Amy Ryan was panicking about her savings when she went online for advice. It was April 2020, and the stock market had plunged, draining a nest egg that she had built up over the years.

Ms. Ryan, a 43-year-old sales engineer from Wales, had dumped her portfolio in the crash and was afraid of losing even more. Looking for guidance, she found Kevin Paffrath, a prolific finance influencer who discussed the economy and investing on his Meet Kevin YouTube channel.

“At the time, I was not really well educated in buying and selling shares,” she said, adding that she felt reassured that Mr. Paffrath had about one million followers. “I trusted this guy.”

Social media is an appealing way for inexperienced people like Ms. Ryan to learn how to manage their investments. Content creators are branding themselves as money experts, endorsing a range of financial products from credit cards to cryptocurrencies, and earning a sleek moniker: fin-fluencers.

But a growing number of them have faced accusations of promoting high-risk assets, hyping “pump-and-dump” schemes or simply sharing unqualified advice. Regulations can be unclear or hard to enforce, especially across international borders.

Ms. Ryan had considered herself to be a savvy saver. When the markets began recovering from the Covid crash, she was terrified that she had been rash in selling her portfolio. She paid $532 for Mr. Paffrath’s “Stocks and Psychology” course and mirrored his lead in buying shares in companies that he believed were lucrative. She moved her cryptocurrency into BlockFi, a cryptocurrency lender that Mr. Paffrath promoted.