If you want to know what the best (and worst) immune booster supplements are to improve your immune health, get sick less often, and recover faster from illnesses, then you want to read this article.

Key Takeaways

  1. Immune booster supplements work by enhancing your immune system so you get sick less often, stay sick for a shorter period of time, or deal with sickness better.
  2. While Pelargonium sidoides (pelargonium) is very well researched, other immune boosters tend to have mixed evidence. There are many, many options but most have limited human studies.
  3. If you want to boost immunity, make sure you’re nourished and have a good sleep cycle. Beyond that, add a polysaccharide source (like Reishi) and garlic. Keep pelargonium on standby.

I miss the days where I felt invincible.

Hitting the gym, getting a new PR, drinking my protein shake and then heading home with the thought, “Hmm, I could probably tip that smart car. Hell, it would probably bounce off me if I flexed my glutes at the right time.”


Then I studied immunology, and what happens when it fails.

It’s a wonder why us humans are still alive. We’re pretty much a rotting card castle in a storm being held together by week old chewing gum—discount brand.

I mean, we have a highly evolved immune system in our body that isn’t above turning right around and attacking us if we just so happen to eat the wrong food.

Thanks, traitorous scumbags. Why can’t my body have a gulag?

Oh ya, that’s right, cause if it did and I put the immune cells there then the innumerable microscopic threats in my home or the illegal bacterial immigrants living in my colon and on every inch of my skin would kill me in less than a day.


Ultimately this all highlights how necessary it is to at least keep an eye out for good immune health, which thankfully the trifecta of diet, sleep, and exercise should do wonders for. Even then we do get sick sometimes, the immune system isn’t perfect after all, and at these times some supplements can help.

Some supplements.

Seems like half the supplements in existence are argued for being immune boosters for some reason. Immunology is an important field but one that’s so bloody confusing that many people just give up trying to learn it and throw the term “Immune Booster” around willy nilly.

So, might as well give a quick rundown on the basics of the immune system and major supplemental players in this field.

One of the options is probably already in your kitchen if your taste buds have any self-respect.

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Why Do People Take Immune Booster Supplements?

When it comes to immune booster supplements, both research and the customer tend to focus around three major desires:

  1. I want to get sick less often (reduce sickness rate).
  2. If I am sick then I want it to go away faster (reduce sickness duration).
  3. If I am sick then I want it to be more bearable (reduce sickness severity).

Any compound that has reliable potency in even one of the above can rightfully call itself an immune booster. If something is able to beneficially affect all three categories? Well, to do that reliably would be a holy grail and make it a king among immunity boosters.

That holy grail doesn’t exist right now, to our knowledge, just a few knights rallying under the rightful queen that we’ll get into in a little bit.

Now, as for why people take immune boosters, it’s simply because getting sick sucks.

You feel bad, people don’t want to be around you, and your work productivity plummets. You can’t even enjoy yourself and sleep right when sick so, clearly, having some way to mitigate it would be nice.

How do we mitigate it? Well, beyond good hygiene, diet, and sleep, the supplemental ways to mitigate sickness are to improve how well your immune system is doing its job.

Let’s look into how we can do that.

How Do Immune Booster Supplements Work?

The strength of the immune system lies in your immune cells.

This is why most immune boosting supplements work by improving the function of your immune cells.

There are numerous different immune cells in the body that all work together to keep you healthy, which is why there are many ways supplements can go about improving immune health. Assisting any one of these immune cells can lead to benefits.

When it comes to dietary supplements usually the following four cells are implicated, although I can’t rule out the other cell types (you just don’t tend to see B cells or mast cells as targets of many supplements):

Macrophages can be seen as the “Pacman” cells of the immune system, since they literally gobble up infections.

If we are to use my favorite police force analogy here they are the basic cop unit. There are a lot of them, they do a lot of work, and if they can work well then the body is in good shape.

Supplements that improve their “phagocytic” activity (ability to kill their targets) include garlic and the herb Tinospora cordifolia, amongst others.

Natural killer cells (NKs) would be the SWAT cells of the immune system.

