When you need some backup, you can turn to several supplements that have demonstrated antiviral properties. Maintaining a healthy immune system with a little support may help keep the bugs at bay. And if you do succumb, key supplements may help reduce the severity of symptoms and/or the length of illness.

A, B, C, and D vitamins

Vitamins A and B6 are important for the development and regulation of the innate immune system. Vitamin C is well known as a cold and flu fighter, but it seems to be less effective for prevention than it is for reducing the severity and duration of colds once we get sick.

When it comes to vitamin D, among those who are deficient, supplementation is consistently associated with benefits to immunity. Daily vitamin D supplementation has been shown to reduce incidence of influenza A in schoolchildren.

Echinacea

Did you know that children catch an average of six to 10 colds or flus every year? When your child catches a cold, starting echinacea as soon as symptoms appear provides the best chance for a beneficial effect. The root of Echinacea purpurea may help lessen symptom severity and shorten the duration of illness.

Elderberry

Elderberry (Sambucus nigra) is a favorite folk medicine for its ability to inhibit viral infection. Packed with nutrients including vitamin C, fiber, and antioxidants that are known to help stimulate your immune system and fight inflammation, elderberries have shown positive effects on the length and severity of flu and common cold symptoms. Elderberries are most often consumed as a syrup, but you can also find them in teas, gummies, lozenges, or pills.

Garlic

Garlic contains a compound called allicin, which has been shown to kill viruses, including rhinovirus and parainfluenza virus. A randomized trial of 120 adults found that aged garlic extract increased T-lymphocytes and NK cells (important immune system defenders) and reduced the severity and duration of cold and flu symptoms.

N-acetylcysteine (NAC)

Glutathione, considered to be the master antioxidant, is responsible for cellular health throughout the body, DNA synthesis and repair, and fine-tuning the innate immune response to infection. Glutathione can be taken as a supplement but is typically expensive. Alternatively, N-acetylcysteine (NAC), a precursor to glutathione in the body, is considered a more affordable option.

Probiotics

Because probiotics function as immune modulators, probiotic supplementation may be a powerful tool against cold and flu viruses. A 2015 Cochrane meta-analysis that evaluated 12 research studies involving 3,720 participants, including children, showed better results in several areas for supplementation with probiotics over placebo, including reducing the number of participants who experienced acute upper respiratory tract infection, as well as infections’ average duration and cold-related school absences.

Zinc

This mineral may be one of the most widely studied for its antiviral effects. It can improve the antiviral response (ability of the innate immune system to resist a virus), inhibit viral replication (slowing down the ability of the virus to grow new versions of itself during the infection process), and reduce related symptoms (sneezing, coughing, fever). Zinc lozenges seem to be particularly effective.