The White House on Monday removed a major bureaucratic barrier that has long hindered scientific research into the medical properties of marijuana.

Marijuana research is no longer required to be subjected to the Public Health Service (PHS) review, which was introduced by the Clinton administration to require individual review of all applications for marijuana research through the Department of Health and Human Services.

"The Obama administration has actively supported scientific research on whether marijuana or its components can be safe and effective medicine," said Mario Moreno Zepeda, spokesman for the White House Office of National Drug Control Policy, reported The International Business Times. "Eliminating the Public Health Service review should help facilitate additional research to advance our understanding of both the adverse effects and potential therapeutic uses for marijuana or its components."

The language of the now-suspended PHS review protocol said its purpose was "to facilitate the research needed to evaluate these pending public health questions by making research-grade marijuana available for well-designed studies," but marijuana supporters have long claimed the review process served to thwart research rather than facilitate it, according to the Drug Policy Alliance. They point to the fact that not even LSD or heroin research required a PHS review.

A bipartisan group of lawmakers had been working to have the requirement lifted, and even opponents of marijuana legalization joined in the reform effort, reported The Huffington Post.

"This announcement shows that the White House is ready to move away from the war on medical marijuana, and enable the performance of legitimate and necessary research," said Bill Piper, director of Drug Policy Alliance's Office of National Affairs. "This is progress, but the White House should also end the [National Institute on Drug Abuse's (NIDA)] unique monopoly on marijuana production, and allow private entities to grow marijuana, thus facilitating even more important research."

Since 1968, the University of Mississippi has been the only producer of federal marijuana, meaning researchers looking to conduct federally-approved tests on medical marijuana only have one source for obtaining cannabis.

NIDA recently increased funding to the university with a $68.6 million contract to expand its marijuana production to 30,000 plants, and with PHS review now out of the way, activists have turned their attention to what they say is the other major hurdle preventing research.

"The two biggest hurdles to marijuana research have been the PHS review and NIDA's monopoly on the supply of marijuana available for research purposes," said Dan Riffle, director of federal policies for the Marijuana Policy Project, according to IBT. "Now that one of those unnecessary barriers has been removed, we hope the second will undergo serious scrutiny. In fact, the Senate will be holding a hearing Wednesday regarding marijuana-related research, and we expect there to be some tough questions about NIDA's monopoly."

Marijuana is currently the only Schedule 1 drug prohibited from being produced by private laboratories, reported Al Jazeera. Being on the federal list of Schedule 1 substances means that the government considers it to have no medical value, despite owning a patent specifically highlighting its antioxidant and neuroprotectant properties.

Twenty-three states and the District of Columbia disagree with the official federal position on marijuana and have legalized the medicinal use of the plant.