What Happens When You Smoke Weed

man smoking a joint

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There are a number of different things that can happen to you when you smoke weed. In addition to the immediate short-term impact of the substance, smoking pot can also have long-term effects on both your mind and body. These effects can vary from person to person.

Different ways of taking the substance can also play a role in how it impacts your body. Smoking marijuana is one of the fastest routes of administration that produces rapid changes in your brain and body. In order to understand the possible risks of marijuana, it is important to first understand what happens to your body when you smoke weed.

Short-Term Effects of Smoking Pot

The reaction you may have when trying marijuana can vary dramatically based on many factors. Some people report not feeling anything at all when they smoke marijuana. In other cases, people report feeling relaxed or "high."

Short-Terms Effects on the Body

The effects of using marijuana can be unpredictable, especially when it is mixed with other drugs, research shows. You may feel relaxed on the drug, but other things you might not be expecting with pot use can include rapid heart rate and other unpleasant symptoms.

  • Accelerated heart rate
  • Bloodshot eyes
  • Dry mouth
  • Loss of coordination
  • Swollen eyelids

Short-Term Effects on the Mind

As with any drug or substance that can alter perception, logic, and usual behavior, there are several short-term hazards of using marijuana from impaired driving abilities to memory loss.

  • Anxiety and paranoia
  • Difficulty in thinking
  • Impaired memory
  • Lack of attention and focus
  • Learning difficulties
  • Poor driving skills

Some people who use marijuana report having sudden feelings of anxiety and paranoid thoughts, and this might be caused by trying higher-potency marijuana, according to the National Institute on Drug Abuse.

Research also shows that regular use of marijuana is linked to an increased risk of depression, anxiety, and a loss of motivation or drive. You may feel "dopey" on the drug, which is when you begin to lose interest in activities that you might have previously enjoyed or you may lose the ability to grasp concepts easily.

Long-Term Effects of Smoking Weed

Any drug that is taken over a prolonged period of time can have an effect on your health. Several of the physical barriers that can occur range from infertility problems to overall brain function.

  • An increased risk of developing lung, head, and neck cancers
  • Decreased sperm count in men
  • Heightened risk of infections, especially the lungs
  • Inability to shift attention normally
  • Inability to understand complex information​
  • Irregular menstruation in women
  • Lack of motivation
  • Poor short-term memory recall
  • Respiratory problems

Some studies suggest that the impact that marijuana has can depend on the age at which a person began smoking marijuana and for how long they used the substance.

Smoking vs. Vaping

In addition to smoking and being consumed in edibles, marijuana can also be inhaled by vaping heated oil smoked through an e-cigarette. There is little known about the negative health effects of vaping THC products, but a number of serious lung injuries have been attributed to vaping. The CDC recommends that people should not use any vaping products containing THC, the psychoactive chemical in marijuana.

Why Reactions to Weed Vary

The National Institute on Drug Abuse reports that marijuana can affect each person differently according to their own body chemistry and the type of pot used. Some people can use weed and never have any negative reactions while others may try it and get entirely freaked out by the experience.

Factors that influence how you respond when you smoke weed include:

  • Marijuana's strength (amount of active ingredient THC): Studies have found that the marijuana available today is much different in terms of potency compared to what was generally available in the 1960s when the use of the drug became widespread in the United States. Today's strains of the plant contain much more of the active ingredient in marijuana: tetrahydrocannabinol or THC, researchers say. That makes today's weed much more potent than that smoked by the hippies and flower children of the Woodstock generation.
  • Previous experience with the drug: If you have used marijuana regularly, it may mean that you have developed a tolerance to the substance. This means that it requires more of the drug to produce the same effects that you initially felt.
  • How it's taken (smoked versus ingested): Smoking marijuana produces rapid effects because the substance begins to affect the brain quickly. When ingested, it takes longer to have an effect.
  • Whether alcohol or other drugs are taken too​: Taking other substances can have an effect on how marijuana impacts your mind and body. Such substances can interact to heighten the adverse effects of both substances.
  • Your biology (genetic makeup): Genetics as well as other biological factors can affect how a person responds to and metabolizes a substance. Age, hydration levels, body mass, metabolism, sex, and frequency of use may all play a role. For example, women tend to metabolize THC at a somewhat slower rate than men, which may impact how the drug affects them.

Effects of Edibles

As recreational marijuana becomes legal in more states in the U.S., more edible products containing marijuana are hitting the market. When marijuana is ingested it is absorbed by the body more slowly and the effects can last longer and be stronger.

Emergency rooms have reported an increase of cases involving negative reactions to marijuana and many of those cases can be traced back to edible marijuana products.

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4 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Institute on Drug Abuse. Marijuana: Drug facts. Revised December 2019.

  2. Partnership for Drug-Free Kids. Marijuana. Updated August 15, 2018.

  3. National Institute on Drug Abuse. What are marijuana's long-term effects on the brain? Published July 2020.

  4. CDC. Outbreak of lung injury associated with the use of e-cigarette, or vaping, products. Updated February 25, 2020.