Marijuana and the Immune System: A Complex Relationship

Marijuana and Immune System

Whether it’s the common cold or stomach flu, coping with infections can leave you hanging by a thread. Immunity crashes can sometimes last for days and can leave lasting consequences as a result. However, there are those that would argue that when smoking marijuana, immune system functions simply flourish.

Here, we’ll discuss that argument in more detail by reviewing all the available literature on the relationship between cannabis and the immune system.

We’ll also approach the subject by posing questions, such as: how does weed affect your body, and how to increase white blood cells by smoking pot.

Overall, we’ve gathered valuable information about the immune system and dove deep into the scientific evidence about the immunity-effective traits of cannabis. Somewhere in the depths, we’ve found both compelling and contradictory arguments.

Jump right in, and find out what the key takeaways are.

Immune System: A Cannabis-Prone Landscape

Does weed weaken your immune system? Unfortunately, the answer is never as simple as the question itself. To find the answer to the question “how smoking pot leads to increased white blood cell count?” we need to do a quick “immunity” recap.

The immune system is a multi-organ structure with but one purpose: to fight off threats. These threats can be external (viruses, bacteria, fungi, toxins) or internal (tumor cells, dead cells, metabolic byproducts).

It fulfills this purpose by producing a spread of defensive mediators that circulate throughout the body. Defensive cells are also called leukocytes, or white blood cells.

Marijuana and immune system have a special connection, as immune system cells tend to react differently, depending on their type.

Furthermore, the immune system has two main forms:

Innate Immune System

This is your body’s natural defensive barrier, represented by the most prevalent white blood cells, such as macrophages, mast cells, dendritic cells, eosinophils, neutrophils, basophils, and natural killer cells.

Their response is non-specific. Meaning, they act on threats by default and do not leave lasting immunity.

It’s also worth noting that the most prominent marijuana effect on immune system cells is expressed through innate immunity.

The innate immune system is also referred to as “the inner maintenance system” as it purges the body of dead cells and inactive cell fragments. Its cells are produced in the bone marrow in the form of undifferentiated cell-entities that differentiate in the spleen and other designated tissues.

Adaptive Immune System

This defensive system is more refined as it attacks specific cells and leaves lasting immunity.

It is mediated through the lymphatic system, largely inhabited by two main cell-types, and cannabis immune system interaction is facilitated by them. These are:

  • T-Lymphocytes — they are responsible for cellular immunity and aid innate immunity cells in attacking more specific, structurally refined threats, such as viruses.
  • B-Lymphocytes — they produce antibodies that recognize and attack larger targets and carry out so-called humoral immunity. They are the dominant line of defense against pathogen bacteria.

Lymphocytes are produced in the bone marrow, mature in the thymus and lymph nodes, and are dispersed throughout the body via the lymphatic system.

Traits of Marijuana and Immune System

A lot of controversial arguments have been thrown around regarding the effects of cannabis on general health. However, most of them are not rooted in scientific facts.

Now, while smoking weed while sick may result in quick relief, in most cases, this will be predominantly due to its psychoactive effects. In other words, feeling relaxed and joyful certainly aids any ailment, but it doesn’t cure the underlying condition. It’s a lot more complex than that.

Therefore, before jumping to any conclusions, we explain the way in which cannabis interacts with the immune system.

Cannabinoids and the Immune System: an Overview

More than 100 different cannabinoids are found in the cannabis plant, yet not all of them have pharmacological effects. The ones that attract both scientific and consumer attention are, beyond doubt, cannabidiol (CBD) and delta-9-tetrahydro-cannabinol (THC).

The effects of cannabinoids in humans are studied both with in-vitro cell preparations and through in-vivo applications. Some studies even assess the effects of smoking weed made from standardized strains, whereas others focus on the impacts of injected marijuana extracts.

So far, it has been determined that the connection between weed and the immune system is facilitated via endocannabinoid receptors that modulate various physiological responses. In fact, both THC and CBD affect two kinds of these receptors, CB1 and CB2, which are abundantly displaced throughout the body.

CB1 receptors are predominantly found in the brain, spine, glands (thyroid, pituitary, adrenal, and reproductive), eyes (dominantly CB1), liver, and lungs.

CB2 receptors are more prevalent in the gut, bones, lungs, skeletal muscles, and throughout the peripheral nervous system.

On the other hand, both receptors ameliorate immune function. However, the answer to the question: “does weed lower your immune system?” lies much deeper in the specific expression by particular cells or tissues.

In general, CB2 is more prevalent in the immune system, but CB1 still seems to modify immune actions on some levels.

