Microdosing is more popular than ever. Here's what you need to know.

Once considered taboo, microdosing has made its way to the semi-mainstream.

Elon Musk recently reported that he microdoses ketamine for the treatment of depression, while Prince Harry said mushrooms and ayahuasca helped him through the grief of losing his mother.

It has also piqued the interest of physicians and researchers, as more evidence is emerging that microdosing can improve mental health. A recent study found psilocybin may help cancer patients with depression and anxiety.

You may have questions.

What exactly is microdosing? Is it safe? Is it legal? We spoke with Dr. Shannon Eaton, a neuroscientist and Assistant Teaching Professor of Psychology at Arizona State University, to learn everything you need to know about microdosing.

What is microdosing?

When you take a “recreational” dose of drugs commonly microdosed, like ketamine, psilocybin or LSD, you may experience hallucinations or dissociation.

Microsing is when you take a dose well below the threshold of experiencing hallucinations and other subjective effects. So why would you microdose at all?

“The whole idea is you're taking a very small dose – like a tenth of what you would use to feel anything. So you're not getting the same dissociative effect. You're not getting the same visual or auditory hallucinations that you might see with serotonergic drugs (drugs that impact the transmission of serotonin, like psilocybin or LSD.) You're not getting that same, ‘I am completely out of my body, and I can't move’ effects that you see with higher doses of ketamine,” Eaton explains.

“But what you are seeing with these very small doses is maybe a slight shift in mood,” she emphasizes.

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Is microdosing safe?

There are risks when you take any drug or medication, however, microdosing is safest when it is done under the guidance and supervision of a healthcare professional. This is considered therapeutic and not recreational. In this setting, healthcare professionals can respond in an emergency, and you know exactly what you’re taking and the dose.

Is microdosing legal?

Ketamine is legal with a prescription from a doctor, but most therapies (with the exception of Spravato, or esketamine, a nasal spray) have not been FDA-approved. Oregon recently made psilocybin legal. Most other hallucinogenic drugs aren’t legal, however, more research is being done on their therapeutic use, which could change laws in the future.

Attitudes around microdosing have been shifting – and evidence suggests that may be for the better. However, there are still risks associated with taking hallucinogenic drugs unsupervised, so talk to your doctor if you think you may benefit from microdosing.

More: Sharon Osbourne says ketamine helped her depression. Is this the next big trend?

This article originally appeared on USA TODAY: What is microdosing? Ketamine, mushrooms and what you need to know