrane.Database.Syst.Rev. 2013;1:CD000980
  10. Gibson RS. A historical review of progress in the assessment of dietary zinc intake as an indicator of population zinc status. Adv Nutr. 2012 Nov 1;3(6):772-82.
  11. Mossad SB, Macknin ML, Medendorp SV, Mason P. Zinc gluconate lozenges for treating the common cold. A randomized, double-blind, placebo-controlled study. Ann Intern Med 1996;125:81-8.  
  12. Godfrey JC, Conant Sloane B, Smith DS, et al. Zinc gluconate and the common cold: a controlled clinical study. J Int Med Res 1992;20:234-6.  
  13. Al-Nakib W, Higgins PG, Barrow I, et al. Prophylaxis and treatment of rhinovirus colds with zinc gluconate lozenges. J Antimicrob Chemother 1987;20:893-901.  
  14. Farr BM, Conner EM, Betts RF, et al. Two randomized controlled trials of zinc gluconate lozenge therapy of experimentally induced rhinovirus colds. Antimicrob Agents Chemother 1987;31:1183-7. 
  15. Prasad AS, Fitzgerald JT, Bao B, et al. Duration of symptoms and plasma cytokine levels in patients with the common cold treated with zinc acetate. A randomized, double-blind, placebo-controlled trial. Ann Intern Med 2000;133:245-52
  16. Petrus EJ, Lawson KA, Bucci LR, Blum K. Randomized, double-masked, placebo-controlled clinical study of the effectiveness of zinc acetate lozenges on common cold symptoms in allergy-tested subjects. Curr Ther Res 1998;59:595-607.
  17. Zinc lozenges reduce the duration of common cold symptoms. Nutr.Rev. 1997;55(3):82
  18. Hemilä H, Petrus EJ, Fitzgerald JT, Prasad A. Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis. Br J Clin Pharmacol. 2016 Jul 5
  19. Hunter J, Arentz S, Goldenberg J, et al. Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials. BMJ Open. 2021;11(11):e047474. 
  20. Smith DS, Helzner EC, Nuttall CE Jr, et al. Failure of zinc gluconate in treatment of acute upper respiratory tract infections. Antimicrob Agents Chemother 1989;33:646-8. 
  21. Weismann K, Jakobsen JP, Weismann JE, et al. Zinc gluconate lozenges for common cold. A double-blind clinical trial. Dan Med Bull 1990;37:279-81.
  22. Zarembo JE, Godfrey JC, Godfrey NJ. Zinc(II) in saliva: determination of concentrations produced by different formulations of zinc gluconate lozenges containing common excipients. J Pharm Sci 1992;81:128-30..
  23. Eby GA. Zinc ion availability–the determinant of efficacy in zinc lozenge treatment of common colds. J Antimicrob Chemother 1997;40:483-93.
  24. Jackson JL, Lesho E, Peterson C. Zinc and the common cold: a meta-analysis revisited. J Nutr 2000;130:1512S-5S.
  25. Caceres DD, Hancke JL, Burgos RA, et al. Use of visual analogue scale measurements (VAS) to assess the effectiveness of standardized Andrographis paniculata extract SHA-10 in reducing the symptoms of common cold. A randomized, double-blind, placebo study. Phytomedicine 1999;6:217-23
  26. Melchior J, Palm S, Wikman G. Controlled clinical study of standardized Andrographis paniculata in common cold- a pilot trial. Phytomedicine 1996;97;3:315-8.
  27. Hancke J, Burgos R, Caceres D, Wikman G. A double-blind study with a new monodrug Kan Jang: decrease of symptoms and improvement in the recovery from common colds. Phytotherapy Res 1995;9:559-62.
  28. Melchoir J, Spasov AA, Ostrovskij OV, et al. Double-blind, placebo-controlled pilot and phase III study of activity of standardized Andrographis paniculata Herba Nees extract fixed combination (Kan Jang) in the treatment of uncomplicated upper-respiratory tract infection. Phytomedicine 2000;7:341-50
  29. Gabrielian ES, Shukarian AK, Goukasova GI, et al. A double blind, placebo-controlled study of Andrographis paniculata fixed combination Kan Jang in the treatment of acute upper respiratory tract infections including sinusitis. Phytomedicine 2002;9:589-97..
  30. Poolsup N, Suthisisang C, Prathanturarug S, et al. Andrographis paniculata in the symptomatic treatment of uncomplicated upper respiratory tract infection: systematic review of randomized controlled trials. J Clin Pharm Ther 2004;29:37-45.
  31. Spasov AA, Ostrovskij OV, Chernikov MV, Wikman G. Comparative controlled study of Andrographis paniculata fixed combination, Kan Jang and an Echinacea preparation as adjuvant, in the treatment of uncomplicated respiratory disease in children. Phytother Res 2004;18:47-53
  32. Hu XY, Wu RH, Logue M, et al. Andrographis paniculata (Chuan Xin Lián) for symptomatic relief of acute respiratory tract infections in adults and children: a systematic review and meta-analysis. PLoS One 2017;12(8):e0181780.
  33. Caceres DD, Hancke JL, Burgos RA, Wikman GK. Prevention of common colds with Andrographis Paniculata dried extract: a pilot, double-blind trial. Phytomedicine 1997;4:101-4.