An emerging trend in the world of over-the-counter health products are vitamins that you don’t swallow or chew, but that you inhale, a distinction that creates a gray area in how they are used and regulated. An FDA official has clarified to Inverse the agency’s evolving view on the products that are increasingly popular but pose more questions than answers to curious consumers.

The FDA has applied more scrutiny recently to vaping or use of so-called “e-cigarettes,” which speaks to its surging popularity — particularly among teenagers. FDA Commissioner Scott Gottlieb has gone so far as to call vaping “an epidemic”, and the organization’s estimates suggest that its use among teens has risen from 1.5 percent in 2011 to 11.7 percent in 2017.

FDA spokesperson Jeremy Khan tells Inverse that vitamin vaping liquids will probably not be regulated as supplements, because you can’t eat them, you inhale them.

“Under the Federal Food, Drug, and Cosmetic Act, a dietary supplement must, among other requirements, be intended for ingestion,” Khan says. “Accordingly, a vitamin product for inhalation cannot be legally marketed as a dietary supplement.

Instead of filling a vape pen with an e-liquid containing nicotine, some are filling them with vitamin based concoctions. The first of these “vitamin vaping” companies launched in 2016 but now, scientists have emerged in publications like Men’s Health, Elle and The New York Post, commenting on on potentially dangerous health effects off swapping out a vitamin pill for an e-liquid.

Despite skepticism of vitamin vaping from the scientific community, it remains unclear how the FDA will regulate these products that look a lot like vitamin supplements, but are inhaled through vaporizers — which are technically tobacco products.

Vaping Vitamins: Caught Between Two Worlds

Vaping liquids that claim to include vitamins fall between two regulatory worlds: the supplement world and the world of tobacco products. It’s possible that e-liquids containing vitamins but no tobacco could be treated as dietary supplements, which the FDA does not regulate before they go to market. But the vaporizers themselves might also fit the definition of tobacco products and must undergo public health and safety evaluations before marketing.

“Generally, FDA would consider any vitamin vape product that is intended to affect the structure or function of the body or that is intended to treat, mitigate, prevent, or cure disease to be an unapproved new drug,” Khan says.

It seems that the FDA will likely not be treating these e-liquids like supplements — implying that they may be subject to more stringent oversight

Companies like Vitamin Vape and Breathe, both market e-liquids that contain no nicotine at all. The FDA’s policy on regulating tobacco products stipulates that the definition of a “tobacco product” includes components, parts or accessories which includes vape pens, and e-cigarettes. From that standpoint, vitamin vape companies may be subjected to regulation of the devices. The status of the liquids isn’t set in stone:

“It is possible that a disposable, closed-system device that contains an e-liquid with truly zero nicotine (or synthetic nicotine) would not be regulated by the FDA as a tobacco product, if it is not intended or reasonably be expected to be used in such a fashion,” Kahn says.

He adds that the FDA will likely make these determinations on a case-by-case basis. It seems like the regulation of these vitamin vape companies will vary greatly by company.

As this regulatory landscape develops in the meantime, there’s still plenty of work out there suggesting that it’s not a great idea to vape vitamins anyway.