Is smoking weed bad for you?

Cannabis may be entering the mainstream and getting incorporated into wellness routines, but many of us still have questions about the risks and benefits of consuming the herb. Are there risks to smoking marijuana? And if so, what are they? 

Here, we'll look at current scientific research and parse out the hard evidence about marijuana's effects from unfounded assumptions.

Understanding the basics: How cannabis affects your body

Before diving into a detailed discussion of whether or not marijuana is bad for you, let's cover the basics. For this discussion, it is helpful to understand where the effects of marijuana come from, how it interacts with the human body, and how it creates the various effects for which it's known.

The cannabis plant naturally creates hundreds of chemicals, and marijuana smoke contains nearly all of them. Cannabinoids are the most important ones when it comes to understanding how marijuana affects the human body.

Cannabinoids are chemical compounds that interact with the human body's endocannabinoid system (ECS), which has receptors throughout the central nervous system and which is linked to a variety of functions such as mood, appetite, sleep, and more.

Over 100 different cannabinoids

The marijuana plant creates well over 100 different cannabinoids. When you consume cannabis, different cannabinoids bind to different receptors in your ECS. The interactions between cannabinoids and your endocannabinoid receptors are what produce the range of effects you may experience — whether that's high, sleepy,  hungry, calm, paranoid, or a variety of other possibilities.

In general, tetrahydrocannabinol, commonly known as THC, is recognized as the dominant cannabinoid produced by the cannabis plant. THC is responsible for the bulk of marijuana's psychoactive properties — it's the stuff that gets you high.

Cannabidiol, commonly known as CBD, is the other predominant cannabinoid. In general, people think of CBD as the other side of THC's coin. Whereas THC is responsible for the psychoactive effects of marijuana, CBD is responsible for most of the reported health and wellness effects of cannabis. CBD also counteracts and mellows out a lot of THC's more intense and potentially unpleasant effects.

Beyond THC and CBD: other cannabinoids and terpenes

While THC and CBD are generally seen as the most prominent and important cannabinoids in the cannabis plant, they're not the full story. Marijuana smoke contains literally hundreds of other chemicals that all play a role in producing the effects of marijuana.

In addition to the 100-plus cannabinoids found in marijuana, the plant also produces different chemicals called terpenes. While cannabinoids are found in cannabis, terpenes are actually produced by a number of plants, most notably citrus fruits, pine trees, herbs, and other aromatic plants. Terpenes are used to create essential oils that are used in fragrances, foods, drinks, and household products  These chemicals are where marijuana, and any other terpene-producing plant, gets its smell and flavor.

Current research suggests that cannabis produces its most potent, powerful, and noticeable effects when all these chemicals interact together in tandem inside your body. This is called the entourage effect. Because of the entourage effect, cannabinoids and terpenes have more pronounced effects when you consume them all together at the same time, as opposed to consuming an isolated cannabinoid or terpene on its own.

Is marijuana smoke dangerous? Lung health and the risks of smoking

While we wish the answer was as clear cut as “yes, smoking weed is bad for you” or “no, smoking weed isn't bad for you,” the truth is a bit more complicated.

First, let's look at smoking as a consumption method. Whenever you combust plant material — whether it's cannabis, tobacco, or anything else — toxins called polyaromatic hydrocarbons form. Polyaromatic hydrocarbons exist in both tobacco and marijuana smoke and exposing yourself to those toxins is one of the biggest and most obvious risks of smoking weed.

man smoking joint
Research shows that smoking cannabis doesn't have the same risks as smoking cigarettes.
Photo by: Gina Coleman/Weedmaps

But research shows that smoking marijuana doesn't have the same risks as smoking cigarettes. While smoking weed to excess may lead to respiratory issues (exacerbating lung infections, bronchitis or, in severe cases, COPD), or otherwise compromise lung function, there has been no causal link found between smoking weed and cancer, one of the biggest risks associated with tobacco smoke. In fact, research shows that some compounds in cannabis may slow the growth of cancerous tumors.

Smoking anything, including smoking marijuana, has potential risks. There's no way around it — inhaling smoke, no matter what it's from, is never good for lung health. But beyond this baseline level of harm, research shows that marijuana smoke has far fewer risks than tobacco smoke, and, to date, there's been no link found between marijuana smoke and cancer.

What the American Lung Association says about smoking marijuana

The American Lung Association, one of the leading professional organizations of lung doctors and experts, weighed in on the question of whether or not smoking marijuana is bad for lung health.

