The effect of marijuana on the brain has been a subject of interest for scientists and users alike for quite some time. Using available scientific data, we shall explore some of the misconceptions and debunk the myth that using marijuana kills brain cells.

For a long time, cannabis has been illegal in many jurisdictions around the world. In recent years, we have seen several states across the US legalize its use for medical and recreational purposes.

Canada has followed suit, and other countries consider measures to make this plant accessible to their populations.

The classification of marijuana as an illegal substance hindered the scientific community from conducting intensive studies on the plant. But recent findings have shed light on its physiological interaction with the human body.

Most of the benefits that have been identified have led to the legalization wave we have seen across the United States.

So far, studies have provided valuable insights into the effects of marijuana on the brain.

The Link Between Marijuana And Brain Cells

THC or delta9-tetrahydrocannabinol, the active ingredient in marijuana and other cannabinoids found in the cannabis plant, has positively impacted the endocannabinoid system (ECS) in the brain.

This link is important in understanding how cannabis does not kill but actually augments brain cells' growth.

CB1 receptors within the ECS in the brain respond effectively to cannabinoids. Activating cannabinoid CB1/CB2 receptors has been shown to affect brain cell growth, pain, anxiety, depression, and stress, which are all controlled by the brain.

Notwithstanding the persistent concerns related to the effects of marijuana, current research shows that the cannabinoids found in this plant can modulate the activity of cannabinoid receptors in the brain to activate neurogenesis – the growth of new brain cells.

Cannabichromene, or CBC, a cannabinoid native to cannabis, is a principal actor in stimulating brand new brain cells' growth.

This chemical enhances the generation of Neural Progenitor Stem Cells (NPSC), which, in turn, create astrocytes. Astrocytes are cells in the central nervous system that repair and replace the damaged areas of the brain.

The Brain, Depression, Stress, And Marijuana

Stress, anxiety, and depression are factors that directly impact the state of the brain. When left to reach unmanageable levels, these factors can damage the brain structure and exacerbate any chronic diseases present. Marijuana has, for centuries, been used to relieve stress and anxiety.

Cannabinoids found in marijuana act on the ECS to protect the brain from the effects of stress and anxiety.

Protecting the Brain

Rather than kill brain cells, marijuana is confounding critics by offering protection to the brain. Several areas of study have been of great interest to researchers looking at the effects of marijuana on brain cells.

Brain Tumors

Studies have indicated that THC, found in cannabis, can kill cancerous tumors in the brain. Research conducted on rats by scientists at Complutense University, Spain, cannabis extracts has been shown to block a key chemical needed for tumors to grow blood vessels.

The team observed that mice administered with THC recorded significant shrinkage in brain tumors' size by eliminating the cancerous cells.

The study affirmed that marijuana extracts inhibited the expression of several genes linked to vascular endothelial growth factor (VEGF) production, a chemical needed for tumors to sprout blood vessels.

VEGF is critical for tumor growth, and marijuana’s action to lower its activity in mice and human brain cancer patients led to a reduction in tumor size.

These findings strongly indicate marijuana’s potency in protecting brain cells.

Alzheimer's, Parkinson's, and Huntington's disease

Alzheimer's, Parkinson's, and Huntington's disease are known to cause brain inflammation in humans.

Studies have shown that cannabinoids found in marijuana effectively reduce such inflammation and restoring damaged brain cells.

The oxidative properties of these marijuana extracts are critical in expunging free radicals from damaged brain cells.

Cognitive Decline

The cognitive ability of humans declines with age. This is a natural process that can surprisingly be reversed by smoking weed.

Researchers at the University of Bonn, Germany, studied the mammalian endocannabinoid system and found it has molecules that balance the body’s response to stress.

The calming effect of THC, which is found in marijuana, is very similar in action to these molecules' behavior.

To take this further, the researchers gave aging mice a steady dose of THC but in small amounts that did not cause any psychoactive effects.

The results were simply astounding. After one month, the aging mice performed cognitive tasks such as finding their way around mazes with improved performance compared to those that did not consume THC.

Of particular interest was that THC boosted the number of connections between brain cells in the hippocampus, which is involved in memory formation. Since endocannabinoid activity declines with age, stimulation using THC restores it to optimum levels that are critical for cognitive ability.


Scientific studies have shown that the cannabinoids found in marijuana have beneficial effects on the brain. More findings have also indicated that THC use, in particular, protects alcoholics from alcohol-induced brain damage.

Studies are continuing to determine from what age this can be deemed optimally beneficial, but in a nutshell, smoking weed does not in any way kill brain cells. It reverses brain aging and restores learning and memory, and stimulates the growth of new brain cells.