The Immune Boosting Supplement Our Doctors Love

Kelly Candela, MS, RD
Health Coach
Medically Reviewed
April 2, 2020

There’s never been a better time to focus on supporting your immune system , and the medical team at Parsley Health has a favorite pharmaceutical-grade supplement they turn to and recommend to many members when the dreaded first signs of cold or flu appear or when traveling. And now, we’re bringing it to you: Introducing: Body Guard .

Body Guard joins our suite of Parsley Health supplements . It’s an immune-boosting supplement that helps nip a pesky cold in the bud before it even has the chance to fully surface. It can also be used when you have had recent exposure to friends or family sick with a cold or flu, to help shorten the duration of a cold, or when you’re feeling run down from stress. With its powerful combination of key vitamins, nutrients, and botanical extracts studied to strengthen the body’s immune response, there’s nothing not to love about this pharmaceutical grade formula. Even the strongest and healthiest of us out there need a Body Guard sometimes. Learn more about what’s inside and how to give your immune system some TLC.

How to give your immune system extra support

Your immune system is always working to keep you healthy. It comes to the rescue when you’ve been exposed to a harmful pathogen or foreign invader—like those germs you accidentally inhaled from a coworker’s cough. In order for the immune system’s defense to work optimally, it requires specific nutrients to properly respond to immune challenges that arise. These are the research-backed ingredients in Body Guard that support your immune function. Let’s walk you through the lineup:

Vitamin A

Vitamin A is anti-inflammatory and also plays a critical role in enhancing immune function. Specifically, vitamin A is involved in the creation of certain immune cells, including B- and T-cells , which carry out essential functions such as helping to kill virus-infected cells in the body and binding to toxins. Deficiency in vitamin A has been linked to increased levels of pro-inflammatory molecules and diminished immune response. Studies have shown that vitamin A has a therapeutic effect in the treatment of various infectious diseases such as pneumonia , measles , and tuberculosis .

Vitamin C

Vitamin C helps to support the production of white blood cells which are the cells of the immune system responsible for protecting us against pathogens. On top of that, vitamin C acts as an antioxidant, protecting these disease-fighting white blood cells against damage by free radicals . Studies have linked inadequate vitamin C levels to longer duration of sickness; individuals who suffer from illnesses such as pneumonia tend to have low vitamin C levels , and those given vitamin C supplements while sick have quicker overall recovery time .

Pantothenic Acid

Despite its name, pantothenic acid is part of the vitamin B family and is also known as vitamin B5. This water-soluble b-vitamin plays a direct role in helping the body to create antibodies . Antibodies , also known as immunoglobulins, are Y-shaped proteins that are produced by the immune system to disarm harmful invaders from wreaking havoc—and illness—on the body. The more antibodies that are made, the quicker the body can heal from both internal and external injury. Adequate levels of pantothenic acid levels are also crucial for supporting immune system energy and healthy white blood cell production.


Zinc is a mineral that affects multiple aspects of the immune system , from the barrier of the skin to the regulation of lymphocytes, a type of white blood cell. Specifically, zinc works in conjunction with vitamin A to support immune function and is necessary for proper cell signaling. Without sufficient amounts of zinc present in the body, the immune response slows. In concentrated amounts, zinc can help enhance immunity by supporting a variety of key immune system players including T-cells, natural killer cell activity, macrophage function, and antibody production.


Astragalus (Astragalus membranaceous) is a plant native to Asia that is most known for its use in traditional Chinese medicine as an immune-boosting, anti-inflammatory remedy. The active plant compounds present in astragalus may support immune function by increasing the body’s production of white blood cells . Although more evidence is needed, some studies have shown that astragalus can help fight viral infections and cold symptoms and specifically support the immune system by boosting T-dependent antigens, lymphokine-activated killer (LAK) cells, and macrophage activity.


Similar to astragalus, black elderberry (Sambucas nigra) has long been used as an ancient immune remedy around the world. You’re likely to have seen elderberry syrup, cough drops, or tinctures as a cold or flu remedy at your local health store. The berries and flowers of elderberry are packed with potent flavonoid antioxidants called anthocyanins that support immunity by decreasing the generation of reactive oxygen species, unstable molecules that can form in the body. Mechanistically, elderberry works by enhancing the potential of immune cells to destroy foreign invaders and supports the production of healthy cytokines, the small molecules that assist in cell-to-cell signaling of the immune response. Black elderberry extract has been shown to reduce the duration and severity of the flu and associated cold-like symptoms including fever, headache, muscle aches, and nasal congestion.


Andrographis (Andrographis paniculata) is one of the most popular medicinal plants used traditionally for the treatment of diseases ranging from cancer and diabetes to bronchitis and influenza. This native South Asian plant possesses a wide variety of anti-inflammatory, antiviral, antioxidant, and antibacterial properties. In a study from 2017 , researchers found that andrographis proved to be beneficial for relieving symptoms of upper respiratory tract infections. Andrographis has also been associated with decreased duration of cough, sore throat, and sick days compared to those who did not take it while sick.


Echinacea is a plant best known as an over-the-counter herbal remedy for the common cold or flu. This native United States plant is loaded with antioxidants, such as flavonoids, cichoric acid and rosmarinic acid . The powerful compounds present in echinacea help to support immunity by enhancing specific immune cell counts, specifically boosting production of leukocytes and granulocytes. Echinacea has been shown to help accelerate recovery from illness , lower the risk of developing colds by greater than 50%, and shorten the duration of colds by one and a half days.


L-lysine is an essential amino acid that holds special power in helping boost immune function. Lysine has been shown to improve wound healing by increasing the body’s natural production of collagen. Additionally, lysine has been studied to significantly increase immune-specific complexes such as T-cells and various immunoglobulins—all of which serve key functions in fighting infection.

How to use Body Guard

For immediate immune support, our Parsley Health doctors recommend taking two capsules three times per day for about one week while feeling under the weather. Generally, if you do not improve within 7-10 days or if symptoms continue to worsen, we recommend visiting your doctor. For immune maintenance or proactive protection, just two capsules per day should suffice to ward off sickness. Despite the overall safety of Body Guard, we do recommend consulting with your personal physician before starting any new dietary supplements to ensure all ingredients are well suited for you.

NOTE: We encourage anyone with signs of a respiratory infection or COVID-19 (fever, dry cough, and/ or shortness of breath) to contact their primary care physician for guidance through a virtual visit or by phone. If you develop severe symptoms (such as but not limited to persistent fever >102, difficulty breathing at rest, or become confused or difficult to arouse) or are in the high-risk groups outlined above and develop shortness of breath, call 911 or go to the nearest emergency room after calling ahead for safe arrival instructions.

Kelly Candela, MS, RD
Health Coach

Kelly Candela is a registered Dietitian Nutritionist with six years of experience in the health and wellness field, four of which have been spent right here at Parsley Health supporting members with everything from gut issues and autoimmune disease to cardiometabolic health concerns and fertility. She holds a Master's of Science in Nutrition from one of the leading science-based natural medicine schools in the country, Bastyr University, and completed her dietetic internship at Sea Mar Community Health Center in Seattle, WA.

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