Advocates on both sides of the debate over legalizing marijuana are skeptical that the Food and Drug Administration will recommend reclassifying marijuana out of the highest drug schedule and say little would change even if it did.

Douglas C. Throckmorton, deputy director for regulatory programs at the FDA’s Center for Drug Evaluation and Research, told lawmakers last month that the agency is analyzing whether marijuana should continue to be categorized as a Schedule I substance, spurred by citizen petitions received by the Drug Enforcement Administration. Under the Controlled Substances Act, drugs are classified into five schedules based on their potential for abuse and other criteria, with Schedule I considered to be the most dangerous.

But Dan Riffle, former director of federal policies for the Marijuana Policy Project, said it’s very difficult to obtain marijuana for research because the National Institute on Drug Abuse has a monopoly on the supply. He said he has no doubt the eight-factor analysis being performed by the FDA will yield the same result as those before it.

The agency conducted analyses at the DEA’s request in 2001 and 2006 and recommended that marijuana remain in Schedule I, according to Throckmorton’s testimony.

Kevin A. Sabet, cofounder of Project SAM, which opposes marijuana legalization, said the FDA is looking at the issue because a legalization advocate is forcing the issue. It’s “fantasyland” to think marijuana will be rescheduled, he said, citing the science on the issue and disputing that obtaining the drug for research is a problem.

Even if it was moved to Schedule II, Sabet added, it wouldn’t matter because the penalties are a separate matter.

Riffle agreed, calling the idea that marijuana should be rescheduled a “red herring.” Rescheduling wouldn’t do anything because it would still be illegal to possess the drug under federal law, he said.

At last month’s hearing, Throckmorton said he couldn’t say when he expects the FDA’s analysis to be complete. The agency makes a recommendation to the Department of Health and Human Services after consulting with NIDA, he noted, and then that recommendation gets sent to the DEA.