Skip to content

The Best Vitamins for Immunity, Say Pharmacists

Four vitamins that can help keep your immune system strong and healthy. 

Every day you're exposed to something that can potentially make you sick. From bacteria to viruses to fungi, the world is full of things that cause disease and infections, but your immune system fights hard every second of the day to protect you from illness. So taking care of your body's defense mechanism is essential to staying healthy. Lifestyle choices like not smoking, getting 7-9 hours of quality sleep a night, maintaining a healthy weight and eating a well balanced diet that includes fruits and vegetables builds a strong immune system. But vitamins can also help, according to Raja Sannidhi PharmD with Capitol Drugs who tells us, "Immunity health is very important because it is your first line of defense against infections. Vitamins are also natural. These are fundamental elements that are found in food. We take vitamins because sometimes we don't get the required amounts from our diet." Please consult your physician for medical advice before taking vitamins. Many can have interactions with other medications and pose health risks so do your research and speak with your doctor. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


How the Immune System Works


The National Library of Medicine explains, "The immune system has a vital role: It protects your body from harmful substances, germs and cell changes that could make you ill. It is made up of various organs, cells and proteins. As long as your immune system is running smoothly, you don't notice that it's there. But if it stops working properly – because it's weak or can't fight particularly aggressive germs – you get ill. Germs that your body has never encountered before are also likely to make you ill. Some germs will only make you ill the first time you come into contact with them. These include childhood diseases like chickenpox."


Vitamin C


Dr. Sannidhi says, "This is a strong antioxidant that helps with the production of white blood cells. White blood cells are needed to fight infections."

The Mayo Clinic states, "When taken at appropriate doses, oral vitamin C supplements are generally considered safe. Taking too much vitamin C can cause side effects, including:

  • Nausea, vomiting and diarrhea
  • Heartburn
  • Stomach cramps or bloating
  • Fatigue and sleepiness, or sometimes insomnia
  • Headache
  • Skin flushing

In some people, oral vitamin C supplements can cause kidney stones, especially when taken in high doses. Long-term use of oral vitamin C supplements over 2,000 milligrams a day increases the risk of significant side effects."



Vitamin C and Zinc Lozenges, food supplement

"Zinc helps repair wounds, damaged tissues and also aids in the production of white blood cells," Dr. Sannidhi explains. 

The Mayo Clinic finds zinc to be relatively safe, but warns of certain side effects.  "Oral zinc can cause:

  • Indigestion
  • Diarrhea
  • Headache
  • Nausea
  • Vomiting

When oral zinc is taken long term and in high doses it can cause copper deficiency. People with low copper levels might experience neurological issues, such as numbness and weakness in the arms and legs. The National Institutes of Health considers 40 mg of zinc a day to be the upper limit dose for adults and 4 mg of zinc a day for infants under age 6 months.

Don't use intranasal zinc. This form of zinc has been linked with the loss of the sense of smell."


NAC (N-acetyl L-cysteine) 


Dr. Sannidhi tells us, "This helps in live and kidney detoxification. This is also used for respiratory health. In the body it gets converted to glutathione which helps as well."

Mount Sinai recommends, "Because of the potential for side effects and interactions with medications, take dietary supplements only under the supervision of a knowledgeable health care provider.

Toxic forms of cysteine that should be avoided include:

  • D-cysteine
  • D-cystine
  • 5-methyl cysteine

NAC may raise levels of homocysteine, an amino acid that is associated with heart disease. Be sure to have your doctor check your homocysteine level if you are taking NAC. Very high doses (more than 7 grams) of cysteine may be toxic to human cells and may even lead to death. Taking NAC by mouth may cause nausea, vomiting, and diarrhea. Intravenous administration of 

NAC to treat acetaminophen poisoning may cause severe allergic reactions, including:

  • Angioedema
  • Swelling of the soft tissue just beneath the skin, including the face, lips, and around the eyes
  • Anaphylaxis, a life-threatening allergic reaction

People with cystinuria, a kidney condition in which too much cysteine is lost in the urine, should not take cysteine supplements. When inhaled into the lungs, NAC may cause tightness in the chest, numbness of the mouth, runny nose, and drowsiness. It may make asthma symptoms worse. People with asthma who are taking NAC should be watched closely by their doctors." 


Andrographis (Herb)


Dr. Sannidhi says, "It is an auto immune modulator which has anti-inflammatory properties and helps with respiratory illnesses."


Heather Newgen
Heather Newgen has two decades of experience reporting and writing about health, fitness, entertainment and travel. Heather currently freelances for several publications. Read more about Heather
Filed Under