Caffeine and THC are some of the most widely consumed psychoactive substances worldwide. Because of widespread use, there is an anticipated amount of overlap and possible interaction.

Many marijuana smokers wake and bake to start their day off right while also drinking a cup of coffee or their favorite energy drink. Increasingly, companies are unveiling infused coffee products with CBD or THC. There are a plethora of recipes online for cannabis coffee.



Caffeine and Cannabis

Caffeine is the favorite licit drug across the globe, with roughly 80% consuming caffeine daily. The allure of caffeine increases attention and arousal while also enhancing performance following sleep deprivation or distracting situations.

Sleep deprivation has never been this chronically widespread in human history, leading us to reach for caffeine to provide the necessary jolt to make it through the day.

Caffeine works by stimulating the brain and central nervous system after it’s absorbed by the bloodstream. In the brain, caffeine blocks adenosine from acting, which generally would induce tiredness.

Typically adenosine accumulates throughout the day, leading to fatigue and a desire for sleep by the end of the day. Caffeine also increases levels of dopamine, the feel-good neurotransmitter, and norepinephrine. 

It’s important not to underestimate caffeine’s ability to affect behavior and emotions as a psychoactive drug. Caffeine reaches the bloodstream in roughly 20 minutes and reaches full effectiveness about an hour after consumption. 


Marijuana is surpassed by caffeine and alcohol in use, most likely because of marijuana’s long history as an illicit drug. More and more states are moving to legalize recreational and medical marijuana use.

Cannabis has been highly regulated in all states since the 1930s and was completely outlawed in 1970 by the Controlled Substances Act (CSA). To this day, cannabis remains a Schedule I drug, which means it remains federally illegal for all purposes.

Colorado and Washington legalized recreational use in 2012, followed by Alaska, Oregon, and Washington D.C. in 2015. More states have followed suit in the last few years. 


Despite the efforts to minimize use by the federal government for decades, marijuana is beloved by many and roughly 22 million daily users. Cannabis has various strains that produce different effects, effects that can even vary for the individual.

Like caffeine, Sativa is a stimulant and, when combined with coffee, can increase the buzz, alertness, and productivity of the user. Indica acts like a sedative, producing a nice body high and can induce sleepiness. Indica may not pair as well with caffeine since they counteract each other. 

State of Research 

There has been some research into the possible interactions between caffeine and THC consumption, but it remains limited. Much of the research has been conducted using lab experiments instead of human trials. 

Endocannabinoid System 

Endocannabinoid Suppression

Research has demonstrated that the endocannabinoid system (ECS) may be suppressed by excessive caffeine consumption. The ECS is a body system responsible for regulating metabolism, memory, stress response, sleep, appetite, and immune response.

The ECS receptors, CB1 and CB2, are spread throughout the body to accept specific endogenous neurotransmitters. A study published by the Journal of Internal Medicine examines levels of metabolites following caffeine ingestion.

The researchers required all participants to eliminate coffee for one month to set a baseline. Then the participants drank 4 cups of coffee daily for four weeks which was then increased to 8 cups a day for another four weeks.


molecularCBD 1

During the weeks the participants were consuming higher caffeine concentrations, the metabolites associated with the ECS system were reduced. The ECS was being inhibited at these higher consumption levels and metabolizing less over time.

It seems that chronically high levels of caffeine can lower endocannabinoid levels in the body. Because endocannabinoids are inhibitors of nerve activity, the human body may have a more challenging time relaxing. 

Users may need to monitor their caffeine consumption and keep it at a moderate level to ensure the ECS can perform its important homeostatic functions. Users with chronic anxiety and stress should be especially aware that they may be handicapping themselves by consuming high caffeine levels. 

Limiting The High

A study using Squirrel Monkeys yielded interesting results when allowing the self-administration of THC under different caffeine levels. The monkeys were ingesting MSX-3, which is a compound similar to caffeine. Low doses of MSX-3 corresponded with lower THC self-administration.

However, when the monkeys were administered higher doses of MSX-3, they ingested more THC. This seems to support the 2018 article from the Journal of Internal Medicine. At lower caffeine levels, the ECS functions decently well.

The endocannabinoid system is slowed down at higher levels, and the high from ingesting THC may be muted. Ingesting more THC may be needed to reach a sufficiently high to reduce stress and relax.

For everyday users that already suffer from significant tolerance issues, reducing caffeine intake may help improve one’s high. The major takeaway from these two studies is that caffeine and cannabis are safe together, but caffeine consumption should be monitored to prevent interference with one’s high and with the body’s endocannabinoid system.

Neurotransmitters and Enzymes 


This next study, published in 2017, looked at vital neurotransmitters and enzymes in juvenile rats when administered caffeine and cannabis for 21 days. The study showed a statistically significant increase in the neurotransmitters GABA, dopamine, glutamate, and the enzymes G-6-PDH and Cytochrome C oxidase.

The study was broken into five groups. The control group, Group A, received no caffeine or cannabis. Group B received a high dose of caffeine, Group C received a low dose of caffeine, Group D received a high dose of cannabis, Group E received a low dose of cannabis, and Group F received both a low dose of cannabis and caffeine. 


