The Best Immune-Supporting Supplements Available in 2021

Table of Contents:

  1. What is the Immune System and Why is it Important?
  2. What Factors Can Suppress the Immune System?
  3. The importance of Supplementation for Optimal Immune System Function
  4. What are Some of the Top Immune System Supplements Available? 
  5. What is Cell Block? 
  6. How do the Ingredients in Cell Block Support Immune Health? 
  7. How do Vitamin A and Vitamin D3 Work Synergistically in Cell Block? 
  8. The Bottom Line

Cultivating a strong immune system is at the forefront of many people’s minds these days. While eating a healthy diet, exercising, de-stressing, and getting adequate sleep will always be the mainstays of a healthy immune system, research shows that taking certain vitamins will help build a strong foundation. 

In this article, we’ll be exploring the purpose of your immune system and how you can best support it. We’ll be sharing the specific ingredients to look for in immune-boosting supplements, as well as our top supplement choice based on extensive research. Let’s dig in! 

 What is the Immune System and Why is it Important? 

A strong immune system is the key to preventing illness and staying healthy. This complex network of cells and proteins is your first line of defense against infection. Without an immune system, we would have no way to fight harmful microbes that enter our bodies or harmful changes that occur inside our bodies. The main tasks of the immune system include: 

  1. Fighting disease-causing germs (pathogens) such as bacteria, viruses, parasites, and fungi, and removing them from the body. 

  2. Recognizing and neutralizing harmful substances from the environment.

  3. Fighting disease-causing changes in the body.

Your immune system keeps a record of every germ it has ever defeated so it can recognize and destroy it quickly if it enters your body again. When your immune system is strong, harmful microbes don’t stand a chance, but when it’s not, you become much more vulnerable to illness. 


What Factors Can Suppress the Immune System? 

There are a number of factors that can prevent our immune systems from working optimally. These include: 

Older age:

As we age, our internal organs become less efficient. Immune-related organs like the thymus and bone marrow produce fewer immune cells, which are needed to fight off infections. Aging is also associated with micronutrient deficiencies, which can further decrease immune function.

Environmental toxins:

Things like air pollution, cigarette smoke, alcohol, and pesticides can impair or suppress the normal activity of immune cells. 

Excess weight:

Obesity is associated with low-grade chronic inflammation. Although more studies need to be done, early research has identified obesity as an independent risk factor for the influenza virus, possibly due to the impaired function of T-cells (a type of white blood cell). 

Poor diet:

A diet lacking in one or more nutrients can impair the production and activity of immune cells and antibodies. 

Chronic diseases:

Autoimmune and immunodeficiency disorders attack and potentially disable immune cells. 

Chronic mental stress:

Stress releases hormones like cortisol that suppress the immune system.

Lack of sleep and rest:

Sleep is a time of healing and repair, during which a type of cytokine is released that fights infection. Too little sleep lowers the amount of these cytokines and other immune cells.

The Importance of Supplementation for Optimal Immune System Function

Due to the above-mentioned factors, our immune systems don’t always work as well as we would hope they would. This is where an immune-supporting supplement comes in. Now, you might be thinking, “Can’t I just get all necessary immune-boosting nutrients from food?” In a perfect world, we likely could get all of our immune-boosting nutrients from the foods we eat. 

The reality is, this is nearly impossible due to several factors such as poor diet, genetic variations, dietary restrictions, unavailability of certain foods, busy schedules, and personal preferences. Proper supplementation can cover the nutritional blind spots in your diet, provide you with higher levels of nutrients than you could get from food alone, and add extra support in the face of factors like chronic stress or a lack of sleep. 

Research has long shown that the immune system can only function when sufficient nutrients are available. Adequate amounts are essential to ensure the proper function of immune cells. As we just discussed, there are many reasons why we might not be getting adequate amounts of the nutrients the immune system needs to function optimally. By taking supplements with immune-boosting nutrients, you’re ensuring that your body has enough of what it needs to fight off harmful invaders.

Taking a supplement isn’t really about “boosting” your immune system—it’s about making it a well-oiled machine that works appropriately when needed. You don’t want your immune system to be over-functioning, as this can potentially create a cytokine storm, but you don’t want it to underperform either. 

What are some of the top immune system supplements available? 

In researching online, you’re likely to find many supplements geared towards boosting the immune system. Let’s take a look at some of the available options: 

Nature’s Bounty Immune 24 Hour+:

This supplement contains a dose of vitamin C, which is said to stay in your white blood cells for 24 or more hours. It also contains zinc, vitamin D, Vitamin A, elderberry, and Echinacea. 

BioSchwartz Immunity Boost:

This formula contains 17 natural ingredients including vitamin C, zinc, elderberry, and Echinacea. It’s said to support the respiratory system and immune cell function.

Here Comes the Sun by Hum:

This supplement is vitamin D3, offering a 2,000 IU dose per day. 


