You’ve had your flu shot and are doing your best to get enough rest and stay healthy. Wondering if there are other ways to get a leg up on cold and flu season? Luckily, there are additional steps you can take to boost your immunity through supplementation.

Here are a few natural immune system boosters you may want to consider.

Andrographis

Though andrographis (aka Indian ginseng) has been used to prevent and treat cold and flu symptoms for ages, this herbal supplement is widely available in parts of Europe but can be somewhat hard to find in the U.S.

In one double-blind study, the incidence of subjects who caught a cold while taking andrographis during the winter season was significantly less than subjects who were randomized to the placebo group.

In another study, andrographis reduced the severity of cold symptoms by the second day of treatment when subjects took 1,200 milligrams/day. By day four, symptoms were even further improved.

Try: Nature’s Way Andrographis Capsules

Elderberry

There’s evidence that the extract from the dark purple berries of the Elder tree could be useful in fighting cold and flu symptoms.

Results from a study published in 2004 confirmed that adults suffering from flu symptoms who took elderberry syrup experienced symptom relief up to four days earlier than subjects who took a placebo.

While larger studies are needed to confirm the results, elderberry extract seems to be both a safe and effective way to naturally treat and prevent influenza.

Try: Gaia Herbs Organic Black Elderberry Syrup

Echinacea

Although some studies have found no evidence echinacea works to treat symptoms of the common cold, others show it can reduce the length and severity of colds over that of a placebo.

Some of the conflicting results may be due to the different species of echinacea used across clinical trials. The results of one large study published in Evidence-Based Complementary and Alternative Medicine suggested positive results from Echinacea purpurea.

Try: Simple Truth® Echinacea Purpurea Capsules

In addition to supplements, a healthy lifestyle goes a long way in reducing your risk of getting sick. Remember to wash your hands often during cold and flu system, find ways to destress and exercise regularly.