Cannabis will likely soon be legally classified as medicine. But medicine for what?

The Drug Enforcement Administration (DEA) proposed rules earlier this year that would officially give cannabis status as a medication rather than an illegal narcotic – that’s exciting news for researchers, but will rescheduling mean that cannabis could soon move from the dispensary to the drug store?

Experts say it’s not that simple.

Peter Grinspoon, a physician, Harvard medical school instructor and author of the book Seeing Through the Smoke, says that the upshot of rescheduling will be “a little bit incoherent”.

Under the new rules, cannabis would be reclassified as a schedule III drug – meaning any cannabis-based medications would probably require FDA approval and a doctor’s prescription. This will mean it would still be more regulated than alcohol and tobacco, says Grinspoon, even though it is “safer by every metric”. Meanwhile, cannabis will continue to be available at state-legal dispensaries without the FDA’s signoff.

Related: Republicans use cannabis smell complaints as ‘excuse’ to oppose legalization, advocates say

The most important change is symbolic, Grinspoon says, because “the US government is once again admitting that [cannabis] is a medicine.” It’s currently very difficult to get permission from the federal government to do research on the cannabis plant. Grinspoon thinks rescheduling could make it easier to study medical cannabis by easing stigma as well as legal restrictions.

“Cannabis isn’t magically different from everything else,” he says. “It’s less harmful than opiates, but it still has harms, and if you use it, you should want to know the harms.” People on both sides of the debate “are going to be sort of forced to contend with reality”.

Grinspoon is particularly keen to see research on whether cannabis could actually fight diseases.

“Cannabis is very good at alleviating symptoms. We already know that. We know that it helps with chemotherapy-induced nausea and vomiting, we know that it helps with pain. I’m interested to know if cannabis can help modify the course of diseases versus just treat the symptoms,” he says. “Like in the test tube, cannabis is very good at treating killing cancer cells, but cannabis hasn’t been shown to cure cancer in humans yet, just in the test tube.”

Igor Grant – long one of a select few with authorization to study cannabis in a lab – thinks the drug could be especially useful for certain conditions that resist existing treatments. Grant is a psychiatrist and director of the Center for Medical Cannabis Research at the University of California, San Diego, established in 2000 to help fulfill the mission of California’s 1999 Marijuana Research Act. Rescheduling would mean those decades of research could benefit a much bigger group of patients.

“Neuropathic pain continues to be an important direction,” says Grant. It’s associated with many conditions including HIV infection, multiple sclerosis and spinal injuries, and is “difficult to treat, and really impairs quality of life. If you can’t sleep at night because of this condition, and the meds you’re taking are not very helpful, that’s bad.”

Jahan Marcu, author of the book Cannabis Innovations, on cannabis and hemp regulation, says that in order to get FDA approval, cannabis-derived drugs would probably need to either be synthetic or extensively refined.

There are already some FDA-approved medications on the market that are related to cannabis. Dronabinol, first approved in 1985 for chemotherapy-induced nausea as well as Aids-related anorexia, contains a synthetic version of THC.

More recently, the 2018 Farm Bill created the possibility for medications actually derived from the cannabis plant. It lifted restrictions on products that contain less than .3 % delta 9 THC, believed to be the plant’s most intoxicating component. So far, the FDA has only approved one cannabis plant-derived drug – Epidiolex, a pharmaceutical-grade formulation of CBD that treats rare seizures. Rescheduling could mean that the FDA approves similar products made from plant-derived delta 9 THC, although the agency rarely approves plant-derived drugs.

Even drugs that originally came from plants tend to be manufactured. “People figured out what were the active molecules, and then they figured out how to make those,” Grant says. Still, he is hopeful that the FDA’s approval of Epidiolex will mean that other cannabis plant-derived medications will be approved.

Marcu says this type of medication can “offer precise dosing and consistency but will lack the full spectrum of compounds provided by a crude extract”.

The FDA requires drugs to be precisely formulated to assure safety and consistency. Since the cannabis plant contains hundreds of different cannabinoids and terpenes, it’s unlikely that the FDA would ever authorize unrefined products, like the ones available in dispensaries.

Grinspoon says that separating out cannabis’s compounds hinders the “entourage effect” of all of them working in concert. He says that even though Aids patients have access to FDA-approved synthetic cannabis, many prefer the whole plant for this reason. He hopes for a more diverse array of cannabis-derived medicines, not just more formulations of its biggest components, CBD and THC. Many cannabinoids have not yet been researched much, but show promise.

“There’s one called THCV, which lowers appetite and blood sugar and increases insulin sensitivity,” he says. “I mean, that’s a pharmaceutical goldmine to try to dig into what each of those do and how we could exploit them medically. It’s just going to be sort of infinite.”