5 supplements to support your immune system  

woman sitting on couch feeling ill

Fall and winter can be tough on your immune system. If you aren’t looking to spend the chillier months holed up in bed with a box of Kleenex and a dehumidifier (ahem, most of us), you’re likely seeking out ways to bolster your body’s defenses. But before you go filling your vitamin cabinet with zinc, vitamin C and other immunity favorites- you may want to consider if these supplements are actually going to give you the support you’re looking for. Lucky for you, we’ve taken a deep dive into the research to find out which supplements are worth their salt and which ones are something to sneeze at.   

1. Zinc: immune system standout   

When it comes to your immune system, zinc certainly has an important job to do. Zinc is needed to produce your immune cells, promote wound healing and keep your metabolism going. With all of its important duties, it’s no wonder zinc is a favorite among researchers.  

The research 

The science tells us that if you’re zinc deficient, you’re going to have a harder time fighting off infections. About 17.3% of people across the globe are at risk of zinc deficiency. People with digestive disorders, those who are pregnant, and vegans and vegetarians are more likely to be deficient. 

If you’re not deficient though- should you take zinc to ward off a cold? The answer is a little unclear. A bunch of medium sized studies noticed that people who took a zinc lozenge when they had a cold felt less sick than those who didn’t take a zinc lozenge. The doses used in each of the studies were inconsistent, so we will have to wait and see if researchers can home in on what dose, if any, is most effective.  

Takeaway: If you’re healthy and have a balanced diet, taking a zinc supplement won’t save you any tissue boxes. Chat with your doc about trying a zinc lozenge next time you come down with the sniffles. It may be your best bet.   

2. Vitamin C coming to your defenses  

If you’ve ever needed to power through a head cold, chances are you’ve tried guzzling down a mega-dose of vitamin C. It’s a water-soluble vitamin, meaning it’s not stored in your body and any excess is peed out, so your body relies on your diet for a steady supply.  

The research 

Vitamin C is an immune system superstar- it’s needed for wound healing, helps your body produce immune cells, and is also needed to keep your cells healthy. If you eat fruits and vegetables regularly, you likely aren’t going to benefit from a vitamin C supplement. But if you’re an endurance athlete, you might benefit from a little extra vitamin C to help you combat some of the stress caused by intense exercise. Scientists are still working on that theory though. Until then, chow down on those vitamin C rich foods like strawberries and red peppers and when you start to get a little phlegmy, an extra glass of OJ won’t hurt!    

Takeaway: If you eat your fruits and veggies, you probably won’t benefit from a vitamin C supplement. Really large doses of vitamin C don’t have any proven benefit but if you’re an endurance athlete you could consider supplementing, though more research is needed.  

3. Probiotics for gut and immune health  

You might be surprised to learn that 70% of your immune system lives in your gut. Your intestines are lined with trillions of tiny bacteria that not only act as a physical barrier to ward off nasty invaders, but those bacteria also communicate with your immune cells and may tell them when to get to work and when to take a rest.  

The research 

Given the role your gut plays in your immune system, it makes sense that a probiotic with billions of beneficial bacteria might help support your immunity. Unfortunately, it’s not so simple. If you’ve shopped for a probiotic lately, you’ve probably noticed there are tons of different strains, each with their own specialty. So which strains help your immune system the most? Well, we don’t really know yet. But Lactobacillus and Bifidobacterium are at the top of the list. So if you’re shopping for a probiotic to help out your immunity- look for one with either of those two strains,  

Takeaway: A healthy gut is key to a healthy immune system. We’re still not sure if supplementing with a probiotic can improve your immune system, but two strains, Lactobacillus and Bifidobacterium have stood out in the research as potentially immune supporting.  

4. Spirulina: rich in antioxidants   

What’s bad for your beach day but good for your breakfast smoothie? Spirulina of course. It’s a type of blue green algae that can be naturally found in lakes, ponds and streams but is also harvested and used as a nutritional supplement. It’s known for antioxidant qualities, contains a whole profile of vitamins and minerals and may even help support your immune system health. 

The research 

Like vitamin C, spirulina’s immune supporting abilities may only lend themselves to a specific population- endurance athletes. High intensity and high volume exercises can weaken your immune system, but spirulina might help negate those effects, according to one small study.  

Takeaway: Unless you’re an athlete and doing intense daily exercise, your immune system probably isn’t going to benefit from taking spirulina. That doesn’t mean it’s not a great addition to your supplement routine though- spirulina contains a lot of great vitamins and minerals.  

5. Vitamin D: the sunshine vitamin 

Come cold and flu season, the spotlight is on the sunshine vitamin. We know that your immune cells need vitamin D in order to function, but scientists aren’t really sure exactly how vitamin D works with those immune cells. 

The research 

A few studies have noted a link between Vitamin D deficiency and risk for severe symptoms from viruses like the flu. If you’re not deficient in vitamin D though, adding a supplement to your routine won’t keep you from getting sick. You can get a simple blood test to check your vitamin D status, and if it ends up being on the low side, it might be a good idea to supplement, especially during winter months when it’s harder for your body to get vitamin D from sunlight.  

Takeaway: If you’re one of the 24% of people with low vitamin D, your immune system might have a harder time fighting off infections. If your vitamin D is in a healthy range, supplementing won’t give you any superpowers.  

About Yaquelin    

Yaquelin is a Registered Dietitian Nutritionist. Her passion is helping others live healthier and happier lives. She enjoys learning about new supplements, working out and baking sweet treats. 

Do you have questions about supplements? Reach out to one of our experts, or take Persona’s free nutrition assessment, and learn exactly what you need to take your wellness to the next level.     

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. As with any dietary supplement, you should advise your healthcare practitioner of the use of this product. 

This information is not intended as a substitute for the advice provided by your physician or other healthcare professional, or any information contained on or in any product label or packaging. Do not use the information from this article for diagnosing or treating a health problem or disease, or prescribing medication or other treatment. Always speak with your physician or other healthcare professional before taking any medication or nutritional, herbal, or homeopathic supplement, or using any treatment for a health problem. If you have or suspect that you have a medical problem, contact your health care provider promptly. Do not disregard professional medical advice or delay in seeking professional advice because of something you have read in this article.    


  1. Wang MX, Win SS, Pang J. Zinc Supplementation Reduces Common Cold Duration among Healthy Adults: A Systematic Review of Randomized Controlled Trials with Micronutrients Supplementation. Am J Trop Med Hyg. 2020;103(1):86-99. doi:10.4269/ajtmh.19-0718 
  2. Zhang Y, Zhang Y, Wu W. Effects on Spirulina Supplementation on Immune Cells’ Parameters of Elite College Athletes. Nutrients. 2022; 20 (14) 4346 10.3390/nu14204346   
  3. Vlasova AN, Kandasamy S, Chattha KS, Rajashekara G, Saif LJ. Comparison of probiotic lactobacilli and bifidobacteria effects, immune responses and rotavirus vaccines and infection in different host species. Vet Immunol Immunopathol. 2016;172:72-84. 
  4. Ao T, Kikiuta J, Ishii M. The Effects of Vitamin D on Immune System and Inflammatory Diseases Biomolecules 2021, 11(11), 1624; https://doi.org/10.3390/biom11111624

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