Start-up investor Li Jiang just turned 30, and now he can't stop thinking about his own mortality. For Jiang, who's based in San Francisco, living longer isn't just about eating healthy and exercising regularly. Last month, he cryogenically froze his stem cells, in the hopes of someday injecting them back into his body. Jiang is one of the earliest testers of Forever Labs, which extracts and stores young adults' stem cells to potentially combat age-related illnesses like arthritis and heart disease. The company has the ambitious plan to counter "aging itself." Forever Labs is a graduate of the start-up accelerator program Y Combinator and has raised $2 million in funding to expand its service to more states. Jiang, a former investment banker who worked on health-care deals, is also an early investor in the start-up. It's not a cheap endeavor. Forever Labs charges $7,000 for a plan that includes the procedure and lifetime storage. Jiang says that's the price tag for longevity. "If you are able to extend your life by even five years, I mean I think you would pay something to do that," he said.

Forever Labs CEO Steven Clausnitzer and investor Li Jiang Katie Brigham | CNBC

But this is unprecedented work, and the market is so nascent that doctors and scientists are still researching how the frozen stem cells can even be used in the future. Not everyone is convinced that it's worth the time and money to store these cells. Agnieszka Czechowicz, an assistant professor of medicine at Stanford focusing on stem cell transplantation, said it's unclear if regulators will approve any potential therapies that would rely on these samples. There's also the risk that the samples might not be large enough to be used in any meaningful way, and uncertainty about what would happen if Forever Labs were to fail, as many start-ups do. Despite the many hurdles associated with private stem cell banking, Czechowicz said she's excited about the prospects and "the evolving research that may open opportunities to use such cells."

'Tremendous potential'