CB2 is abundantly found in the immune tissues of the spleen, tonsils, and in the thymus gland. Furthermore, these receptors show signs of activity in T-lymphocytes, B-lymphocytes, monocytes, and macrophages. They seem to modulate the immune response by modifying cell communication in tissues, facilitating bone marrow function in the immune system, and also affecting in-cellular metabolic activity in the cells.

The studies confirm that, when on marijuana, immune system cells tend to mature, communicate and act differently.

CB1 affects the immune system primarily via nerve stimulation of the tissues and cells, as the part of their neuroprotective function. What’s more, CB1 receptors are also found in T-cells, innate immunity cells, and to a lesser extent in B-cells.

The evidence repeatedly shows that the effects of cannabinoids on the immune system are predominantly achieved through CB2-mediated functions of cell maturation, and CB2-related immune cell activation. Additionally, CB1 seems to play a more silent, modifying role in the cellular immune response.

Now, let’s see how cannabis affects the immune functions by acting on these receptors.

Good and Bad Marijuana Effects on Immune System

Both CBD oil and medical marijuana effects are utilized for health-promoting purposes. Among others, they have been proven to have anti-inflammatory, antioxidant, antimicrobial, anti-nausea, and anticancer activities.

Don’t Activate, but Modulate

Regarding the effects on the immune system, it has been postulated that cannabinoids have immunomodulatory effects on the body. Meaning, they interfere with the chemical communication between both immune tissue cells and various immune cells within the systemic circulation.

A word of caution, immunomodulatory is not to be confused with immune-suppressing, or even with immuno-enhancing properties. This means that, when smoking weed, immune system effects are not just enhanced or debilitated, they are modulated to some extent.

We aim to clarify this: substances that express immuno-enhancing properties tend to stimulate the production of immune cells, such as with vaccines.

On the other hand, immunosuppressants lower immune system cell production or deactivate active immune. Immunosuppressants are generally used to disable graft rejection in transplants or to suppress overactive immunity in autoimmune diseases.

Immunomodulation is a regulatory adjustment of the immune response, which happens on an everyday basis. Endocannabinoids tend to regulate homeostasis both by amplifying or by attenuating the immune activity, according to the situation.

So, does smoking weed lower your immune system? Not exactly. It can both enhance it and suppress it. The cumulative effect depends on:

  • the product (smoking, vaping, or oil),
  • choice of a weed strain (THC/CBD ratio), and
  • the overall state of the immune system (healthy or overactive).

CBD vs. THC Effects on the Immune System

THC binds to both CB1 and CB2 receptors directly. However, according to the research, it affects CB1 with a higher affinity, compared to the lesser affinity shown towards CB2.

On the other hand, CBD acts on these receptors indirectly by modifying their response. In general, the effects of CBD on the immune system are more potent than that of THC, because it tends to act more intensively on CB2 and less on CB1 receptors.

Furthermore, high-THC cannabis strains tend to stimulate CB1 receptors, while CBD-only products tend to react via CB2. When taken together in the form of weed smoke, CBD acts as a modifying agent, as it behaves differently depending on the levels of THC in blood.

Immunomodulatory Effects of Cannabis

Marijuana affects the immune response in two ways:

  • It reduces inflammation in various tissues. The use of cannabis for inflammation is considered beneficial in cases of inflammatory and rheumatic diseases.
  • It directly affects active immune cells.

Conflicting Marijuana Effects on Immune Cells 

We strive to further the connection between cannabis and the immune system by determining which process is affected and in which conditions.

In healthy people, cannabinoids inhibit the activation of T-lymphocytes, thus lowering the cellular immune response. This is perceived as an impairment to fight viruses.

However, in immunocompromised people, such as in HIV-positive patients, therapeutic doses of medical marijuana have shown immuno-enhancing properties.

In the case of T-lymphocytes, THC is determined as the more potent suppressive agent, whereas CBD attenuates its inhibiting effects to some level. In fact, THC reduces up to 33% of overall lymphocyte activity.

Therefore, high THC-content products, such as THC-high medical marijuana and cannabis edibles, tend to decrease the overall immune action.

Furthermore, in B-lymphocytes, CBD is an immunosuppressant, and it acts by changing the cell metabolism and lowering the antibody production.

In addition, CBD lowers the immune response of innate immune cells, thereby debilitating the first line of defense against the external threats. The effects are predominantly perceived in the lungs and spleen as an impaired antibacterial activity.

CBD additionally induces programmed cell death of innate immune cells, thus decreasing the amount of lingering threat-responsive cells.

CBD adversely affects the immune function in fighting threats, but it aids in regulating the immune response in general.

