Vitamins and supplements can offer certain health benefits for some people — but unfortunately, buzzwords, false claims, and a lack of regulation often make it difficult to find an option that's effective and safe. The best vitamins and supplements to boost the immune system contain certain key ingredients backed by science but leave out unwanted additives. The options aren't always easy to narrow down, so New York-based research neuroscientist Nicole Avena, Ph.D., Ontario-based naturopathic doctor Yelena Deshko, N.D., and Jacksonville, Florida-based Anthony Capasso, M.D., and consultant to PureLife Organics, weighed in to share some of their favorite immune-boosting ingredients and offer advice for shopping for supplements in general.
To choose the best active for you, consider your lifestyle and needs. "Zinc helps to fight off invading bacteria and viruses," Dr. Capasso explains in an email to Mic, so it may help if you're often exposed to germs. He describes immune defense-boosting vitamin C as "a potent antioxidant," which can scavenge free radicals that result from exposure to pollution and harmful chemicals. Vitamin D is important because it "regulates multiple functions in the body from brain health to bone health," according to Dr. Capasso — and a deficiency of vitamin D often comes from lack of sunlight. He explains that B vitamins "are synthesized from the bacteria and yeast in our gut," but since we can't make these vitamins without the right foods, they're usually lacking in an unbalanced diet. Stress, poor sleep quality, smoking, and alcohol can also weaken the immune system as a whole.
If you're looking for an immune-boosting supplement that can also promote relaxation, try L-theanine. Deshko writes, "Research suggests that L-theanine, a compound found in green tea, can help T cells (a type of immune cell) defend against invading bacteria," Deshko writes — adding that the compound might help you relax, too.
And when it comes to botanical extracts, consider aged garlic and elderberry, especially during cold and flu season. According to Deshko, aged garlic extract "may enhance immune cell function and may be partly responsible for the reduced severity of colds and flu reported by participants of one study." Dr. Avena also notes that "elderberry has potential benefits in reducing recovery time after colds and the flu."
Of course, it's always a good idea to consult a medical professional before taking any new vitamins or supplements. According to Dr. Capasso, you may want to consider testing for vitamin deficiencies if you follow a limited diet, regularly consume alcohol, have digestive issues or celiac disease, or take a lot of medications.
As you're shopping, you'll also want to keep an eye out for unwanted fillers to ensure you're getting a quality product. "Many brands of supplements contain artificial colors, flavors, and other various unhealthy ingredients," according to Deshko.
With all of that in mind, here are some of the best vitamins and supplements for boosting your immune system.
The zinc & vitamin C supplement
"Vitamin C is perhaps the most well-known vitamin for supporting the immune system," Deshko explains. Studies have shown that zinc affects different parts of the immune system. She adds that "zinc is known to play a central role in the immune system, and zinc-deficient persons experience increased susceptibility to a variety of pathogens."
According to Dr. Avena, "Frunutta Zinc + Vitamin C is great because it is a sublingual (dissolves right under your tongue)," so it's especially easy to take. It also contains just the vitamins — no fillers (though, it does contain milk). The brand was founded by physicians and produces their supplements in an FDA-registered facility that meets strict quality standards.
- Amount per serving: 5 mg zinc, 15 mg vitamin C
The well-rounded immune supplement
This Immune Boost supplement from NutraChamps offers a combination of ingredients you'll find in other supplements on this list, including vitamin C, vitamin D, zinc, and elderberry. It also contains selenium and probiotics. "Selenium and probiotics are thought to help improve the immune system," Dr. Avena writes. "Selenium is a nutrient that can be used as an antioxidant and probiotics cultivate healthy gut bacteria which can help improve overall health."
The vegan-friendly capsules are made without gluten, corn, nuts, soy, or sugar, and they're produced in a facility that is Current Good Manufacturing Practice (GMP) approved.
- Amount per serving: 1000 mg vitamin C, 125 mcg vitamin D3, 15 mg zinc, 30 mcg selenium, 300 mg herbal defense blend, 100 mg mushroom blend, 1 billion CFU probiotic blend
The vitamin D supplement
According to Deshko, "Vitamin D has numerous effects on cells within the immune system. Results of studies looking at potential benefits of administering vitamin D to decrease infection have not been conclusive, though promising." Dr. Avena elaborates: "Vitamin D helps to assure that proper proteins are synthesized in the innate immune system. There are many receptors in immune cells for vitamin D that either block or trigger certain functions."
Regarding supplementation, Dr. Avena recommends Vitafusion D3, which comes in a gummy form that's "easy to take." They taste like peaches and berries, but they skip the high-fructose corn syrup, artificial sweeteners, gluten, dairy, and synthetic dyes. They're also designed for efficient absorption to better support immunity.
- Amount per serving: 50 mcg vitamin D
The elderberry gummies
According to Dr. Avena, elderberry can speed up recovery from colds and the flu "by activating the body’s immune response, increasing antibody and immune cell production." And elderberry may even serve as a preventative measure against illness. Deshko writes, "Sambucus nigra L. (elderberry) extracts have some evidence showing antiviral properties, especially against different strains of influenza virus." She explains, "In addition to direct anti-viral effects, elderberry is known to contain high levels of antioxidants, which may contribute to its immune stimulating and anti-inflammatory effects."
