Supplements for colds

It's coming to that time again...

For half your office to be out of action​...

For your training to be rudely interrupted...

For your sleep to go to hell...

Cold and flu season is fast approaching!​

Before we get to the supplements, please heed the most basic piece of advice you already know, but always ignore.

The most simple way to avoid getting sick is to avoid the bacteria that cause the sickness in the first place!

So, wash your hands, avoid touching hand rails and other items in public places where possible, and keep your hands away from your face.

Also, stay away from that one colleague who seems to constantly be sick. You can find a reason to talk to them again in a few months!​

Your next resort will be making sure your nutrition and general lifestyle is sorted. Read my sleep article again, make sure you eat enough protein (it supports immune function)​ and a wide variety of fruits and vegetables.

OK - with all that out of the way, let's get to the supplements!



Garlic is a preventative measure, so you should be taking it throughout cold and flu season to avoid getting sick in the first place.

It works by improving the ability of white blood cells to destroy invaders and upregulates the production of some immune cells (specifically, killer T-cells).

Garlic comes in supplemental form​ - look for aged garlic extract, and take around 800-1000mg in divided doses throughout the day.

You can also just eat it! You'd need 2-3 cloves throughout the day to get the same benefit as the above supplemental dosage, though.​


Zinc is important to immune system function and research has shown effectiveness in reducing the length of illness for infectious diseases like the common cold.

This is also something I'd recommend taking throughout winter, but you need to make sure you don't take too much as it can interfere with the absorption of other minerals such as copper.​

5-10mg per day is a safe low end for zinc supplementation.

Vitamin D

There is a huge variety of benefits from adequate vitamin D levels, but to focus on the immune benefits, vitamin D has solid evidence backing its ability to reduce the risk of catching the flu.

You should regularly check your vitamin D levels with your doctor, but to gain the immune benefits, you'd be aiming for blood levels of between 50-125mol/L or 20-50ng/mL (depending on the units used in your country). Personally, I like to be in the upper half of those ranges (or the 3rd quartile).

There is a study done in Japan that showed that children taking 1200IU of Vitamin D daily were 40% less likely to get the flu during winter. This should be of note for parents who understand how easy it is to get sickness passed on from your kid!

Your daily dose should be tied to your current levels, but a safe bet is 2000-3000​IU per day for adults.



Echinacea supplementation has mixed effects in the literature.

Some evidence seems to point to a reduced risk of infection and reduced length of sickness if taken consistently on a daily basis, but other evidence reports no significant effects.

The dosages used in studies range from 1000mg to 1500mg taken in divided doses daily, so this is a good range to aim for.​


Andrographis supplementation also has unclear effects in the literature.

Some evidence shows reduced length of illness as well as reduced severity of symptoms related to the common cold, but most of the research doesn't actually look at andrographis supplementation as a stand-alone. It's very often paired up with another herb (usually some form of ginseng), so it's difficult to say for sure how effective it is.

Still, based on the current human research, I'd say it's worth trying to get over a cold that's already taken root.

One of the other problems in the research and on the shelves is that there doesn't seem to be a standardised extract concentration of the active ingredient.​ This means dosages will vary quite a lot depending on the quality of the supplement.

Dosages should be ​around 5000mg of standard root extract, or 200mg for a concentrate.

African Geranium

This herb has good evidence for use with acute lung infections, and less convincing use for the common cold.

Still, it can help treat illness involving a bad cough.​

Around 50mg per day split up into even doses is recommended​

So there you have it - the major supplements I'd be looking at to reduce your chances of getting sick or prevent the worst symptoms of the common cold.​

Let us know in the comments if there are any other supplements you might have heard of that you'd like to know about!​

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