The US government's cool with weed now—as long as it's fake.

Early this month the Food and Drug Administration approved the first ever liquid formulation of dronabinol, which is synthetic tetrahydrocannabinol, or THC, the main psychoactive compound in cannabis.

Sold under the brand name Syndros, this new drug is likely to be classified under the Controlled Substances Act as Schedule III, indicating accepted medical use and low to moderate potential for abuse. Real cannabis, a Schedule I drug, is federally illegal, like heroin. The FDA is hoping that synthetic THC drugs like Syndros might offer a narrow, more pointed approach to treatment than the full impact of its herbal counterpart.

Dronabinol itself is old news: It's the generic name for Marinol, a synthetic cannabinoid pill first approved in 1985. Marinol is classified as Schedule III, but the pharmaceutical's delayed onset and potentially dysphoric side effects have rendered it far less popular than real cannabis.

The pharmaceutical company Insys Therapeutics manufactures both Marinol and Syndros. Both have been approved to treat AIDS patients with appetite loss and cancer patients struggling with nausea. Insys boasted that Syndros is the single FDA approved dronabinol solution for oral use, according to the press release. Already, there are approximately 9,500 dronabinol prescriptions. And Insys is hoping to convert many of them to Syndros.

"I think it is really important to understand the difference between a preparation that has gone through clinical development and one that hasn't."

However, the new drug may not be that different from its older sibling, Marinol, according to Los Angeles-based medical marijuana physician Dr. William Eidelman. He said some patients prefer Marinol, while others like traditional medical marijuana.

"Some people want the Marinol prescription for the reason that having the prescription gives it an additional level of legal acceptability under federal law," Eidelman said. Still, he added, a basic drug test doesn't differentiate between THC from dronabinol products and THC from real cannabis.

Eidelman, who recommends both cannabis flower and prescribes Marinol to his patients (medical marijuana cannot be "prescribed" because it's not FDA-approved), said Syndros' liquid form might absorb more quickly than a pill, and help doctors more easily manage dosage.

Yet the drawback to drugs like Marinol or Syndros is the absence of the "entourage effect", said medical marijuana physician Dr. Perry Solomon, chief medical officer of San Francisco-based telehealth startup HelloMD. This effect describes the synergistic reaction all the chemicals in the cannabis plant have to one another. So when only one chemical is extracted from the plant—or in the case of dronabinol, when only one cannabinoid like THC is present—the medicinal effect is weaker.

"Most of our patients like having the full spectrum of the effect of the medication," Solomon said. Especially, he explained, since most patients have a combination of symptoms.

Watch HIGH COUNTRY, Motherboard's 2014 journey to the heart of the Silicon Valley of weed.

Dronabinol-based pharmaceuticals resemble products that are allowed in more limited medical marijuana states, such as New York. With a ban on whole-plant cannabis, New York patients are confined to using manufactured cannabinoid formulations in the form of pills, tinctures, sublingual strips, medicated patches, and vaporizable oils. Some of these products have an array of cannabinoids, but others have cannabidiol (or CBD, a non-psychotropic compound in cannabis), without THC and so a reduced entourage effect.

But dronabinol's more sterile and focused application makes it easier to obtain FDA approval.

"The companies that make the synthetic versions do all the clinical development for the products. There is a pharmaceutical preparation," said Catherine Jacobson, director of clinical research at Tilray, a Canadian medical cannabis company. "I think it is really important to understand the difference between a preparation that has gone through clinical development and one that hasn't. We would like to do research on whole plant extracts. One of the holdups is the lack of safe, reliable, consistent products that are not pharmaceutical products."

Patients don't often know if their medical cannabis will be consistent from batch to batch, or free from contaminants, said Jacobson. And drugs that don't go through rigorous clinical development cannot obtain FDA approval, she added. Still, it's a vicious cycle because cannabis is illegal under federal scheduling, which makes research on it more difficult.

"The scheduling disparity is frustrating to everybody is who trying to do research on the plant and understand the physiological effects of the plant and its chemical components," Jacobson said.

Doctors like Eidelman also struggle with the legal disparity between the scheduling of synthetic and that of organic cannabis. "One never likes the government to act in stupid ways," Eidelman said. "Politics is politics. It oftentimes gets in the way of medicine and this is one example."

Correction: An earlier version of this story erroneously said Syndros had been classified as Schedule III. The drug has not been scheduled yet, but is expected to be Schedule III based on previous similar drugs.

This originally appeared at https://www.vice.com/en/article/3dapvv/fda-approves-liquid-synthetic-weed-syndros