Sure, CBD is everywhere. But it hit the Sundance Film Festival with full force only in January, when Charlotte’s Web, a leading purveyor of the substance — the Uber of CBD, if you will — hosted a three-day party, lines out the door, in a converted store and restaurant on Main Street in Park City, Utah.

It was envisioned by the seven brothers behind the company: Josh (43), Joel (39), Jesse (37), Jon (36), Jordan (34), Jared (32) and J. Austin (27), all with the last name Stanley. Five of them were attending Sundance with their proud mother, Kristi Stanley Fontenot, 65, hosting screenwriters, film editors and the like dressed in casual sweaters, jeans and snow boots, at panel discussions on the future of cannabis and alternative healing and at parties serving CBD-infused cocktails.

One night there was a $175 10-course dinner. All the dishes, including the cured black cod to the hazelnut chocolate crunch cake, contained Charlotte’s Web CBD.

Thomas Pierce, a 32-year-old film producer and C.E.O. of an entertainment marketing agency, was among those bingeing on the offerings. “I attended a private dinner for 50, a happy hour event with CBD beer and tacos, and a late party sipping on delicious CBD cocktails,” Mr. Pierce said. “I was in my happy place.”

Josh Hetzler, a producer of “Before You Know It,” a film premiering at Sundance, worked with Charlotte’s Web to distribute CBD his entire cast and crew.

The brothers were running around the space, letting their personalities shine.

Josh Stanley, the eldest and nerdy one, roped guests into technical, scientific discussions about CBD. “We use liquid chromatography to test all the levels of the cannabinoids in the field,” he told this reporter. “We perfected the art of the oxymoron. The whole plant is standardized.” (A 30-something woman nearby was overheard telling her friend that he looked like the lead singer of a boy band.)

Joel Stanley, the chairman of the company, ran around handing out necklaces that carried bottles of their farms’ soil and taking selfies. He slicked his hair back for the occasion and proudly wore a fluffy gray-and-white-checkered wool sweater. “My brother bought them for all of us in Mexico City,” he told a group congregated around him. “I don’t know why my brothers aren’t wearing theirs.”

J. Austin, the youngest, was there with his boyfriend Mitch Clough. (They live together in Denver and have a dog named Little Arthur Weasley.) He kept coming up to his mother, hugging her and making fun of her for how much she was loving Sundance. “He’s the fun one,” she said.

Jon, the bearded one (though he has shaved since), mostly hung out a table with his fiancée, Katie, holding hands and savoring the food. And at a party later Jared was drinking cocktails with his mother at a wooden table at the back, shyly surveying the scene.

With their personalities differ, they all agreed on one thing: They hated the larger-than-life banner of all seven of them posing on the hemp farm hanging on the wall of the party.

“I think most of us are intimidated by it,” Josh said. “We tried to take it down. We can’t handle it.”

“I think we are a marketer’s dream because we have a family dynamic,” Joel said. “They feel like we’re a great big sandbox. We’re, like, O.K. …”

“It’s kind of crazy,” J. Austin said. “I’m the wallpaper for a Sundance party.”

There were more guests at the party than in the brothers’ entire hometown.

Roasting the Marshmallows

They described growing up in poverty in a tiny community named St. Louis, Okla., which has a current population of 158. The four eldest were raised in a two-bedroom trailer with no drinkable water. Even when they moved into a larger house, they said, five boys shared one bed — a water bed with no headboard or frame, just a mattress. (They also have four sisters, Jennie, 41, Joy, 29, Julee, 23, and Jensyn, 21, who aren’t involved in Charlotte’s Web’s daily operations, though Julee worked in customer service the first few years and Jennie is an investor in the company.)

Nick Ferguson, 35, who has known the Stanley family since he was in fifth grade, said almost every time he goes to a bar or restaurant with one of the brothers now, a stranger approaches them.

“They are a good-looking group of dudes, girls have always taken notice,” Mr. Ferguson said. “But now even guys will come up and say, ‘Are you one of the brothers?’ Sometimes they just want to say hi, but other times they want to talk at length about Charlotte’s Web and my buddy has to say, ‘I’m trying to have dinner with my friends right now.’”

Kristi Mahaffey met Rich Stanley through a mutual friend. They were students at Kansas State University and married less than a year from the date they met. “He was very charming and very, very charismatic,” she said. “He kind of had this Tom Selleck look that was hard not to fall for.”

Mr. Stanley was committed to Christianity and God (less so his sales job, which he was continually quitting), so they moved to St. Louis to help grow a Southern Baptist church. With four children and one on the way, all they could afford was the two-bedroom trailer. Mrs. Fontenot said she had to drag all the children to the church every morning to collect drinkable water.

