When You Smoke Marijuana, This Is What Happens To Your Body

Marijuana, also known as cannabis, weed, pot, and a slew of other names, has been cultivated for millennia (via Science). The plant originally evolved on the eastern Tibetan Plateau, according to a review study of ancient pollen. It's since been used in recreational, medicinal, and spiritual contexts across myriad cultures, most commonly smoked in a pipe or hand-rolled cigarettes, known as a "joints," but also ingested in the form of "edibles" or brewed tea (via National Institute on Drug Abuse).

The decriminalization and legalization of marijuana in recent decades has led to greater social acceptance, enabling a more honest scientific discourse surrounding its effects (via The Washington Post). Unlike most other drugs, cannabis is classified as a depressant, stimulant, and hallucinogen, all in one (via Healthline). Each strain contains its own concentrations of the cannabinoids Tetrahydrocannabinol (THC) — its main psychoactive chemical compound (via Live Science) — and cannabidiol (CBD) — which lacks psychoactive effects but is lauded for its health-boosting properties (via Harvard Health Publishing).

Cannabis-induced symptoms seem predictable: The munchies, the sudden urge to philosophize, a classic wave of paranoia, or the feeling of life's stressors melting away (via Wired). But the effects of smoking marijuana can manifest in diverse ways depending on the person, strain, and environment. The same joint can make one person feel totally "zen" and another teeter on the edge of a panic attack. Here are some changes that occur in your body when you smoke marijuana, including positive and negative side effects.

Some people turn to weed as an anxiety queller (via Healthline). After a toke, cannabis users may feel relaxed, mellow, and lightheaded — consistent with the "chilled out" stoner stereotype. Based on a 2017 national survey, 81% of Americans associated marijuana with one or more health benefits — 47% of whom said they used it to provide "relief from anxiety, stress, and depression."

The psychoactive compound CBD has been largely credited for the calming effects of marijuana. A 2018 study showed that medical cannabis with high CBD and low THC levels resulted in a 58% reduction in anxiety, and a 2019 study of patients with anxiety and sleep problems found that CBD lowered their anxiety over a one-month period. There's evidence that THC can also reduce stress in low doses (via UIC Today).

Experts don't claim to have any definitive theories about how CBD works (via Healthline). But it's believed that the cannabinoid passes through your lungs into the bloodstream when you smoke, stimulating (rather than binding to) the endocannabinoid system's receptors and causing your body to naturally create its own stress-busting cannabinoids (via Medical News Today). In particular, marijuana enhances the effects of the neurotransmitter GABA, which is known to curb anxiety, suggests research.

At elevated concentrations, CBD activates the 5-HT1A (hydroxytryptamine) serotonin receptor, which underlies weed's antidepressant-like characteristics, according to a 2014 study. CBD may produce similar effects as serotonin, the body's "happy hormone," and a neurotransmitter that regulates mood, sleep, and other bodily functions (via The Scientific World Journal).

Smoking weed has long been hailed as a creative lubricant. Many artists have spoken openly about their use of the plant to get the creative juices flowing. The comedian George Carlin joked that he always kept a joint nearby to help open up "doors of perception" (via Artsy). Research suggests that cannabis can augment creativity by helping users feel less inhibited. Smoking weed is said to engender "psychotomimetic effects," which means that your perception of reality is shaken and your brain is better able to make novel connections and generate unique ideas, allowing you to step outside of your usual patterns of thinking.

Neuroimaging studies have shown that marijuana stimulates cerebral blood flow to the brain's frontal lobe, nucleus accumbens, and amygdala, namely regions of the brain that light up during divergent thinking — a scientific measure of creativity (via Mic). This type of thinking is spontaneous, non-linear, and solution-focused, typically occurring during activities like brainstorming, according to research published in Psychopharmacology. As with most therapeutic uses, the dosage is important, per Mic. The THC in cannabis can make non-creative people more creative when administered in small doses, whereas studies show that high-potency cannabis can actually hinder divergent thinking in regular users.

According to the findings of a 2017 study in the journal Consciousness and Cognition, people who use cannabis score higher on creativity as well as "openness to experience" on personality tests, which poses a causality dilemma: Does smoking pot help stimulate unconventional thinking, or are naturally creative people more inclined to get high?

Red, bloodshot eyes is one of the tell-tale signs of marijuana use. This was once believed to stem from irritation caused by cannabis smoke, but scientists now know this to be another side effect of vasodilation, notes McGill University's Office for Science and Society. When THC binds to cannabinoid receptors, it causes your blood vessels and capillaries to dilate, which, in turn, lowers your blood pressure and increases blood flow to the eyes, giving you that red, glassy-eyed look. It can also explain why some pot smokers feel dizzy.

"It's cannabis' ability to reduce intraocular pressure in the eyes that makes it a potentially viable treatment for glaucoma, a group of eye disorders that causes damage to the optic nerves which can eventually lead to blindness," Melanie Bone, a board-certified OB-GYN, told Weedmaps. Though, some studies have challenged the idea that marijuana can treat and relieve symptoms of glaucoma, with a 2018 study suggesting that CBD might even exacerbate the disease by raising eye pressure.

Furthermore, an allergy to cannabis or an adverse reaction to smoke isn't out of the question when it comes to the cause of your bloodshot eyes, warns Leafly.

One of the ways in which marijuana contributes to pain relief is through its anti-inflammatory properties, explains a 2018 study in Frontiers in Pharmacology. THC exerts its anti-inflammatory action by activating the CB1 receptor in the central nervous system, which plays a key role in perception (via ScienceDaily). But most importantly, THC activates the CB2 receptors on immune cells, which reduces the body's pain-inducing reaction to inflamed tissue.

