March 26 (UPI) -- Most legal marijuana products may be too strong for pain relief, according to a study published Thursday in the journal PLOS ONE.
Despite research showing the benefits of marijuana for pain management, the analysis suggests that more than 90 percent of legal products offered in medical dispensaries because they contain higher levels of tetrahydrocannabinol, or THC, than is needed for treatment.
THC is the main psychoactive compound in marijuana that causes intoxication.
"We know that high-potency products should not have a place in the medical realm because of the high risk of developing cannabis-use disorders, which are related to exposure to high THC-content products," the study's lead author, Dr. Alfonso Edgar Romero-Sandoval, associate professor of anesthesiology at Wake Forest School of Medicine, said in a press release.
According to Romero-Sandoval, multiple studies have shown that marijuana products containing up to 5 percent of THC are sufficient to reduce chronic pain with minimal side effects.
In recent years, as more and more states and countries have legalized it, marijuana-based products -- ranging from flower and vapor cartridges, to oils, edibles and salves -- have come to be seen as an alternative to stronger prescription pain medications, like opioids, which are highly addictive.
An estimated 60 to 80 percent of medical marijuana users take the product for pain relief, Romero-Sandoval noted.
Although research documenting the effectiveness of marijuana as a pain reliever is limited, the evidence to date has shown that it offers at least some benefit, according to a review published last month in the journal Clinical Medicine Insights: Arthritis and Musculoskeletal Disorders.
For the new study, the researchers evaluated THC and CBD content in 8,505 products from 653 legal dispensaries in California, Colorado, Maine, Massachusetts, New Hampshire, New Mexico, Rhode Island, Vermont and Washington. They compared the potency of products from state to state, including the difference in medical and recreational products.
The team found that most of the products from medical dispensaries contained more than 10 percent THC and that many had 15 percent or more, the same levels found in products at recreational dispensaries.
Researchers say this is problematic because a higher concentration of THC can increase risk for dependency, but also for developing tolerance more quickly -- which means increasing concentrations of the compound may be needed to achieve the same level of pain relief.
"It can become a vicious cycle," Romero-Sandoval said. "Better regulation of the potency of medical marijuana products is critical. The FDA regulates the level of over-the-counter pain medications such as ibuprofen that have dose-specific side effects, so why don't we have policies and regulations for cannabis, something that is far more dangerous?"