Her mother, Signa Mahaffey, whom the family calls Gammy, helped them move into a three-bedroom home in nearby Shawnee. There, five more children were born. They had tap water, but often couldn’t afford to pay the electricity bills.

“It would get turned off, and Mom would tell us it was campfire time,” Josh Stanley said. “We would get so excited and pull out the candles and roast the marshmallows.”

Jordan remembered how stressful it felt when the car broke down constantly. Jesse asked to be dropped off blocks from school because he was embarrassed by that same car. As a 5-year-old Jared collected pennies to buy gallons of milk because his brothers told him it would fill him up like a meal.

At the film festival, Josh was joking with his mother about how many younger siblings he has. “I am a professional diaper changer,” he said. “I can whip up a formula. I can even nurse.”

The first child was named Joshua David, from the Bible. For the next one, a girl, they couldn’t decide if they should name her Jenny or Danny. “The coin chose Jenny, and it set the J names in motion,” Mrs. Fontenot said.

The brothers fought growing up (and still do). “Josh and I have broken each other’s noses,” Joel Stanley said. At the dinner, Joel was laughing at Josh for being long-winded. Josh was making fun of Joel’s outfit.

If the boys wanted to do anything special, like go on a ski trip with their youth group, they had to raise their own funds. They started a yard-raking business by putting up signs all over town that said, “Rake your yard the easy way. Hire me.” Jared Stanley was particularly skilled at selling candy bars door-to-door, even going into office buildings. “He must hold the world record,” Mrs. Fontenot said.

Josh Stanley remembers using money he made from a paper route to buy pillows from a thrift store so he could sleep on the floor instead of the crammed bed. “One day I just had enough,” he said.

“When I was 13, Joel was 18, and he was basically working full time while a senior in high school,” said Mr. Ferguson, the family friend. “Even though I was young I remember thinking that was a sacrifice.”

He never met Rich Stanley, who left in 1997 when the youngest child, Jensyn, now 21, was a year old. He is now 66 and living in Denver, where he works as an Uber driver. The sons generally talk about him respectfully if coolly.

Still, they rented him a home when they made enough money, and on the phone Rich Stanley said he is a loyal customer. “I use Charlotte’s Web five to six times weekly,” he said. “It has made a noticeable difference in my cognitive thinking and in my joint health.”

In 2007, Kristi married Steve Fontenot, an oil-drilling consultant. But by that point, the boys were on their way to forging their own fortune.

In 2010, Josh asked his mother to come with him to look at office spaces in the Denver area. Since college he had been working with developmentally disabled children in group homes. He had read up on medical marijuana, and he wanted to open his own dispensary.

His mother’s distressed reaction: “Pull the car over right now.”

She later read papers on the topic and then slowly got on board. It wasn’t like the family was oblivious to marijuana. “Josh definitely did pot growing up in high school,” Mrs. Fontenot said. “I knew he was doing it, but it wasn’t disruptive, and I was so busy having babies.”

Josh moved into the warehouse so he could work on his project full time, sleeping on a sleeping bag on the floor. But at the time there was no medical marijuana bill. There was only one constitutional statute, the one he operated on, that said one caregiver could grow six plants for one patient.

By Josh’s own account, he was serving tens of thousands of people. “I knew that is not what the law intended,” he said. At one point the governor’s office called Josh’s lawyers in, and, as Josh recalled, said that he had beaten the system for now but would be in handcuffs soon.

Josh responded by starting the first 501c4 in Colorado to lobby for a medical marijuana bill. Luckily for him, Bill 10-1284 passed in 2010, helping pave the way for regulated medical marijuana sales.

One day he arrived at the dispensary to find protesters, many from a right-wing Christian coalition group holding signs saying Jesus was against him. No banks would lend him money.

At the time, Joel was in Texas working for an oil company. Jon was traveling the world. Jordan was in Colorado clearing the forests for fire prevention as a chain saw operator. Jared was working at a bar. Jesse was playing basketball at the University of Colorado at Colorado Springs. J. Austin was still in high school.

One night, most of them were in Denver for a concert by John Prine, a country folk singer-songwriter. They gathered at their mother’s house and listened to Josh lay out his vision and arguments. Everyone except J. Austin (still in high school) joined Josh’s endeavor.

At that point Joel assumed the role C.E.O. of the company. Most growers of cannabis at the time were searching for strains that contained high percentages of THC, the extract that makes people high. But the Stanleys were searching for plants that contained more CBD, the extract that purportedly heals.

They crossbred multiple varieties to get one that contained 22 percent and named the products derived from it after their first patient, Charlotte, a little girl with Dravet syndrome, a very rare and destructive form of epilepsy that caused her to have hundreds of seizures.