They also hold phagocytic capacity but tend to be more specialized, directed, and powerful. They are also the immune cell most implicated (at least with mushrooms) in seeking out and destroying cancer cells.

Supplements that improve NK cell activity include reishi (study) and spirulina (study) amongst others.

T cells can do some direct work but would be similar to office management in this analogy.

Their main purpose is sensing and directing the flow of other immune cells. They secrete messaging molecules (cytokines) and, in response to them, can alter their structure on the fly to change which new messages are sent out.

Alterations to how T cells work can influence the entire immune system to such a large degree the entire body can be put into either an inflammatory or an anti-inflammatory state; this is referred to as the TH1/TH2 balance and the inflammatory TH1 side is highly protective of the body and enhances immunity.

Dendritic cells are present in high levels in the intestines and are usually the first immune cells to make contact with the stuff we put in our mouths.

In this analogy they would be a police training academy since they’re able to direct the creation of new immune cells. They interact heavily with T cells and usually things that affect one affect the other.

Both T cells and dendritic cells are influenced by, well, pretty much everything we put into our mouths, but especially mushrooms and any traditional medicine that is a root vegetable and claimed to benefit immunity (ashwagandha, astragalus, etc.) are the more relevant ones.

If a dietary supplement can beneficially influence one of these four cell types then it can be reasonably argued to be an immune booster supplement.

There is, however, a major catch here. The list of things that can be “argued” to be an immune booster is absolutely immense—almost every single plant out there! Naturally, we don’t want to rely on just an argument, we want proof.

And we can’t really rely on research animals here.

There are indeed animal models out there to demonstrate that supplements influence the immune system but let’s look at this practically. We humans walk around all day putting unknown stuff into our mouths, touching things that we don’t know where they’ve been, and interacting with people who we have no clue what they do in their spare time.

Research animals are in labs that are, for the most part, very clean and uncontaminated.

When it comes to proving a dietary supplement interacts with the immune system, animal research is sufficient. To outright prove that it is a practical immune booster, however, may require human data specifically since there are so many practical differences between how we and research animals can get infected and sick.

So which immune booster supplements have the best human evidence?

The 3 Best Immune Booster Supplements

best immune boosting supplements

The top three immune booster supplement I’ve chosen are based on the amount of evidence supporting them. In vitro and animal evidence matters here but, of course, they all have human evidence as well.

Best Immune Booster Supplement #1

Pelargonium Sidoides

If melatonin is the undisputed king of sleep supplements, then Pelargonium sidoides (pelargonium) is the undisputed queen of immune booster supplements.

Similar to melatonin, it isn’t because “Queen Pelly” here has vast and wide-ranging benefits. It’s actually rather quite specific, for the treatment of acute bronchitis or any throat ailment that’s characterized by dry, coarse, coughs and “rattles” for it’s symptoms.

But god damn look at all the evidence supporting Pelly. The quality of the studies, the sample sizes exceeding hundreds, the benefits across all age groups.

All studies show absolute consensus. When the active dose is hit all symptoms go down by at least 60%, sputum (gunk you cough up) and rhonchi (rattling chest noises) go down by as much as 95%, and time to recovery is improved. Fever is also reduced by around 80 to 90%, fatigue goes down, etc.

And while the vast majority of benefits are specific to acute bronchitis, it’s possible this extends to other illnesses involving the throat. There are benefits to the common cold as well but, admittedly, these benefits are simply respectable rather than amazing.

The method pelargonium works through is similar to how cranberry works for urinary tract infections. The bioactives (in this case, umckalin and others) simply form a coat and prevent the sickness from sticking. If it can’t stick, it can’t do its job, and you fight an infection without resorting to antibiotics.

Remember in the intro when I called bacteria illegal immigrants? Preventing them from sticking is as close as you can get to building a wall unless you just, like, stop eating and breathing; that’s generally a bad idea though.

Pelargonium sidoides is currently the best researched supplemental immune booster known. Specific to acute bronchitis and possibly other upper respiratory tract infections, it reduces symptoms by over 60% while improving recovery time.