In other words, CBD oil could be helpful when taken on a regular basis, for immune system maintenance, but you should be carefull with the dosing in the case of diagnosed infection.

How does CBD help the immune system?

Not every immune response is considered beneficial. In fact, local inflammation induces the immune cells to act, and this process is considered healthy when it serves the purpose of fighting against threats.

However, if over induced or inherently impaired, the immune cells start attacking healthy tissue, thus creating a chain reaction of damaging events.

CBD controls the ineffective or overactive immune response, making it more effective and less harmful. Therefore, CBD is effective in regulating immune response with autoimmune diseases.

For example, a high-intensity workout tends to induce heavy inflammation in the muscles. By lowering post-workout inflammation, CBD aids the immune system by inducing a lighter response, thus redirecting it to fight original threats.

The effects of CBD oil on the immune system are also perceived through its ability to aid in neuroinflammatory diseases, such as Alzheimer’s disease, or multiple sclerosis.

Cannabis and Immunity in Pregnancy

No human studies have been undertaken in this area. Nevertheless, there is evidence that suggests that the use of marijuana during pregnancy could impair the immune system of the developing fetus, thus lowering the innate defenses of the offspring.

The Use of Marijuana Products with Infections

Given that it negatively relates to the adaptive immune response, the use of marijuana-based products could potentially harm the body’s potential to fight pathogens, such as viruses and bacteria.

The Bottom Line

Feeling a bit under the weather? Try avoiding cannabis for a while. Why? Well, THC inhibits immune cell function by a huge margin. CBD, however, appears to affect the immune functions differently, and when used in lower doses, can even help the immune system overcome some challenges.

There are many aspects in which cannabis interacts with the immune cells, and all of them are dose-related. Therefore, responsible dosing is of utmost importance. Marijuana and immune system have a special, complex relationship.

The truth is that when you are using marijuana, the immune system functions are continually being modulated, and there is no sure way of calculating whether an external threat will beat the natural defenses.


Does smoking weed lower the immune system?

Smoking marijuana is generally perceived as unhealthy due to the combustion process. What’s more, it can additionally contribute to lung damage and the lowering of lung immune responses.

According to recent research, marijuana smoke damages lung tissue the same as cigarettes. In frequent users, it can impose substantial damage to the lungs.

Furthermore, when under a respiratory infection, smoking can lead to quicker onset of pneumonia.

Sharing joints is also risky, especially in the event of an epidemic, for the infective droplets are almost completely absorbed through the oral mucosa.

Do edibles weaken your immune system?

The relationship between marijuana and immune system remains the same, even when not smoked. Some edibles facilitate the deterioration of the immune system, by delivering cannabinoids right to it, through the lymph. Then again, it definitely matters how you make the edibles, i.e. how powerful ingredients you are going to use.

According to research, consuming bhang significantly decreases the absolute number of immune cells throughout the body.

8 thoughts on “Marijuana and the Immune System: A Complex Relationship

  1. Good article. There just enough good information out there about marijuana. Everyone has their opinion and those opinions are getting in the way of good science.

  2. I have elevated white blood cells. Is smoking marijuana every day the contributory factor?
    If I stop smoking every day will my white blood cell count decrease?

    1. Dear Lynn,
      Consuming cannabis every day is certainly a contributory factor to the rising WBC count.
      If a cannabis product is the only thing you’re using right now, lowering the dosage will stop this blood count’s rising trend, and could eventually lead to a decline.
      However, to be sure, we would need to consider other things, such as existing medical conditions and medications used.
      For now, it is safe to lower your cannabis dosage and track your blood results accordingly. The aforementioned decline is not likely to happen quickly.
      Take care!

  3. Not every immune response is considered beneficial. In fact, local inflammation induces the immune cells to act, and this process is considered healthy when it serves the purpose of fighting against threats. like I’m totally immune.

  4. I have a low white blood cell count (specifically neutrophils), otherwise totally healthy. Would smoking marijuana daily keep these numbers low?

    1. According to an 11 year-long study published in 2019, smoking cannabis mildly increases your white blood cell count, including neutrophils. So I would say that these two are unrelated.

  5. I have chronic leukemia i month diagnose started medical marijuna 3 weeks ago… cancer clinic want to give a radioactive pill….I refuse…Am I right?

    1. Dear Hilda, thank you for your comment. I hope that medical marijuana has helped alleviate some of the symptoms. I cannot comment on your decision regarding the radioactive pill. But I do advise you to discuss all the benefits and side effects of it with your doctor at length since they are best acquainted with your medical history. I assume your doctor is also aware of the fact you’ve been using marijuana for medical purposes? We wish you all the best with your treatments.

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