Cannabis legalization has become increasingly popular among Americans, even those who don’t partake, and states are taking notice. Legal, regulated cannabis sales offer many benefits to individuals and state and local governments including increased tax revenue, access to safer products, and reduced activity and dependence on the unregulated black market. Legal controlled substances often come with age limits, and these can vary on a state-by-state and case-by-case basis. How old do you have to be to smoke weed? Let’s take a closer look.

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Why do states have age limits on cannabis use?

Like alcohol and tobacco, cannabis remains a controlled substance in the 33 states that have legalized it for medical or recreational use. Policymakers place age limits on these substances in an attempt to promote safe and responsible use. Alcohol’s only widely-accepted medical uses are as a disinfectant, antiseptic, and antidote to methanol poisoning in cases where fomepizole is not available. Tobacco, on the other hand, is responsible for over 3 million deaths per year worldwide. Despite the myriad medical applications of cannabis, many states have based their cannabis age limits on existing alcohol and tobacco laws. The long-term effects of cannabis use in minors have not been well-researched and many agree that it is best to err on the side of caution. 

What is the legal age to use recreational marijuana in the US?

While cannabis remains federally illegal in the United States, the states which have legalized recreational cannabis sales, including Alaska, California, Colorado, and Michigan have set the legal age to purchase cannabis at 21.

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This age limit mirrors the legal drinking age nationwide. The federal legal age to purchase tobacco was recently raised from age 18 to age 21 as well. The underlying logic behind setting the recreational use age limit at 21 is, presumably, that if a person can be trusted to use alcohol responsibly at 21, the same rings true for cannabis. 

Should the legal age be changed?

There are two major schools of thought regarding the appropriate age to begin using cannabis. Those who advocate for higher age limits argue that the human brain continues to develop until the age of 25, and that mind-altering substances can negatively impact brain development. Although alcohol is an acutely mind-altering substance, the “developing brain” argument is not reflected by the legal drinking age of 21.

Those who believe the legal age for recreational cannabis use should be lowered to age 18 argue that the ramifications of higher age limits could be more detrimental than helpful. In a survey of more than 42,500 students across the United States, researchers found that 30.3% of 12th graders reported daily cannabis use.

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Without regulated access to cannabis, young people are likely to seek out illicit means of acquiring cannabis. Not only does this fuel the black market, it also means there is no regulation of product safety. Furthermore, if caught and convicted, the implications of a criminal record can have long term negative effects on everything from housing to job prospects. 

At what age can you use medical marijuana?

Many states that offer a medical marijuana program set the minimum age to apply at age 18. This is the age at which one is considered legally an adult in the United States and may make legal decisions and enter contracts without parental consent.

It stands to reason that this is the age where an adult can advocate for their own medical treatment as well. A doctor’s recommendation based on qualifying conditions is still generally required. What about younger patients who suffer from the same qualifying conditions? The laws regarding medical cannabis use by minors vary by state.

In states including Nevada, Michigan, and Hawaii, there is no age limit to apply for medical cannabis provided the patient receives a medical recommendation. Other states allow minors to use medical cannabis if an adult parent or guardian gives consent and registers as the minor’s caregiver.

Due to the existing opioid crisis, a growing number of doctors are in favor of prescribing cannabis to minors for pain relief in situations where highly-addictive opioids might otherwise be applied, such as in the event of sports injuries or when recovering from surgery. Some states have further restrictions on the medical use of cannabis by minors.

Legal age for cannabis use in Canada

Cannabis has been legal in Canada since 2018, and the Canadian Task Force on Cannabis Legalization and Regulation has recommended that the legal age for recreational cannabis use be set at a minimum of 18 years of age.The legal drinking age is similar, set at 18 or 19 years old, depending on the province.

Provinces have the discretion to set their own age limits on recreational cannabis use. For example, the legal age for cannabis use in Alberta is 18 years, while legal age in Quebec is 21. Other provinces and territories have set the age limit at 19. Travelers are expected to follow the local laws when in another province, so 20-year-olds may legally possess cannabis in Alberta, but not Quebec.

Legal age in other countries

Cannabis acceptance and use has not just increased in the United States and Canada. At least 30 countries have legalized the use of medical cannabis.

Others have decriminalized cannabis in small amounts or made certain concessions regarding the use of cannabis. Let’s take a look at some examples.


In 2014, Uruguay was the first country to legalize recreational cannabis.

This country’s early adoption of recreational cannabis was aimed at reducing the amount of drug-related organized crime. The legal age to consume cannabis in Uruguay is 18 years. Consumers are required to join a registry and are only permitted to purchase small amounts(10 grams per week). They may grow up to 6 plants in the home.

The Netherlands

Amsterdam coffee shops are some of the most ubiquitous symbols of cannabis consumption in the world, but cannabis laws in the Netherlands aren’t as free-wheeling as you may think. In fact, it is illegal to produce, possess, sell, import, or export drugs in the Netherlands.

Coffee shops are the sole exception, and the shops are not permitted to sell more than five grams per customer per day. Cannabis is considered a “soft drug” as compared to “hard drugs” such as heroin, and coffee shops are intended to be a safe consumption space. Minors under the age of 18 are not permitted to enter coffee shops, even if they do not intend to consume cannabis on the premises.

For consumers in the United States, we hope for a day when federal decriminalization will lead to uniform cannabis laws. Will doctors, lawmakers, and consumers ever agree on how old you have to be to smoke weed? Only time will tell.