The clinically effective dosage seen in studies is, specifically, a liquid extract of the roots that is 1:8-10 (concentrated between 8-fold and 10-fold) dosed at 4.5 mL three times a day. The brand name for this extract is EPs7630.

If unable to get this extract about 800 mg of the plant’s root can be used as long as it’s not a pure water extract (since the beneficial compounds are in the fat soluble portion).

Best Immune Booster Supplement #2


We now enter the territory where evidence is a lot less robust.

Echinacea is perhaps the oldest herbal immune booster and is quite well studied— more so than pelargonium even as echinacea has multiple meta-analyses on it! The only issue is that there isn’t consensus among the data.

Meta-analyses find, overall, reductions in the duration of sickness and frequency of the common cold while others find contradictory results in studies and Cochrane (consistently high quality meta-analyses) stated that while benefits could theoretically exist overall the evidence doesn’t support echinacea.

Now, it seems the “issue” here is that nobody even really knows why echinacea boosts the immune system. Lots of theories, lots of individual studies on it, and lots of alkylamides that we cannot wrap our heads around yet.

Wait, what?

We don’t need to get too far into the weeds on this, but the short story is that the alkylamides are the group of molecules that exert the benefits of echinacea. There are many different kinds and they’re all structurally similar. They can be metabolized into one another in the human body and inter-batch variation (one bottle compared to the next) is surprisingly high.

So if one of them works, but the others don’t, which one is it and how can you assure you get that specific one in your body? Right now we don’t have the answer.

Plus, there’s even some evidence to suggest the above is all irrelevant as bacterial lipoproteins (like the Braun proteins in spirulina) or lipopolysaccharides are what causes the benefits.

So does echinacea work? A very, very robust maybe!

Honestly, the fact that echinacea is among the best three should go some ways in demonstrating how human studies for supplements boosting the immune system are relatively rare despite everything under the sun claiming to be an immune booster supplement…

Anywho, is it worth supplementing? Perhaps not on it’s own.

When it’s slipped into a product that you were going to buy anyways? Maybe. It’s safe and flipping the coin in the hopes of some upside when there are no downsides is nice if it isn’t expensive.

There’s clearly something in echinacea that seems great for immunity, as evidenced by some of the large body of studies, but it seems quite unreliable. Echinacea has the potential to be a great immune booster supplement pending more evidence if we are able to discover why the differences in studies exist.

The clinically effective dosage seems to be between 900 to 1,500 mg a day of the dehydrated aerial (above ground) parts of the plant, so anything but the root, divided into three daily doses of 300 to 500 mg.

Ethanolic tinctures also exist where 2.5 mL is taken three times a day.

Best Immune Booster Supplement #3



immune boosting supplement garlic

Garlic is my favorite bioactive food edging out nigella sativa and spirulina because it tastes significantly better than those two. The widespread benefits of garlic extend to immunity.

In particular, garlic supplementation (or dietary inclusion) seem to proliferate both the activity of natural killer cells and a specific T cell known as a gamma delta T cell (γδ-T). The latter immune cell is an atypical T cell and doesn’t do normal T cell things, in fact it gets down and dirty in hunting down infections much like a natural killer cell would.

Guess the immune system’s desk jockey got sick of paperwork and got back on his feet.

Human studies on the topic find a reduction in the common cold (less duration and frequency) when they have an appreciable amount of garlic in the diet while supplementation has been twice linked to lessened severity of the cold and flu to boot.

It hits all three parameters that we’re interested in but, alas, the evidence is rather limited. Still, a few human studies suggesting promise is quite nice even though we need more.

Garlic seems to help the body fight off infections but, beyond that, it seems to make the user more able to do work while sick and not need to take as many days off.

Pending more human evidence, garlic may very well hit all three targets we’re looking for: reduced frequency, duration, and severity of sickness.

The clinically effective dosage is about 900 mg of garlic extract (usually aged garlic extract) taken a day. If using fresh garlic then 2 to 3 cloves a day, crushed and eaten as is or with meals, can suffice.

