Formaldehyde sounds scary because it is for dead bodies. But it is also produced in our natural cellular respiration. Clearly "the dose makes the embalming fluid" but groups who want to scare people about diet soda whisper about its presence. And it is present, in levels that will be carcinogenic if you drink 7,000 sodas per day. More recently its presence in nicotine vaping liquid was being touted.

Given the medical marijuana fad, not to mention the rush for recreational use, it was only a matter of time before someone noted the presence of formaldehyde in it. What's the real story? There is a huge difference between hazard and risk. The risk is determined by exposure. The risks of cigarettes are huge while the risks of e-cigarettes and other smoking cessation techniques are still basically random chance.  Marijuana, on the other hand, has similar toxic chemicals to cigarette smoke. The formaldehyde is likely the least concern.

The journal merits some suspicion, which makes it all the more bold they published it at all. Alternative medicine fans are far more likely than the evidence-based community to believe anything found in nature is more beneficial than real medicine. The Journal of Alternative and Complementary Medicine authors say they found that one inhalation of the vapor produced by heating polyethylene glycol (PEG) 400 put an individual at risk for 1.12% of the daily formaldehyde exposure limit. The researchers tested four thinning agents commonly used to vaporize cannabis oil-propylene glycol, PEG 400, vegetable glycerin, and medium chain triglycerides and the levels of three compounds that have the potential for serious health effects in the vapors produced when the agents were heated to the temperature needed to vaporize cannabis oil.

"Users should be aware of potential harms of using vaporized cannabis oils and know what thinning agents are used in the products they consume, as we learn more about their effects when vaporized and inhaled," says Leslie Mendoza Temple, MD, Clinical Assistant Professor, The University of Chicago and specialist in Integrative Medicine, NorthShore Medical Group, Glenview, IL.