GABA is a neurotransmitter that blocks nerve cell impulses in the brain. Higher levels of GABA can elevate mood and provide a relaxing effect, while low levels are associated with anxiety, mood disorders, and chronic pain.

GABA levels were significantly higher in all test groups compared to the control. This indicates both caffeine and cannabis can increase GABA levels and promote sleepiness while reducing anxiety, memory, and alertness.


Dopamine is commonly known as the ‘happy’ or ‘feel good hormone. This neurotransmitter is responsible for the feelings of happiness experienced by humans. Low levels of dopamine are associated with depression and related symptoms.

Major depressive disorder (MDD) is linked to a dysregulation of the dopamine system. The associated symptoms include lack of interest and motivation in enjoyable or favorite activities, difficulty concentrating, low alertness levels, and increased fatigue.

This study for dopamine again showed a significant increase in dopamine levels for all test groups compared to the control group. Caffeine and cannabis, either together or alone, contribute to higher dopamine levels which explain the euphoria and general happiness many regular users experiences. These happy feelings keep users returning again and again to their marijuana and morning coffee. 


Glutamate is an excitatory neurotransmitter, the most abundant in the human body. Glutamate is the precursor to GABA synthesis. This neurotransmitter is vital to cellular metabolism. In the brain, glutamate promotes learning and memory processes. Current research is investigating glutamate’s role in emotional learning.

It is believed that proper glutamate levels and function may be necessary in preventing the development of anxiety disorders, which are failures in dynamic systems. Once again, the glutamate levels were significantly elevated in all test groups. 

G-6-PDH Enzyme 

G-6-PDH is an enzyme crucial to the processing of carbohydrates and red blood cell protection. G-6-PDH is responsible for protecting red blood cells as they carry oxygen throughout the body from damage. If the gene associated with G-6-PDH, G6PD is damaged, this enzyme’s important function can be disrupted. This can lead to a catastrophic loss of red blood cells. 

In the study, the caffeine groups saw a higher increase in G-6-PDH than the cannabis groups. But Group F, the low dose caffeine and low dose cannabis group, saw a dramatic increase in G-6-PDH levels. It makes sense that caffeine which is associated with improved performance produces a greater change in the G-6-PDH enzyme that is involved in glucose processing. 

Cytochrome C oxidase

Cytochrome C oxidase is the enzyme responsible for the oxidation of food. Because both caffeine and cannabis act as stimulants, it logically follows that any metabolic function may increase with consumption. Cytochrome C oxidase levels increase in all control groups. 


Cannabis has been extensively studied in recent years to tease out beneficial and harmful effects on the body and brain. Research has shown that THC induces short-term memory deficits during peak concentrations.

Conversely, caffeine is known for its ability to clarify the mind and improve performance, whether it’s in school, work, or other life activities. Does combining caffeine with THC attenuate the short-term effects that THC has on memory? Research suggests no. 

A study published in 2012 examining rats’ working memory showed that caffeine was unable to counteract the memory deficits observed with THC uses. Various dosing combinations of caffeine and THC were administered to the rats.

The rats underwent a series of memory tests and were incentivized with food pellets. Unexpectedly, the rats performed better if they only consumed one of the psychoactive substances. Combining the two could lead to an increase in short-term memory deficits. 

Researchers believe this is primarily due to caffeine’s antagonistic effects on adenosine A1 receptors. When the A2a receptor was specifically targeted, memory was not detrimentally affected at low doses of THC. It seems that chronic caffeine exposure potentiates short-term memory deficits through this A1 receptor. 

Safe Consumption 

coffe and cannabis

Ultimately caffeine and cannabis consumption is safe. The research into the biological interactions caused by cannabis and caffeine is limited but certainly does not set off any alarm bells at this time. Much of the cannabis research has investigated potentially harmful effects because there is a severe lack of research on positive effects.

Hopefully, with the legalization tide turning, more investment will be made into the research of this kind. It’s quite unfortunate that such little research has been done on the interactions between two enjoyable and beloved psychoactive substances with massive numbers of daily users. 

 Moderate caffeine consumption seems most important. Refilling that coffee cup or reaching for that third or fourth energy drink should be minimized, especially if you want to promote a healthy uninhibited ECS system.

The benefits to your neurotransmitters and enzymes are significant even with low doses of caffeine and THC. A regular smoker is unlikely to be affected by any short-term memory issues and will be aware of their capabilities, but caffeine could attenuate these deficits. 

Edibles should be consumed with forethought. Edibles are metabolized much more slowly than inhaled marijuana. When smoking, the THC levels peak after roughly 15-20 minutes, whereas the liver has to metabolize edibles.

It can take 6 hours before an edible is fully metabolized and THC blood levels peak. This intense high is beloved by many, but mixing with caffeine that must also be metabolized by the liver, may produce more significant interactions. 

Finding Your Routine 

To be a responsible user of any psychoactive drug, it’s essential to understand your interaction with each drug. Only you know how you act, your tolerance levels, and your level of comfortability. You may need to experiment with dosing to determine the point where you function best.

Different coffees and other substances have different levels of caffeine. Waking and baking may not be desirable if you are smoking and consuming coffee at the same time. Vaping or edibles may be preferred, or even CBD-infused coffee. Find your sweet spot and enjoy the productive but relaxing start to your morning. 

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