Captain, the immune system is boosted, and I donno what to do.
Mr. Scott. Starship Enterprise.

I think he said boosted. Might be one of those bacon/beer can examples.

It is flu and cold season and there are no end of suggestions that one should boost their immune system. Two million hits on the googles for the phrase ‘Boost Immune System’. Everyone from the Cleveland Clinic to the NYT to your neighborhood naturopath has suggestions. The options for boosting rival the number the stars in sky. Which in not that many, but still a fair number. Foods. Supplements. Minerals. Sleep. Exercise. Stress. And more.

But what does ‘boost’ actually mean? I have discussed this issue at least once upon a time but few people have the wisdom, or foolishness, to go back through the impenetrable file system that is SBM to discover my older writings. Their loss. Although I will note that my SBM writings are collected in Flies in the Ointment, available on Amazon and at your favorite independent bookseller. What is the point of having a blog if you can’t pimp yourself?

First, a caveat.

For those stumbling upon my writings for the first time, I am not an immunologist. I was an infectious disease doctor for 36 years, and most of my experience with the immune system concerned the consequences of when there was too little immune system (AIDS, chemotherapy, steroid use, etc.) or too much (autoimmune disease, cytokine storms with sepsis, etc.). My understanding of immunity is practical. I more like a mechanic, who understands how cars function and how to repair them, but has only a basic understanding of the metallurgy that goes into their construction or what it takes to produce gasoline. It is a metaphor I hope to beat to death.

How does one boost the immune system? It seems the concept is to make the system stronger than it’s baseline. To pump it up as if the immune system were a muscle. Maybe an Elvis reference would be better:

Down in the pleasure center, hell-bent or heaven sent
Listen to the propaganda, listen to the latest slander
There’s nothing underhand that she wouldn’t understand

Pump it up until you can feel it
Pump it up when you don’t really need it

Such a great album. And I don’t hear the theft. But I digress. As usual.

Make the immune system bigger, stronger, faster, more responsive? That sounds great. There are all sorts of supplements that say they can do that to at least one part of the body. Am I oversharing? Anyway, I would love to be able to improve many parts of me. But is it possible? Muscles can, with work and time, get larger and stronger. Most other parts? Maybe not so much.

First, what is the immune system? It is a kludge of physiologic processes that mostly keep us from being consumed by the tremendous number of microorganisms in the world. I once counted around 1,200 organisms – viri, bacteria, fungi, and parasites – that I needed to know for my job. Others have counted a few more:

∼1,400 known species of human pathogens (including viruses, bacteria, fungi, protozoa and helminths)

But that number rounds to zero when you include all the microorganism species in the planet. Depending on who is counting, there are around 2 million to a trillion bacterial species. Quite the range. And maybe 107 to about 109 viri, of which perhaps 320,000 can infect mammals, upwards of 6 million fungi and a paltry 75,000 and 300,000 helminths. I do not think that includes the helminth under the city of Sunnydale.

All of these microorganisms are kept at bay in part by the immune system. Many, such as viri, haven’t evolved to infect humans. Yet. And using humans as a reproductive strategy is apparently not a very good one, given the relative scarcity of human pathogens. Most of that is due to our core body temperature, as it is the rare organisim that can grow at 98.4, much less 101 or 102. That would be Fahrenheit. Even fewer can grow at 102 Centigrade, The Girl with All the Gifts or the Last of Us notwithstanding.

What is this immune system? It depends on whether you are a lumper or a splitter and if you want to include specific or nonspecific functions. I trend towards the splitter and nonspecific end of the spectrum.

Lets see if I can list them all. I have no doubt I will forget something.

There is the complement system with 33 proteins and three pathways by which it can be activated, depending on the pathogen.

There are antibodies, 5 classes and 9 subclasses, with differing sites of action and specificity.

There are white cells: PMNs, lymphocytes (three kinds of T cells, two kinds of B cells) and, with my favorite name, natural killer cells, (brought to you by Oliver Stone), monocytes, basophils and eosinophils, each with their own function.

The Toll-like system, of which there are 15 proteins. I like how it was named:

It was named after Christiane Nüsslein-Volhard’s 1985 exclamation, “Das ist ja toll!” (“That’s amazing!”), in reference to the underdeveloped ventral portion of a fruit fly larva.

That suggests either she is very easily amused or that of the Wikipedia is failing to provide a key piece of information as to just why the underdeveloped ventral portion of a fruit fly larva was so amazing. The hint is

It (the Toll system) was known for its developmental function in embryogenesis by establishing the dorsal-ventral axis.

