Shares were already near multiyear lows. But, thanks to today's 20% tumble in response to the exit of a high-profile board member, WW International (WW 10.06%) stock hit its lowest-ever price on record. And the bottom may not have been hit yet.

Oprah Winfrey stepping down

Media mogul Oprah Winfrey is the director in question. She and the company entered into a partnership in 2015 that was expected to reignite interest in the then-waning weight loss brand, when it was still called Weight Watchers. The association had little lasting impact, though. The company's revenue as well as the stock's value are still both well below their 2012 peaks.

Winfrey says she will finish out her current term as director but will not seek to be re-elected to the board when elections are held in May. She adds that her 1.1 million-share stake in WW International will be donated.

The twist? Winfrey is also using an unnamed weight loss medication, which has been suggested as a serious threat to other weight-management tools like WW's. The company's press release announcing Winfrey's decision explains this move will help "eliminate any perceived conflict of interest around her taking weight loss medications."

Just another reason to steer clear of WW International

Make no mistake; WW International was already on the defensive before anti-obesity injections like Eli Lilly's Zepbound and Novo Nordisk's Wegovy were approved by regulators. Consumers have been using a wide range of other approaches and platforms to lose weight, ranging from diet foods, calorie-counting apps, and, increasingly, prescription and over-the-counter medications, and more. Investors have little reason to expect meaningful growth from WW International in the foreseeable future, if ever again.

When a high-profile influencer like Oprah Winfrey separates herself from a company because she's using one of these alternatives, though, it speaks volumes about the organization's future and the marketability of its products. Bargain-minded investors won't want to view Thursday's steep sell-off as a buying opportunity.