Justin Bieber, Martha Stewart and more promote cannabis use: Experts weigh in on THC vs. CBD

What do Martha Stewart, Jaleel White (aka Steve Urkel) and Justin Bieber have in common? They're all in the cannabis business.

In October, Bieber partnered with Palms, a Los Angeles-based cannabis company, to create "Peaches" pre-rolled joints, a nod to his hit single from "Justice." In the track, featuring Daniel Caesar and Giveon, Bieber sings about cannabis in the chorus: "I got my peaches out in Georgia… I get my weed from California."

"Palms is excited to introduce a high-end line of indoor pre-rolls celebrating Justin’s song, Peaches," reads a statement on the company's website. "With this limited edition pre-roll collaboration, Justin & palms are proud to be supporting the Last Prisoner Project and Veterans Walk and Talk."

"Weed was something that I felt people tried to make me feel bad for enjoying," Bieber told Vogue about the collaboration. "But I’ve now found a place in my life for weed products that have been beneficial in my human experience."

He joins the many celebrities, including Snoop Dogg, Stewart, Jay-Z and Seth Rogen, who have joined the industry in recent years and are making bold statements with their products. Stewart's self-named brand of CBD gummies claims to "make wellness an easier choice, every day," and Rogen's Houseplant strain of THC promises to give a "smooth, warm and calming experience."

These lofty product claims may be seen as marketing ploys in an increasingly competitive industry, but experts say there can be wellness benefits to some of these products.

Here's what they told us about marijuana and CBD in its various forms ahead of 4/20, an unofficial day that celebrates cannabis culture.

What's the difference between THC and CBD?

THC (Tetrahydrocannabinol) and CBD (Cannabidiol) are both chemicals known as cannabinoids found in the marijuana plant, but the two have differing effects and legal restrictions in the U.S.

"THC is (a cannabinoid) that has psychoactive properties, not that it's not healthy for you but it does get you high, unlike CBD," says Craig Henderson, CEO of Extract Labs, a Colorado-based company that specializes in extracting CBD from hemp plants for products.

CBD's chemical compound doesn't alter a person's mental state and can be harvested from the same place as THC, but it is mostly taken from the hemp cannabis plant.

More: CBD products are popping up in stores near you. Here's what you need to know about them

THC is what's typically known as weed or pot and is legal recreationally in 15 states. Some states allow it to be used medicinally under a doctor's supervision.

Why are celebs getting involved?

As more states legalize marijuana, more eyes are turning toward the industry. Willie Nelson, Gwyneth Paltrow and most recently "Crazy Rich Asians" actor Jimmy O. Yang have lent their names to cannabis products.

Each of their brands promise different results. Kristen Bell's Happy Dance CBD skincare says the products provide "a little more calm," while "Family Matters" actor Jaleel White says his "Purple Urkel" brand is dedicated to celebrating the "many medical breakthroughs" of cannabis.

But those who have been in the industry a little longer than these big-name endorsers say it's a different type of green catalyzing interest.

More: Celebrities high on marijuana businesses

More: Martha Stewart partners with marijuana producer Canopy Growth to create hemp-derived goods

"Money is why they're getting involved," says Henderson. "If you're a new CBD company, you haven't been around for four or five years, or just a cannabis company in general, how do you start off strong? You come in with a bunch of money, you bring on a spokesperson that already has a big name for themselves."

Where is recreational marijuana legal?

In March, New York became the 15th state to legalize marijuana in the United States. Other states include:

• Alaska

• Arizona

• California

• Colorado

• Illinois

• Maine

• Massachusetts

• Michigan

• Montana

• Nevada

• New Jersey

• Oregon

• Vermont

• Washington

Are there wellness benefits to CBD, THC?

Dr. Patricia Frye, who works with patients in the D.C. area who are interested in cannabis treatments, recommends CBD for those who live in states where marijuana is not legal.

Frye says both CBD and THC can help with sleep, anxiety, metabolism, stress and appetite.

"These cannabinoids are so helpful, (because) people are starting to move away from a lot of pharmaceuticals," she says.

There are still plenty of unknowns when it comes to CBD.

The FDA has approved the use of the drug Epidiolex, which contains CBD, for specific cases of seizures and epilepsy. The FDA-approved drug was placed in the "least restrictive" category of controlled substances by the Drug Enforcement Agency, meaning it's in the same category as cough medicine Robitussin AC.

“But overall, it’s a lot safer than anything else you’d be using if you’re using it instead of opioids for pain or Ambien to help you sleep or instead of benzodiazepine for anxiety," said Dr. Peter Grinspoon, a Harvard Medical School professor and a primary care doctor at Massachusetts General Hospital.

Does CBD have side effects?

Dr. Leeta Jussila, a practitioner who specializes in cannabis, says that everyone's system is different, so the way people absorb CBD differs. She recommends new users consult with health care providers and closely track how small doses of the chemical effect them.

"They could get a headache. Sometimes people say, 'I feel funny,' but you’ll never overdose on cannabis. You'll just start to detox," she said. "CBD is an oil, fat, lipid. Some people might get diarrhea. I’ve had one person get nausea, dry mouth or dizziness. But it depends on the quality of the product."

Frye and Grinspoon both caution those looking to try CBD to do their research about the products they are purchasing.

"You have to be careful with purchasing CBD because like the nutritional supplement industry, it's not well regulated," Frye says. "There are some very fine products out there and then there's a lot of junk out there. So people have to be careful."

“I’ve had patients have what seems like a pretty dramatic effect beneficially, and I’ve had other people say, ‘Why did I just waste $60 on this? It didn’t do anything,’” Grinspoon said. “It’s very variable. It’s complicated by the fact that it’s not that regulated, so you have to be a savvy shopper to even be sure that you get the right amount of CBD that you’re ordering.”

Grinspoon said it is important to look for a certificate of assurance when shopping for products.

“Don’t just take their word for it. You know, if you go into a gas station, you’re not necessarily going to get good CBD," he said.

More: Why is CBD on the rise for wellness products?

More: What is CBD oil? Separate facts from fiction to learn the truth about CBD

This article originally appeared on USA TODAY: CBD, THC, marijuana, pot. Experts explain wellness benefits for 4/20