The brothers were still focused on medical marijuana as a business, but that changed in August 2013 when CNN’s Sanjay Gupta did a special on their success with Charlotte. Fifteen thousand families reached out to them in the next month, they said, and the company decided to focus on CBD. Charlotte’s Web was born.

According to the company, sales have tripled every year since 2015. It currently ranks No. 1 in the world for sales of hemp-based CBD, according to New Cannabis Ventures, an information platform focused on the cannabis industry. In September, in Canada, the company raised $100 million in an I.P.O.

A Toke and a Smile

There is nothing sexy about the Charlotte’s Web lab in Boulder, Colo. It’s a factory operation, filling up to 50,000 bottles of CBD oil a day.

In the lobby there are framed signs attesting to the company’s quality control. The most fun part is a little plaque with a pig on it that Charlotte’s Web’s bank made for it to celebrate the I.P.O. There aren’t even pictures of the good-looking brothers.

But this will probably change soon.

In December the 2018 Farm Bill passed in the United States Congress, legalizing CBD across the United States. As long as it contains less than 0.3 percent THC, and therefore doesn’t get you high, you can grow it, cultivate it, charge for it, even ship it across state lines (there are some restrictions for quality control. Also, some places are declaring where it can be distributed. New York City, for example, just took away the right of food vendors to sell it.)

“The moment the 2018 farm bill passed, I knew it was the moment to join Charlotte’s Web,” said Eugenio Mendez, who left his job as global vice president of marketing of water, enhanced water and sports drinks at Coca-Cola to become Charlotte’s Web chief growth officer.

While Charlotte’s Web isn’t legally allowed to declare any medical benefits, the company said it gets hundreds of letters a week from people saying it works for Parkinson’s, lupus, PTSD and opioid withdrawal. There are people giving it to their pets.

Then there are the casual users, people taking oil at parties to prevent hangovers the next day. Others take it in the morning, because they believe it keeps them calm, alert and feeling good. Some think it helps with anxiety and insomnia.

Mr. Hetzler suggested his film crew try it to ease the physical pain of making a movie. “I remember being approached by one of our crew members after a long day of rigging lights and moving gear,” he said. “He told me the CW balm worked incredibly well.”

It’s a strange reality when the same product is being used for both life’s biggest medical challenges and to prevent hangovers. But that’s where we are with CBD, said Dr. Rachna Patel, the author of “The CBD Oil Solution,” who began prescribing medial marijuana in 2012.

“Typically the way it works is you have a medicine, there is research done on it, scientists figure out what it works for, then people use it,” she said. “It’s the opposite with CBD. People are using it, and then they are like, ‘It works for this,’ and now science needs to study it.”

CBD may be hype. It may be placebo. It may be a miracle cure. Legislation could shut it all down at any moment. But in the current culture, the Stanleys have a huge advantage.

Since the beginning of 2018, Charlotte’s Web has experienced a 60 percent growth in sales online. The product is now found in 3,700 stores across the United States. The company is forecasting revenue growth of $120 to $170 million in 2019, up from $15 million in 2016.

Each brother has contributed something different to its success. “One of the best public speakers I’ve ever heard in my life is my older brother Josh,” Joel said. “When we have a TED Talk, we may write the content, but he gives it. Jesse is one of the funniest people I’ve ever met in my life. He’s hilarious, but he’s also creative so he does the marketing. Jon is the dead sexy one. Jon, Jordan, they take on the grunt of planting, learning how to deal with pests, teaching the farmers what to do. Jared is the most valuable operator. He should have been Forbes 30 under 30, but now he’s too old. He’s the one that does all the scaling. J. Austin, he handles scheduling, opportunities and events. Everyone loves him.”

And each has his own vision of how to use his new wealth. Jon, who is engaged and expecting his first child, wants to learn a new language. Jared, married with a 4-year-old, has bought his first home. J. Austin, who has a long-term boyfriend, had his eyes on a Toyota F4 Cruiser but instead bought an Infiniti.

Jordan, married with two children, dreams of sharing his land with the community by throwing some kind of outdoor events. Josh, divorced with one child, owns a vacation property in Costa Rica. So does Jesse Stanley (still single!). Joel is busy keeping track of his three children, all with different hobbies, who travel between his house and that of his ex-wife.

Charlotte’s Web next plans to build a tourist destination where fans from all over the world can interact with the product. Like at the Guinness Factory in Dublin or the Avery Brewery, five miles from Charlotte’s Web’s lab, people will be able to learn about CBD, try it out and see how it is made. But please don’t have the misapprehension this will be some kind of Stoned-henge.

“Not everyone wants to be strung out,” Joel said. “I know I don’t.”