Caryophyllene — a terpene found in cannabis — has also been found to activate CB2 receptors, bringing down inflammation and lessening your feelings of pain. The non-cannabinoid compound is said to be most abundant in certain indica and hybrid strains, and may help treat various chronic and inflammatory illnesses like colitis and Alzheimer's disease, per Leafly.

CBD also tames inflammation by decreasing the production of cytokines, which are chemical messengers in the body that help generate inflammation to fight off infections and viruses, explains a 2020 study in Nature. The authors conclude that CBD may be beneficial in treating chronic pain conditions like rheumatoid arthritis, especially when used in combination with antirheumatic medications, but further research is needed to carefully document CBD's anti-inflammatory effects.

Marijuana has been subject to scientific investigation for decades (via Scientific American). Yet, with over 400 ingredients, some of which have opposing effects, the biochemistry of this complex plant is yet to be fully understood, according to a report in Therapeutic Advances in Psychopharmacology.

Smoking weed doesn't typically yield hallucinogenic-like qualities, but some users have reported psychedelic effects, including hallucinations and trip-like experiences, which have mostly occurred after consumption of purified THC as opposed to the entire plant, according to a 2018 case report published in the journal Cannabis and Cannabinoid Research. The authors speculate that the hallucinatory effects of cannabinoids are rooted in the effects of exogenous cannabinoids on 5-HT or NMDA receptors. Smoking certain strains of the plant, in particular those that contain a higher concentration of THC, is known to produce psychedelic-like experiences (via WayofLeaf). But scientists are still trying to figure out how and why this happens.

A 2021 study published in the Journal of Psychopharmacology lends support to the idea that high doses of THC can induce similar states of altered consciousness as psychedelics like LSD or psilocybin. Specifically, some users have reported a sense of "oneness" with the universe, described by psychologists as "oceanic boundlessness," as well as "mystical experiences" that include feeling connected or "at one" with their environment, or a "revelatory sense of awe." Research shows that feelings of oceanic boundlessness can be therapeutic with positive outcomes for mental health, similar to the effects demonstrated in clinical trials of psilocybin and LSD.

Cotton mouth is a familiar side effect of smoking marijuana, which refers to the dry or parched feeling in your mouth, tongue, and throat (via Mic). This commonly accepted phenomenon, which goes by the scientific name xerostomia, stems from a lack of saliva. This occurs when THC binds to the endocannabinoid receptors in the submandibular glands in the mouth, blocking signals from the parasympathetic nervous system, and temporarily preventing the secretion of saliva, per Mic.

THC zips throughout your body and makes its way through your bloodstream before attaching to the cannabinoid receptors, Lewis Nelson, professor and chief of the division of medical toxicology at Rutgers New Jersey Medical School, told Mic. Therefore, how you consume the plant — whether by smoking or ingesting it as an "edible" — doesn't really make a difference when it comes to suffering from a case of cotton mouth.

While it may feel like the Saharan Desert inside your mouth, smoking weed doesn't necessarily dehydrate you. "It's just that the glands are shut down," explained Nelson. Needless to say, practicing proper hydration is always a good idea, just be sure not to overdo it, he warned.

While the effects of cannabis on libido have yet to be studied extensively, it's common to hear of people lighting up a joint to amp things up in the bedroom. A 2017 population-based study published in the Journal of Sexual Medicine reinforced the link between marijuana and sexual desire, revealing that cannabis users reported having more sex compared to those who abstained from weed.

According to a 2019 cross-sectional study, women also reported increases in sex drive and improved satisfaction with orgasm after smoking weed. The authors postulate that the plant interacts with cannabinoid receptors in the hypothalamic-pituitary-gonadal axis, which regulates sex hormones, including gonadotropin-releasing hormone and oxytocin release. THC also impacts testosterone levels. These interactions improve sexual function in various ways, such as by lowering sexual inhibitions, heightening and prolonging pleasurable sensations, and increasing confidence and the willingness to experiment.

Some men consider marijuana a "natural viagra," citing increased sexual stamina after smoking, according to research, but things may not be as they seem. Oftentimes, what they're really experiencing is a distorted perception of time, which leads them to think that they're lasting a lot longer than they are (via Mic). However, Mitch Earleywine, a professor of psychology at the University at Albany, SUNY, told Self, "Animal research suggests that stimulating the CB1 receptor delays ejaculation, so reports about the time of the act in humans could be true (and not just a result of impaired time perception)."

The forgetful stoner trope has endured pop culture for decades. And while the occasional drag from a joint is unlikely to cause cognitive damage, there appears to be some evidence that regular cannabis consumption can negatively affect your memory. Smoking cannabis may be even more damaging to the developing brains of teenagers than alcohol, reports a 2019 study, suggesting that the plant alters the brain's neural tissue.

In particular, marijuana has been found to compromise thinking, short-term memory (where recent events are stored), executive function, and psychomotor function, namely movement that requires attention and coordination like driving a car (via Harvard Health Publishing). THC binds with receptors in parts of the brain that play a key role in memory formation, such as the hippocampus, amygdala, and cerebral cortex, resulting in the weakening of connections, or synapses, between neurons (via Nature). By contrast, some studies have shown that the anti-inflammatory and antioxidant properties of CBD within marijuana can help treat various neurodegenerative conditions that affect memory, such as Alzheimer's disease and epilepsy. A 2019 review has even claimed that cannabis might prevent or slow down dementia.

The extent to which smoking marijuana underlies cognitive decline — or helps remedy illnesses that involve memory loss — requires further investigation. While long-term use of cannabis can have deleterious effects on memory, according to a brain-scanning study, the silver lining may be that these impairments are often temporary and even reversible within a few weeks of cessation.