These elderberry gummies from Nature's Way have more than 80,000 positive reviews on Amazon and an overall rating of 4.8 stars. The formula is tested for bioavailability (meaning your body can more easily absorb its nutrients), gently extracted to ensure potency, and made without common allergens like wheat, eggs, dairy, peanuts, and artificial colors. It also includes vitamin C and zinc.
- Amount per serving: 50 mg black elderberry, 90 mg vitamin C, 7.5 mg zinc
The garlic supplement
"Garlic (Allium s.), a member of the onion family, contains numerous compounds that have the potential to influence immunity," Deshko explains. This vegan Think Remedy aged garlic supplement is made without fillers and produced in a GMP-certified facility. It's highly rated on Amazon, too.
While reviewers have claimed that it does have a smell and taste, many have also confirmed that they don't linger. "No after taste or garlic breath but all the health advantages of garlic," described one reviewer.
- Amount per serving: 800 mg aged black garlic powder, 1.2 mg s-allyl-cysteine
The vitamin B supplement
"Vitamin B6 is known for the role it plays in mediating immune system responses," Dr. Avena writes. "Blood cell proliferation is partially dependent on this vitamin and so is antibody production. There is suggestion as well that vitamin B12 has a part in the function of natural killer cells and other cells in the immune system."
If you're looking to supplement with B vitamins, Garden of Life's Vitamin Code is a good option. For one, it contains vitamins B1, B2, B3, B5, B6, and B12. (According to Dr. Capasso, "We are unable to make B vitamins so we must get them from our diet.") Additionally, the vitamins are derived from raw, whole-food sources and are complemented with probiotics and enzymes to help aid digestion.
- Amount per serving: 5 mg B1, 10 mg B2, 45 mg B3, 45 mg B5, 10 mg B6, 133 mcg B12, 60 mg raw probiotic and enzyme blend
The L-theanine supplement
In addition to fending off bacteria, Deshko explains that L-theanine can offer a "boost of antioxidants and dietary phenols, which inhibit the growth of harmful bacteria in your gut. As a bonus, L-theanine helps promote relaxation and fight anxiety."
L-theanine is commonly found in green tea, but if you prefer a supplement rather than drinking lots of tea, Suntheanine is one of the top-selling L-theanine supplements on Amazon and features L-theanine suspended in virgin coconut oil for easy absorption. Plus, the formula doesn't contain GMOs, gluten, soy, or artificial colors.
- Amount per serving: 200 mg L-theanine
Studies referenced:
Aranow C. (2011). Vitamin D and the immune system. Journal of investigative medicine : the official publication of the American Federation for Clinical Research, https://doi.org/10.2310/JIM.0b013e31821b8755
Barak V, Halperin T, Kalickman I. (2001). The effect of Sambucol, a black elderberry-based, natural product, on the production of human cytokines. Eur Cytokine Netw., https://pubmed.ncbi.nlm.nih.gov/11399518/
Bukowski, J. F., & Percival, S. S. (2008). L-theanine intervention enhances human γδ T lymphocyte function. Nutrition Reviews, https://pubmed.ncbi.nlm.nih.gov/18254876/
Carr, A. C., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, https://doi.org/10.3390/nu9111211
Hoffmann, P. R., & Berry, M. J. (2008). The influence of selenium on immune responses. Molecular Nutrition & Food Research, https://pubmed.ncbi.nlm.nih.gov/18384097/
Mikkelsen, K., & Apostolopoulos, V. (2019). Vitamin B1, B2, B3, B5, and B6 and the Immune System. Nutrition and Immunity, https://link.springer.com/chapter/10.1007%2F978-3-030-16073-9_7
Percival SS. (2016). Aged Garlic Extract Modifies Human Immunity. J Nutr., https://pubmed.ncbi.nlm.nih.gov/26764332/
Rail, L. C., & Meydani, S. N. (2009). Vitamin B6 and Immune Competence. Nutrition Reviews, https://pubmed.ncbi.nlm.nih.gov/8302491/.
Shankar AH, Prasad AS. (1998). Zinc and immune function: the biological basis of altered resistance to infection. Am J Clin Nutr, https://pubmed.ncbi.nlm.nih.gov/9701160/
Tiralongo, E., Wee, S., & Lea, R. (2016). Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients, https://pubmed.ncbi.nlm.nih.gov/27023596/
Williams J; Sergi D; McKune AJ; Georgousopoulou EN; Mellor DD;Naumovski N. (2019). The beneficial health effects of green tea amino acid l-theanine in animal models: Promises and prospects for human trials, https://pubmed.ncbi.nlm.nih.gov/30632212/.
Yan, F., & Polk, D. (2011). Probiotics and immune health. Current Opinion in Gastroenterology, https://pubmed.ncbi.nlm.nih.gov/21897224/
Experts:
Nicole Avena, Ph.D., Assistant Professor of Neuroscience at Mount Sinai School of Medicine and Visiting Professor of Health Psychology at Princeton University
Anthony Capasso, M.D. and consultant to PureLife Organics
Yelena Deshko, N.D., Naturopathic Doctor at Timeless Health Clinic
