There are a lot of people out there that think that marijuana smoke and tobacco smoke are the same, and that both are equally bad for you. But is that true? What does science have to say about the matter? More and more states are legalizing medical marijuana, but banning smoke-able forms of cannabis due to fears that marijuana smoke is the same as tobacco smoke. Minnesota and New York are examples of that. One of my heroes, Paul Armentano of NORML, recently wrote about this topic. Below are some excerpts from his article:

Writing in the Harm Reduction Journal in 2005, noted cannabis researcher Robert Melamede explained that although tobacco smoke and marijuana smoke have some similar chemical properties, the two substances possess different pharmacological activities and are not equally carcinogenic. Specifically, he affirmed that marijuana smoke contains multiple cannabinoids – many of which possess anti-cancer activity – and therefore likely exerts “a protective effect against pro-carcinogens that require activation.” Melamede concluded, “Components of cannabis smoke minimize some carcinogenic pathways whereas tobacco smoke enhances some.”

Consequently, studies have so far failed to identify an association between cannabis smoke exposure and elevated risks of smoking-related cancers, such as cancers of the lung and neck. In fact, the largest case-controlled study ever to investigate the respiratory effects of marijuana smoking reported that cannabis use was not associated with lung-related cancers, even among subjects who reported smoking more than 22,000 joints over their lifetime. Summarizing the study’s findings in The Washington Post, pulmonologist Dr. Donald Tashkin, Professor Emeritus at the David Geffen School of Medicine at UCLA, concluded: “We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use. What we found instead was no association at all, and even a suggestion of some protective effect.”

According to a 2015 study conducted at Emory University in Atlanta, the inhalation of cannabis smoke, even over extended periods of time, is not associated with detrimental effects on pulmonary function, such as forced expiratory volume (FEV1) and forced vital capacity (FCV). Assessing marijuana smoke exposure and lung health in a large representative sample of U.S. adults, age 18 to 59, they maintained, “The pattern of marijuana’s effects seems to be distinctly different when compared to that of tobacco use.” Subjects had inhaled the equivalent of one marijuana cigarette per day for 20 years, yet did not experience FEV1 decline or deleterious change in spirometric values of small airways disease.

While tobacco smoking is recognized as a major risk factor for the development of COPD – a chronic inflammation of the airways that may ultimately result in premature death – marijuana smoke exposure (absent concurrent tobacco smoke exposure) appears to present little COPD risk. In 2013, McGill University professor and physician Mark Ware wrote in the journal Annals of the American Thoracic Society: “Cannabis smoking does not seem to increase risk of chronic obstructive pulmonary disease or airway cancers… Efforts to develop cleaner cannabinoid delivery systems can and should continue, but at least for now, (those) who smoke small amounts of cannabis for medical or recreational purposes can breathe a little bit easier.”