In an article titled Marijuana and Lung Health," the American Lung Association attempts to lay out some groundwork for what it believes about marijuana use. Ultimately, the American Lung Association draws similarities between marijuana and tobacco, stating that both marijuana and tobacco smoke cause damage to lungs. It also states that smoking marijuana could be linked to other conditions, including lung disease and several conditions related to the immune system.

"Due to the risks it poses to lung health," the group writes, "the American Lung Association strongly cautions the public against smoking marijuana as well as tobacco products."

Avoid smoke for safer consumption

Given that smoke in your lungs will always introduce a base level of harm to your body, it might be a good idea to explore other methods for consuming cannabis. If you can avoid smoking, you can tap into the potential health benefits of cannabis without the detrimental effects of inhaling smoke.

Other ways to consume marijuana include edibles, tinctures, and topicals. While things like edibles and tinctures allow you to avoid putting smoke in your lungs, you should also be aware that these consumption methods can sometimes produce very different effects than smoking.

That's because your body metabolizes cannabis differently based on how you consume it. When you smoke weed, THC, CBD, and all those other cannabinoids and terpenes enter your bloodstream by way of your lungs, which is a relatively direct pathway. But when you eat cannabis, these chemicals are processed through your stomach and digestive system, which is more of a roundabout process than simply inhaling marijuana smoke.

For many consumers, the differences in how your body metabolizes cannabis leads to some notable differences in the effects it produces. First, it takes longer to get high when you consume edibles. Smoking weed, which puts cannabinoids directly into your bloodstream, produces effects that set in very fast, within a few minutes. But the effects of eating marijuana take a bit longer, typically around 30 to 45 minutes or up to two hours. Second, many people experience much more intense and longer-lasting highs when they eat cannabis.

If you go for edibles over smoke, pace yourself. If you don't feel high right away, don't keep eating more and more. If you do that, by the time it finally sets in, you might have so much THC in your system that you move beyond a pleasurable experience and into a paranoid, unpleasant one. Take a dose of 2 milligrams of THC or less, then wait and give your body time to metabolize it. If, after at least two hours, you still don't feel high enough, try eating 3 milligrams and repeat the wait-and-observe process.

Is vaping a good alternative to smoking?

Vaporizing marijuana, whether in the form of vaping flowers, THC cartridges, or dabbing, is a bit of a controversial subject when it comes to lung health. Many argue that vaping is an effective way to avoid smoke, and is, therefore, a safer, healthier mode of consumption than smoking. Others maintain that putting vapor into your lungs may carry its own set of risks. Ultimately, because vaping is a new technology, we simply haven't had enough time yet to see how it might affect people in the long run.

gummy edibles
If you're concerned about experiencing respiratory side effects, try other consumption methods, like edibles, tinctures, or vaporizers.
Photo by: Gina Coleman/Weedmaps

Are there safer ways to smoke marijuana?

If the only way you will ever consume marijuana is to smoke it, consider using a bong or some other type of water pipe. When you smoke out of a water pipe, the smoke passes through a chamber filled with water.  

In a bong or similar pipe, the water acts as a filter, pulling unwanted particles and contaminants out of the smoke and helping cut down on the amount of toxins. When the filtered smoke finally hits your lungs, it will have fewer contaminants and unwanted particles, thereby offering a cleaner and potentially healthier way to smoke marijuana.

Additionally, water pipes tend to cool the smoke, giving your lungs a smoother smoking experience. To make the marijuana smoke even cooler and smoother, incorporate an ice catch into your bong. This adds another layer of cooling to the process, as the smoke travels through and around ice cubes after being filtered by the water. You can also add ice to the bong water.

Potential negative side effects of marijuana consumption

People consume marijuana in different ways, for different reasons, and have different experiences. Many people smoke weed and encounter no negative side effects whatsoever. Some find tremendous relief from conditions like PTSD or chronic pain. These people would probably say smoking weed is not bad for them, and is in fact, good for them. Maybe even essential.

But others smoke weed and have a different experience. Marijuana can make some people feel anxious, tired, or unmotivated. In extreme cases, they may develop cannabis use disorder. For those people, smoking weed probably isn't the best choice.

Every consumption method, including smoking, has potential side effects. According to current research, some of the negative effects associated with smoking cannabis include:

There is also research into the links between cannabis consumption and brain function. Much of what this research has found suggests that younger people, particularly those 21 and younger, should avoid marijuana consumption. This is primarily because, in terms of negative impacts on the brain, marijuana appears to be most destructive when the brain is still developing.

The risks associated with smoking weed increase based on the frequency and duration of use. For people who smoke weed moderately, the benefits (particularly for patients using cannabis for medical reasons) typically outweigh the risks.