Honorable Mentions

There are some honorable mentions that don’t have as much human evidence as the aforementioned three but, honestly, it feels weird to write an article on immune booster supplements without mentioning them in good faith.

Ganoderma Lucidum (Reishi)

Reishi is an honorable mention because, while I wanted the best three to be the ones with the human evidence on them, reishi is a great example of a bioactive polysaccharide source.

Bioactive polysaccharides tend to be found in mushrooms (reishi, turkey tail, cordyceps), algae (spirulina, chlorella), and some other traditional medicines for immunity (Tinospora cordifolia, ashwagandha).

These polysaccharides are not usually digested for calories (so they are more like fibers than anything) but interact with the dendritic cells in the intestines, specifically places known as Peyer’s patches which have lots of these cells, and thereafter influence the other immune cells.

While all bioactive polysaccharide sources differ in their effects they tend to be similar in other ways. They all improve the immune system’s ability to sense and fight off infections while also being anti-inflammatory. It’s a weird combo, usually those two things are dichotomous.

And reishi is my favorite source of bioactive polysaccharides.

In instances of cancer it’s been found to increase natural killer cell activity by up to 50% (although elsewhere it fails to hit statistical significance despite achieving a 35% increase).

Beyond that it seems to prevent cancer cells from protecting themselves against natural killer cells, enhancing their killing capacity. This may be why we have at least one human study showing a suppression of colorectal tumor size with reishi (quite rare for supplements to have this kind of data.)

Furthermore it simply makes more dendritic cells and macrophages, while improving the performance of the latter, and can influence T cells to become mature Treg cells (a different kind of T cell) that have anti-inflammatory properties. This is due to a unique protein in reishi.

The effects on natural killer cells and T cells are thought to be the reason why reishi has shown immunostimulant effects in athletes.

But alas, it’s an honorable mention because that appears to be the only human study on immunity in otherwise healthy subjects. Most reishi data is on colorectal cancer and benign prostatic hyperplasia (BPH).

Ganoderma lucidum (reishi) is a really cool mushroom and could very well be an immune boosting supplement but, according to my own words, I cannot say that it’s “proven” since the data in humans just isn’t that robust yet.

The clinically effective dosage of reishi is usually around 3 grams of a water extract taken daily (as the water extract contains the polysaccharides). Some studies use up to 6 grams of this extract a day and while it does not need to be taken many studies do so anyways.

Spirulina and Tinospora Cordifolia

immune boosting supplement spirulina

Spirulina and Tinospora cordifolia don’t have human evidence to suggest an overall reduction in rates/duration/severity of sickness, which is why they’re honorable mentions.

They both have good in vitro and animal evidence to suggest a possible benefit and they both have great human evidence, though.

For allergic rhinitis, specifically, and if your nose gets clogged when you’re sick—pay attention.

Nasal symptoms of allergies are outright abolished at rates between 61 to 83% with Tinospora cordifolia. Daily spirulina usage (low dose of 1 to 2 grams) in my fellow snot-kin who frequently get stuffy noses was more than twice as satisfactory as placebo (on a 1 to 10 rating scale, spirulina got 7.5 on average).

This is a topic close to my heart since my nose will once again attempt to kill me if I ever stop using Genesis (honestly, I know I am supposed to say I made this for the customers but in getting spirulina, reishi, and astragalus all in the same scoop I sorta made it for me too.)

Spirulina and Tinospora cordifolia are two supplements that you should keep an eye out for if your nose hates you and tries to drown you in snot at the first sign of sickness.

Spirulina is dosed at 1 to 2 grams a day for this purpose, taken at any time.

Studies on Tinospora cordifolia use 300 mg of a supplement that contains 5% “bitters” (what the bioactive ingredients are called) taken thrice daily with meals for a total daily dose of 900 mg.

The 3 Worst Immune Boosting Supplements

In line with previous articles that I’ve done on this topic where I rambled entirely too much on the good stuff, let’s rapid fire the horrible options.