This fizzy supplement is a go-to for many people when they have the sniffles. It contains 1000mg of vitamin C, plus other boosters like vitamin D and zinc. 

Garden of Life Vitamin Code Raw Zinc:

This supplement provides a good dose of raw zinc in whole-food form, making it easier to absorb. The formula also contains vitamin C. 

Nature’s Way Sambucus Black Elderberry Gummies: 

Elderberries are said to shorten colds and reduce symptoms. People often take elderberry for preventative measures, too. These tasty gummies contain elderberry, vitamin C, and zinc. 

Source Naturals Wellness Formula:

This is a popular immune-support formula that contains 30 ingredients—a mix of antioxidants, herbal extracts, vitamins, and minerals. The tricky thing about this supplement is that it requires you to take up to six capsules every three hours. 

Gaia Herbs Quick Defense:

This herbal remedy offers Echinacea, elderberry, and ginger to help support your body’s natural defenses.

While all of these supplements likely offer some benefit, some reviews say that the formulas don’t live up to their claims. Additionally, most of these supplements contain more ingredients than necessary. When it comes to effective immune-supporting supplements, having dozens of ingredients doesn’t necessarily make a supplement more effective. What really matters is including research-backed ingredients in the right ratios and at the right dosages, which brings us to our top supplement choice: Cell Block. 


What is Cell Block? 

Clarke Bioscience’s Cell Block is a high-dose combination of vitamin A and vitamin D3 that’s specifically formulated to support your immune health. This powerful formula was created by world-renowned neuroscientist, Dr. Lewis Clarke, who has over 30 years of experience in the medical field. 

Each box of Cell Block delivers a potent immune blend containing 700,000 IU of vitamin A and 100,000 IU of vitamin D. This supplement is designed to be taken only once per month on two back-to-back days. Because it is not designed to be taken daily, this saves a lot of hassle, as you don’t have to remember to take capsules every day.  

How Do the Ingredients in Cell Block Support Immune Health? 

 Let’s take a look at how Cell Block’s two powerhouse ingredients can support your immune health: 

Vitamin D3

Overwhelming evidence supports vitamin D’s immune health benefits. A 2011 double-blind placebo study (the gold standard of medical research studies) found that a therapeutic dose of vitamin D resulted in a 42% lower incidence of common seasonal maladies. More recently, researchers from Trinity College in Dublin, Ireland stated that vitamin D deficiency is suggested to play an important role in the severity of more life-threatening infections. 

According to a 2013 study, vitamin D deficiency should be addressed by eating foods that naturally contain vitamin D, getting sensible sun exposure, and taking a vitamin D supplement.

Research indicates that vitamin D plays an important role in the immune system by: 

  • Supporting upper respiratory health 

  • Supporting the production and activation of T-cells, an important part of the immune system

  • Reducing oxidative stress at a cellular level 

  • Supporting heart health

Vitamin A

Vitamin A is known as an anti-inflammation vitamin because of its critical role in enhancing immune function. Research shows that vitamin A is involved in the development of the immune system and plays a regulatory role in cellular immune responses. 

Studies show that a deficiency in vitamin A can increase your susceptibility to infections and delay your recovery when you get sick.  In fact, in countries where medical care is not as prevalent, correcting vitamin A deficiency in children has been shown to decrease the risk of unwanted affects from common adolescent maladies. 

Research indicates that vitamin A plays an important role in the immune system by: 

  • Increasing the number of T and B lymphocytes (immune cells). 

  • Supporting the production of the immunoglobulin, IgA, which coats our mucus epithelium in our noses, lungs, and GI tract.

  • Encouraging cell growth and reproduction 

  • Fighting free radical damage 

  • Supporting the production and function of white blood cells

  • Supporting heart health 

How do Vitamin A and Vitamin D3 Work Synergistically in Cell Block? 

While vitamin D3 and vitamin A offer many immune supporting benefits individually, there’s also a major benefit to taking these two vitamins together. Studies show that when taken simultaneously, vitamin D proteins pair up with vitamin A proteins in what is called a heterodimer (another word for a protein composed of two polypeptide chains). This complex structure then binds to a vitamin D receptor, which causes the CAMP gene in immune cells to secrete defensin, cathelicidin, and LL-37—all of which support the production of more immune cells. 

Translation? While both of these vitamins are beneficial on their own, when taken together, vitamin D and vitamin A provide unrivaled, powerful immune system support. According to the creator of this formula, Dr. Lewis Clarke, when paired together, vitamin A and vitamin D become a tag team that supports immune system function and upper respiratory health. 

The Bottom Line

Maintaining a well-functioning immune system is essential for your overall health. However, due to a number of factors, our immune systems aren’t always working optimally, potentially opening the door to illnesses. Taking a targeted immune supplement is a great way to ensure that your immune system is getting the essential nutrients it needs to function properly. Cell Block is the top immune-support supplement on the market, offering a potent dose of vitamin D3 and vitamin A. Requiring only two doses a month, supporting your immune system has never been easier with Cell Block.