What is berberine, the supplement dubbed 'nature's Ozempic' on social media?

A dietary supplement called berberine is gaining momentum on social media for its weight loss effects, even being referred to by some as "nature's Ozempic," in reference to the popular drug that can help people shed pounds.

Users say berberine, which is found in a number of plants, including barberry plants, helps curb appetite and improve blood sugar levels, resulting in weight loss. Google searches for "berberine" began to increase at the end of March before they spiked in late May.

Berberine is rising in popularity as demand increases for medications like Ozempic and Wegovy, known for their weight loss effects.

Ozempic and Wegovy are part of a class of drugs called GLP-1 agonists, which mimic a hormone that helps reduce food intake and appetite. They are highly effective, but they are in short supply in the U.S. They are also expensive — around $1,000 or more out of pocket — and need to be prescribed by a doctor.

By comparison, berberine appears to be widely available online, and it usually ranges in price from $15 to $40 for a month's supply.

"You don't have to deal with a doctor, and it's going to be a lot less expensive," said Dr. Pieter Cohen, who researches supplement use at the Cambridge Health Alliance in Somerville, Massachusetts. "So from an advertising perspective, it's perfect."

But that doesn't mean berberine is effective, or safe, for weight loss. Here's what to know about it, including how well it works and whether it's safe.

Many of the claims about berberine haven't been verified by large, peer-reviewed studies — and the bulk of the research has been conducted in mice, not humans, experts say.

A meta-analysis of 49 studies published last year in the journal Frontiers in Nutrition found berberine may provide metabolic benefits in people, mainly for the heart, although there may be small benefits for weight loss.

"It's not a dramatic weight loss average for berberine," said Dr. Fatima Cody Stanford, an obesity medicine specialist and the equity director of the endocrine division at Massachusetts General Hospital in Boston. The studies show it is "between a quarter of BMI point to one BMI point, which is nowhere near what you see on average with semaglutide," she said, referring to the drug found in Ozempic. Stanford wasn't involved in the research.

For people in those studies, the optimal dose appeared to be 1 gram per day, Stanford said.

Cohen was more cautious about using the compound for weight loss.

Because dietary supplements aren't reviewed or approved by the Food and Drug Administration, they can be promoted for just about any health claim, Cohen said. Supplements can also contain inaccurate amounts of the compound or contain other ingredients that aren't listed on the label.

"An active pharmaceutical drug like berberine, it's not the kind of thing that you should just be taking willy-nilly," he said.

What's more, how the supplement supports weight loss — if at all — is largely unknown, Cohen said.

"People are saying it is like metformin, but it is not," said Dr. Holly Lofton, the director of the weight management program at NYU Langone Health, referring to a medication people with diabetes use to lower their blood sugar levels. She said she isn't recommending berberine for weight loss.

Medications derived from plants aren't uncommon, Cohen said. Highly effective drugs, including aspirin and morphine, come from plants.

Known side effects of berberine in humans include nausea and vomiting, Stanford said. In animal studies, it appeared to enlarge the liver and the kidney and reduce the number of white blood cells, which fight off infections. Larger studies would need to be conducted to know whether there are any serious side effects in humans.

Stanford said she would recommend speaking with a doctor before taking berberine as a part of a weight loss regime. It may not be safe for pregnant women, she added.

"These don't go through any FDA approval or regulation," she said. "You might work with someone that has some knowledge, whether it be an MD or naturopathic physician."

If there are any side effects, stop taking the medication, she said.

Cohen said that despite the potential benefits for weight loss, it's "not worth the risk."

In fact, he said, if people do experience weight loss using berberine, they should stop taking it immediately and talk to a doctor. "That could suggest that something is wrong with the product you’re taking and you might be exposed to something that's more dangerous than berberine," he said.Follow NBC HEALTH on Twitter & Facebook.

Berkeley Lovelace Jr. is a health and medical reporter for NBC News. He covers the Food and Drug Administration, with a special focus on Covid vaccines, prescription drug pricing and health care. He previously covered the biotech and pharmaceutical industry with CNBC.