Worst Immune Boosting Supplement #1

Vitamin C

Vitamin C is notorious for being the “failed” immune booster that’s still sold.

It first rose to fame with Linus Pauling who enjoyed vitamin C entirely too much, supported by some evidence that high dose vitamin C can help high intensity athletes not get sick as much. Then the entire field of researchers went crazy bull-headed in the direction of “vitamin C is a panacea and we’re gonna force new data on this topic every other week.”

It’s in the worst category despite the fact that it could work for high intensity athletes and how it can provide a wee benefit if you have marginal vitamin C status (eat some damn fruit if that’s the case) because it is overhyped to the high heavens.

Vitamin C is not a panacea. It’s just an extra little goodie that you might want to put in your face when sick or a reason to have some juice when you’re feeling ill.

Worst Immune Boosting Supplement #2


Lysine is, well, useless for the purposes we’re talking about.

Sickness rates, length, and intensity are not only not studied with lysine but there’s no major reason that lysine would even interact with the immune system of somebody who is adequately nourished.

The only real use lysine has is in the treatment of viral infections. It doesn’t really cure them, but herpes simplex sores (cold sores) like arginine and hate lysine; they’ll shrink and appear less visible if exposed to more lysine than arginine.

It seems that at some point the marketing got confused and “reduce cold sores” became “reduce colds” and the anti-herpes effects became anti-viral in general. Commonly sold with vitamin C, the combination with lysine is the epitome of cheap and ineffective.

Lysine has no evidence, nor major reason, to reduce sickness rates in otherwise well-nourished adults. It’s sole benefit is in reducing the size and visibility of cold sores.

Worst Immune Boosting Supplement #3

“Insert Fancy Fruit Here”

immune boosting supplement fruit

Surprisingly, the hardest part of this article was deciding which supplement would get the honor of getting the final smackdown. The first two are the most common but, after that, the floodgates just open up and everything comes pouring forth.

Now, to be clear, I’m not going to say that all fruits will fail here. Cranberries have similar properties as pelargonium after all (just working in a different area of the body) while elderberry has at least once shown benefit (related to antimicrobial properties).

But all too common the term “immune support” is tossed around alongside “antioxidant,” resulting in everything being thought to be an immune booster. Given how each year there’s a new exotic fruit claimed to be a cure-all, like acai or camu camu, every year this confusion will arise once more.

So just be aware that, given how infrequent data on supplements boosting the immune system is, the newer and exotic stuff rarely has evidence. If it does, like when I introduced you to Queen Pelly earlier, then you need to see the research immediately.

As a general rule of thumb, new and exciting supplements that are simultaneously called immune boosting and antioxidants are probably just marketing rather than evidence.

The Bottom Line on Immune Booster Supplements

Nobody truly needs an immune booster supplement but, when you get sick or are surrounded by sick people, it’s great to just buy and have in a cool, dark place for when you need it.

There’s no one-size-fits-all supplement for all sicknesses but we can narrow down what we want based on the type of sickness or what you want out of it:

  • If you frequently get dry coughs or throat ailments, especially acute bronchitis, have Pelargonium sidoides on standby.
  • Have garlic in your diet or supplement regimen at some point; consider food and supplements interchangeable as long as it’s a decent dose.
  • Have some nice bioactive plants in your diet. Again, either through a nice and varied diet or from taking some form of greens supplement with proven ingredients.
  • Keep spirulina and Tinospora cordifolia on standby if your nose hates you, or just take 1 to 2 grams of spirulina daily and forget about it.

Immunity was the primary focus when creating Genesis, our greens supplement, after all, despite it having other benefits to organ health.

So if you want to support your immune system, consider Genesis, which contains clinically effective doses of spirulina, reishi mushroom, astragalus, and 6 other ingredients for improving health, vitality, and immunity.  Also, consider adding some garlic in your diet if you’re not already taking Triumph (which contains garlic).

At least until our new product drops soon … long live Queen Pelly.

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What’s your take on the best immunity boosting supplements? Have anything else to share? Let me know in the comments below!