Can you overdose on cannabis?

The short answer is no. According to the Centers for Disease Control and Prevention, nobody has ever had a fatal overdose from cannabis. Certainly, as outlined above, it is possible to have unpleasant experiences and effects from pot, but you cannot die from consuming too much marijuana.

There was an official investigation into this question back in 1988. After looking into the matter, researchers concluded that marijuana smokers "would theoretically have to consume nearly 1,500 pounds of marijuana within about fifteen minutes to induce a lethal response." The bottom line for these researchers: "in practical terms, marijuana cannot induce a lethal response as a result of drug-related toxicity."

Is marijuana a gateway drug?

One of the common reasons people give for why cannabis might be bad for you is the idea that it's a "gateway drug." This theory asserts that as people build up a tolerance to marijuana, they move on to harder and harder drugs, chasing more intense highs. Essentially, the argument is that marijuana use will lead to other, much more harmful drug use.

Interestingly, there is actually a growing movement that sees cannabis as a way out of addiction rather than the pathway into addiction. Specifically, researchers have noted correlations between access to medical marijuana and lower rates of opioid addiction. This suggests that cannabis might offer people a safer way to deal with pain so that they never have to rely on addictive opioids, or that cannabis can provide people an alternative way of treating pain so that they can stop using opioids.

Similarly, some drug rehab centers have begun pioneering the use of cannabis as a means of helping wean people off of other, more addictive drugs. The idea here is that cannabis can provide a safer, more manageable high, giving people the experience of being high without the risks of addiction or overdose.

Potential positive health effects of marijuana smoking

So far, we've outlined the potentially negative effects of consuming cannabis. But it's also important to note that, for many cannabis consumers, there are just as many, if not more, positive health effects of marijuana use.

Marijuana's possible ability to provide health effects and wellness benefits is attested by the fact that the huge majority of states in the US now have legal medical marijuana. And in nearly all of those states, there is a fairly large list of health conditions deemed suitable for marijuana medicine.

While additional research is needed to ascertain the full range of conditions medical cannabis may help treat, some of the health conditions that often quality for medical marijuana treatment include:

  • Chronic pain
  • Glaucoma
  • Several forms of cancer
  • Appetite loss, and medical treatments that lead to appetite loss
  • Anxiety
  • Depression
  • Epilepsy
  • Crohn's disease and other digestion-related ailments
  • Sleeping disorders
  • A number of mood disorders
  • Inflammatory bowel syndrome (IBS)
  • Post-traumatic stress disorder (PTSD)

In addition to these and other formally recognized conditions for which medical marijuana can be effective, many marijuana smokers turn to CBD for a range of health benefits. This typically includes treating stress, anxiety, inflammation, and using it as a general wellness aid. CBD is especially attractive to consumers who want the calming benefits of cannabis without having to also experience a psychoactive high.

While some research points to positive potential medical benefits of cannabis, the fact that it's illegal at the federal level and was illegal in nearly all states for decades has stunted good, quality research on human subjects. The studies that do exist show great potential but more research, specifically rigorous clinical trials, are necessary to convince the skeptics of cannabis' healing potential. 

Who should avoid smoking marijuana?

There are certain groups of people who should avoid cannabis, including:

  • People under the age of 21. There is a mountain of evidence that using cannabis while the brain is still developing can lead to serious adverse outcomes, so children, adolescents, and young adults under the age of 21 should abstain from smoking weed or consuming cannabis. 
  • People with psychotic disorders and/or a family history of psychotic disorders. Cannabis may exacerbate symptoms of a psychotic disorder. If you struggle with a mental illness like schizophrenia or psychosis (or you're at high risk due to a family history of such disorders), it's recommended that you avoid cannabis altogether.
  • Pregnant or breastfeeding women. While there is some debate around the safety and potential risks of smoking marijuana while pregnant or breastfeeding, the research still hasn't reached any definitive answers. For the sake of the child's health, most medical professionals recommend erring on the side of caution and abstaining from cannabis use during pregnancy and breastfeeding.
  • People with cannabis use disorder. If you find yourself struggling with dependence on cannabis or your cannabis use is interfering with or negatively impacting your life, abstinence is often necessary. 
  • People on certain medications. Cannabis may interact with certain pharmaceutical drugs. If you've been prescribed blood thinners, blood pressure medication, or any other medications to help manage or treat a cardiac condition, it's important to speak to your doctor about smoking weed and confirm whether there are any potential risks or interactions between cannabis and your prescribed medication. If you're on any psychiatric drugs, it's also important to talk to your doctor about whether smoking marijuana while taking your prescribed drugs can cause any negative side effects. If you're thinking about trying CBD and you take medications with a warning not to consume grapefruit, you should also talk to your doctor.

