At Stiiizy, the best-selling cannabis brand in America, the goal is explicit: producing powerful and cheap marijuana.

Inside its Los Angeles headquarters, crews dust joints with concentrated THC, the intoxicating component of cannabis. They package pocket-size vape cartridges that promise “the highest potency possible.” On its website, the company declares that “it has never been easier (or quicker) to get silly high for an affordable price.”

Dispensaries operating under the brand of another leading company, Cookies, have promoted “powerful medical benefits,” including “cancer fighting” qualities. A cannabis-infused chocolate bar was, until recently, described as containing properties “beneficial to those suffering” from glaucoma, bacterial infections and Huntington’s disease, a devastating genetic illness.

More than a decade after states began legalizing recreational marijuana, businesses are enticing customers with unproven health claims, while largely escaping rigorous oversight. A New York Times review of 20 of the largest brands found that most were selling products with such claims, potentially violating federal and state regulations. And as companies compete, potency has gone up — with some products advertised as having as much as 99 percent THC — and prices have gone down.

“What we’re seeing is really a race to the bottom,” said Matt Zehner, a senior analyst at Brightfield Group, which tracks the legal cannabis industry.

Some executives said their companies are trying to navigate complex rules while satisfying their customers. Stiiizy’s co-founder and chief executive, James Kim, said in an interview that many are heavy users in search of a good deal, something he had sought as a broke “pothead” in his early 20s. “This is why I believe we’re very successful,” he said.