There are a variety of non-specific proteins such as mannose-binding lectin and its activation pathway that help capture and kill microorganisms.

The dozens and dozens of regulatory proteins: cytokines and chemokines.

And the non-specific barriers to infection: being warmer than room temperature, intact skin, the microbiome, and being nutritionally replete in protein and vitamins.

Quite the hodgepodge of redundant and interlocking systems to keep the microbial world, and the occasional cancer, at bay.

Some parts of the system are better at combating viri, others for encapsulated bacteria, others for parasites. None of immune system seems worth a damn for some infections: Ebola, MRSA or C. septicum come to mind as examples.

It is unlikely that your immune system functions the same as mine. Small changes in the amino acids, polymorphisms, make you different than me, and sometimes with a better response to a specific infection, and sometimes a worse response. Whether you live or die from a given pathogen may depend on a single amino acid. My personal favorite is snot: have the wrong kind, you can die of meningococcus.

Considering the above list, what, exactly, are you boosting when you pay good money for an herb or a vitamin or some other nostrum that is allegedly boosting your immune system?

Nothing I can think of. The concept, metaphorically, doesn’t work. I prefer to think of the immune system more like an automobile. I told you I would beat this metaphor. A large number of interconnecting moving parts propelling your consciousness through a sewer of microorganisms. Especially true if you live in fill in your own location here. You are not going to make complement more, well, complementary. Or antibodies behave more antibodily. Or make white cells more able to eat and kill their victims.

The problem is that the immune system under these circumstances is a nebulous, not a concrete, concept that can’t be quantified in an individual to determine risk for infection. Sure, poor sleep, lousy diet, no exercise all lead to a general increase in risk for infection. But not everyone every time. I remember in med school we had to total up the number of stressors in our life and give them points. I should have been dead given my score. I was doing just fine.

The average immune system is more like a car that needs tuning back to factory conditions. It needs to be optimized, within reason. Unfortunately, for most folks the car they most resemble is a 1971 Ford Pinto. Kind of limited with what can be done for that heap, given the desultory way most are maintained. Can’t make a silk purse out of a sow’s ear by eating blueberries or taking echinacea or whatever diet or supplement is suggested.

If there is an intervention that leads to an immune system that functions better than its evolved optimum and has clinically observable effects, I can’t find it. It is all sound and fury, signifying nothing.

As best I can tell, the only way to boost the immune system would be to give a vaccine, you know, a booster. Hence the name: a booster will boost your antibody levels. Being re-exposed to a microorganism will do the same thing, but hardly seems worth it. And, as I think about it, the odd pleomorphic effects of the BCG vaccine. Outside of that, optimizing, not boosting, the immune system requires everything you learned in second grade to stay healthy: good diet, rest, exercise, avoid tobacco and excessive alcohol. All the things no one seems to be able to do, hence, I suppose, the hope for a simple solution to a complex behavioral problem.

Lets say you are not in the mood for the simple things to keep the immune system optimized. A proper diet (whatever the hell that might be, since everything you eat causes cancer)? A good nights sleep? Regular exercise? Gimme a break. I’m busy. It’s too hard. I rather go with an alternative intervention.

And all the SCAMs suggest that, yes, they can boost your immune system. There are so many websites, I will just touch on a few representative examples.

Chiropractic? You bet. 1.7 million hits on the Googles. And it is way impressive:

The chiropractic patients were found to have a 200% greater immune competence than those people who had not received chiropractic care, and they had 400% greater immune competence than those people with cancer and other serious diseases. The immune system superiority of those under chiropractic care did not appear to diminish with age.

Although if these results are published in the peer reviewed literature, it isn’t on the PubMeds. Others note concerning the immune boosting effects of chiropractic

Neil confirmed that spinal adjustments are associated with a central anti-inflammatory response.

I hate to be picky, but anti-inflammatory effects are, to my understanding, part of suppressing, not boosting, immune function. But I would not expect logical thinking from chiropractors.

During COVID – well, it’s still during COVID- the claims that chiropractic spinal manipulation could help the immune system were evaluated and found wanting:

ICA (International Chiropractors Association) provided no valid clinical scientific evidence that chiropractic care can impact the immune system.

I was shocked to read that.

And in Canada,

Chiropractors told to remove posts claiming their methods boost immune system and prevent COVID-19.

There’s no scientific evidence that chiropractic care can boost immune system

My search of the Pubmeds finds no compelling studies of chiropractic doing anything one way or the other to the immune system, a case where the absence of evidence really is evidence of absence, I suppose.

OK. Chiropractic seems to be a dead end for getting my immune system boosted. Acupuncture? That ancient modality? Yep. 2.8 million hits on the Googles on boosting the immune system.