While the majority of people in the above-mentioned groups should avoid marijuana, there are exceptions, particularly when cannabis is prescribed for medical reasons. Again, the only way to determine whether smoking weed is good or bad in any particular situation is to evaluate the risks and benefits, apply them to yourself and your situation, and come to a personal conclusion for yourself and your health.

Why do people still assume marijuana is dangerous?

Even though common perceptions of cannabis are changing as marijuana becomes legal in more places, some still harbor the belief that cannabis is dangerous and bad for people's health. However, a review of available research makes clear that the answer isn't that simple. Research shows that there are some potentially negative outcomes from consuming cannabis just as there are many potentially positive outcomes.

Given this, why is there still such a deep assumption that cannabis is bad? Why is marijuana policy built on the assumption that marijuana is bad and has no benefits — even when evidence suggests otherwise?

The truth is that many of the sources that helped create and propagate the idea that cannabis is dangerous are, let's say, less than trustworthy. Here's a quick history of how cannabis came to be viewed as dangerous and why this is still so often the assumed truth about marijuana.

A quick history

Cannabis was not always viewed as a dangerous drug, nor was it always illegal. Up until the late 1800s and early 1900s, cannabis was used fairly widely and in a variety of applications, including many curative and medicinal applications.

Things began to change around the turn of the century, as various efforts to regulate and restrict the use of cannabis at the local and regional levels began to take hold. The first national regulation of cannabis arrived with the Marihuana Tax Act of 1937.

In an interesting demonstration of how widely accepted cannabis was at the time, the American Medical Association (AMA) actually opposed the Marihuana Tax Act of 1937, arguing that the new taxes and regulations introduced by the act would fall particularly heavily on doctors who were regularly using cannabis in their practices and who were prescribing cannabis to their patients.

Despite the AMA's opposition, the Marihuana Tax Act of 1937 passed, introducing a burdensome set of fees, taxes, and restrictions on marijuana, which effectively made marijuana illegal at the national level.

The criminalization of marijuana accelerated from that point on. In October 1937, only a few months after the Tax Act passed, cannabis arrests and convictions began. And over the next few decades, US lawmakers passed a series of increasingly strict anti-cannabis laws. These maneuvers eventually led to full-on federal prohibition and marijuana's current status as a Schedule I controlled substance, meaning it has no medical value and a high potential for abuse.

Scare tactics or science?

Marijuana prohibition laws claim to be about public safety and health. These laws assume that cannabis is bad, dangerous, unhealthy, and therefore needs to be outlawed. But a deeper dig reveals that those ideas about weed are not grounded in anything scientific or health-related, but are instead the result of campaigns aimed at creating fear.

The Marihuana Tax Act of 1937 was drafted and pushed aggressively by Harry J. Anslinger, the first commissioner of the Federal Bureau of Narcotics. Anslinger is often viewed as an early architect of the war on drugs, given his role in criminalizing cannabis and other drugs.

In order to drum up support for the Marihuana Tax Act, Anslinger leveraged racist ideas to create fear of cannabis and of marijuana smokers. "Marijuana is the most violence causing drug in the history of mankind," he told the US Congress. "Most marijuana smokers are Negroes, Hispanics, Filipinos and entertainers. Their satanic music, jazz and swing result from marijuana usage." He made many other racist claims about marijuana. The Marihuana Tax Act of 1937 was pushed through primarily on these types of arguments, not any evidence that cannabis is dangerous or harmful.

Anslinger's focus on creating fear about cannabis, rather than seeing what scientific data had to say, set a pattern that has been followed for decades to come, leading all the way up to the present day. For example, a top advisor to Richard Nixon admitted that the war on drugs, which the Nixon administration ratcheted up in the late 1960s, was designed to target political dissidents and black people, not because there was any scientific or medical evidence that cannabis or other drugs are dangerous.

Bottom line

From the perspective of consumption, smoking marijuana carries some risk, but not nearly as many risks as smoking cigarettes. Marijuana use has the potential to be both helpful and harmful, healthy and unhealthy, “good” and “bad.” People who smoke marijuana could be at higher risk for certain health problems, specifically conditions related to the lungs. It all depends on a variety of factors, including your health, your history, and the way you consume cannabis. Weigh the risks and benefits and make the decision that's right for you. 

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The information contained in this site is provided for informational purposes only, and should not be construed as medical or legal advice. This page was last updated on June 22, 2021.