Supplements That Actually Work for Immunity

Just like that, cold and flu season is once again upon us. Scrolling the aisles of the drug store, there are countless supplements marketed as immune system boosters. Many of them are expensive, some contain fillers you want to avoid and others don’t even have high enough quantities of nutrients to do much. So with that in mind, we wanted to discuss which supplements actually work for immunity.

How to Strengthen Your Immune System

Firstly, it’s important to point out that you can’t really out-supplement an unhealthy diet and lifestyle. Whether or not you lead a generally healthy lifestyle will play a more important role in whether or not you get sick. In fact, we’ve covered this topic several times at HEAL:

How You Can Skip Cold & Flu Season

Natural Cold & Flu Remedies That Actually Work

So before we dive into supplements that work for immunity, here are some healthy-living strategies you can implement today so that you give your immune system what it needs to function well:

  • Don't smoke
  • Eat a diet high in fruits and vegetables
  • Exercise regularly
  • If you drink alcohol, drink only in moderation
  • Get adequate sleep (aim for 8 hours)
  • Take steps to avoid infection, such as washing your hands (especially around sick people) and cooking meats thoroughly
  • Try to minimize stress

If you give your immune system the building blocks it needs, you should be able to ward off most colds, flus and infections.

Supplements That Work For Immunity

One thing the above factors have in common is that they can deplete your immune system of many of the nutrients it needs to function optimally. For example, vitamin C is quickly depleted during times of stress, potentially making you more susceptible to getting sick. There are supplements you can take during cold & flu season, or when you’re at a great risk of getting sick, that actually work for immunity.

*We’ve included the names of the brands we like directly in this post - you just have to follow the links, create a free Fullscript account if you haven't already, and then search for the product name in our dispensary to get them.

Vitamin C

Vitamin C deficiency results in impaired immunity and greater susceptibility of infections. Though deficiency is less common in developed countries, many lifestyle factors like smoking, stress, and not eating enough fruits and vegetables deplete vitamin C levels and increase your daily needs. Therefore, if you fit into this category or feel you are getting sick, supplementing with Vitamin C may be helpful. Vitamin C administered in doses of 6-8g/day has also been shown to reduce the duration of colds.

We like: Designs for Health Liposomal Vitamin C. Liposomal vitamin C is more expensive but it’s the most readily absorbed form of vitamin C so you only need to take a few doses a day.

Vitamin D

Studies show that the lower your vitamin D levels, the higher your risk of respiratory tract infections and flus. Vitamin D deficiency (under 30ng/mL) is also associated with increased autoimmunity (i.e. arthritis, celiac, Hashimoto’s, diabetes, MS, Graves disease) and greater susceptibility to infection. A study by Stats Canada on vitamin D levels of the Canadian population between 2009-2011 found that about 10% of Canadians were deficient and 32% had insufficient vitamin D levels for bone health (75 ng/mL is considered optimal). Given that vitamin D levels decline in the winter when we are not exposed to as much sunshine, supplementing is a good idea, at least in the winter months.

We like Thorne Vitamin D3/K2 because the K2 helps increase absorbency. Email us if you’d like to purchase this as it’s only available through practitioners.


Zinc is like vitamin C’s mineral cousin; it is one of the key nutrients needed by your immune system. In a 2015 review of 16 studies, the researchers found that zinc (ideally 75mg or more) administered within 24 hours of onset of symptoms reduces the duration of common cold symptoms in healthy people (note that this is well above the amount you should take for general health). Often, taking a few zinc lozenges within the first 24 hours of a cold helps to prevent the onset. 

*Zinc can make you feel nauseous if you take it in high quantities and on an empty stomach, so try to take it with food.

We like: Zinc SAP (zinc picolinate) by Nutritional Fundamentals for Health.


Research on probiotics is rarely black and white. What we do know is that probiotics regulate immune function and protect against pathogens and bacteria in the gastrointestinal tract. Many of the factors listed above (i.e. stress, smoking, low consumption of fruits and veggies, alcohol, etc.) can contribute to a die off of beneficial bacteria, leading to a greater likelihood of getting sick. Supplementing with a probiotic containing lactobacillus and bifidobacterium strains during the winter months, or when you’re at a greater risk of getting sick (i.e. if you are travelling), can support your immune system. Observationally, we have also found that by resolving our client’s digestive health issues, in part by addressing food sensitivities, reinoculating the good bacteria with probiotics, prebiotics and fermented foods, and resolving leaky gut, they no longer get sick as often.

We like:

Genuine Health’s advanced gut health probiotics.

HMF Travel if you travel often.

HMF Forte for long-term immune support.

Getting sick all the time, despite eating well, working out and sleeping well? There are underlying issues like food sensitivities and hormonal imbalances that could be a root cause. Don't hesitate to reach out to see how we can help.

Written by: Natalia Bragagnolo, RHN

Additional Sources:

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