Similarly, there are a large number of Pubmed hits as well, around 1,500, although these mostly concern the anti-inflammatory aka immune suppressing, effects of acupuncture. If there are clinical studies to show benefit of acupuncture in preventing infections, my google-fu is off. Most of the studies concern giving patients infections from acupuncture, so acupuncture is not so immune boosting under those circumstances.

The one review I found on the use of acupuncture for the prevention of infection, I suppose a surrogate for boosting the immune system, was the usual word-salad gibberish that marks most SCAMs:

According to the occurrence and development of infectious diseases, ancient Chinese doctors established the theory of ‘Wei, Qi, Ying, Xue System’ to treat infectious diseases dialectically, and divided the development process into various syndromes such as WeiFen, QiFen, and YingFen, and XueFen in order to reveal the evolvement of these diseases from the slight to severe stages.

However many a practitioner will credit acupuncture with boosting the immune system. As an example, my first Google result:

Even just one acupuncture visit will make you less susceptible to viruses and other pathogens. For starters, acupuncture strengthens a weakened immune system by increasing the production of red and white blood cells and T cells (1).

It does? So I went to the reference, where I could only access the abstract. Paid with our tax dollars I will note.

The anticipation of acupuncture, simple insertion of needles or the electrical stimulation of needles at both classical acupuncture points and “false” points, all produce an increase in white blood cell count. Electrostimulation produced the greatest, expectation of needle insertion the least, increase in white cell count. Though needles remain to place, the white cell count returns to basal level within one hour.

Not impressed. Pain and stress will transiently increase WBC, be it at real or false acupuncture points, which is what likely occurred here.

The further down the rat hole you go, the worse it gets. Two sites suggest immune boosting acupressure for cold and flu prevention. Each suggests different acupoints. Should I press here or here? But of course the pressure points are different. Why do I expect consistency in non-traditional Chinese pseudo-medicine?

How about homeopathy? Of course. Almost 5 million hits. Who knew water was so powerful? Homeopaths have a variety of nostrums that purport to enhance immune function, although like acupuncture there is more focus on the anti-inflammatory effects, of which there are none.

Looking through the Pubmeds, I can fine nothing to suggest an beneficial effect of homeopathy on immune function. Except, as I am sure you are aware

A previous mathematical model described the Vf as a quantized gyroscopic “wave function,” equating strength of symptom expression to degree of Vf gyroscopic “precession.” Diseases and homeopathic remedies were interpreted respectively as braking and accelerating “torques” on Vf “angular momentum.” In this paper, approximations applied to the Vf “wave function” could provide insights into why conventional medicine dismisses the action of highly potentized homeopathic remedies. In addition, a simple geometric force diagram provides another mathematical model for allopathic drug action and immune system reaction.

What kind of dressing do you use with that word salad?

Of course, naturopaths are all about immune boosting. 3.7 million hits. But, it is always natural boosting. As best I can tell, virtually anything and everything, from bone broth to sunshine, can be immune boosting. It is a miracle that anyone needs immune boosting given the ubiquity of boosting interventions. I suppose they work best in conjunction with the credit card transaction being approved.

But pick a SCAM. Any SCAM. Search the Googles with immune boosting. You will get a hit. So what is a poor person do with so many options? Nothing really. Save your time and money and stick with the classics.

But really. You do not want your immune system boosted. In the biz we call that an inflammatory response and, while good for killing of infections, it is not without risk.

Every process has its downsides, including the inflammatory response. Newtons second law of physiology: for every beneficial action there is an equal an opposite adverse reaction. Acute and chronic inflammation are associated with a variety of bad outcomes from clot to dementia. I would suggest that the immune system has evolved to be more or less in the needed sweet spot and should be left to its own devices.

So is there a natural experiment where the immune system is chronically up-regulated?


It has been postulated that obesity is a left over complication of an evolved response to tuberculosis in pregnancy. The two states do have some physiologic similarities and obesity, like pregnancy, is protective against tuberculosis and perhaps other infections. It is a messy literature. And we are all aware of the physiologic downsides of obesity. Boosting the immune system, up-regulating it, could potentially have the same dire effects. But at least you would not get consumption.

I would suggest that the downsides of boosted immune system and obesity outweigh (I did not realize the pun when I first wrote this), at least in modern times, the risks of Tb.

So leave you immune system alone. It has evolved to be more or less optimized. If you want to correct your polymorphisms with a little CRISPR, be my guest. And if you could boost it? Which you can’t. Beware. No good deed goes unpunished.



  • Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at

Posted by Mark Crislip

Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at