Investors weighed political scrutiny and unproven health claims as Tylenol’s maker faced renewed controversy, sparking volatility in Kenvue’s stock.
U.S. President Donald Trump on Monday linked autism to both childhood vaccines and the use of Tylenol by pregnant women and children, claims that decades of scientific research have not supported.
Meanwhile, Kenvue, the maker of Tylenol, rejected the claims. “We believe independent, sound science clearly shows that taking acetaminophen does not cause autism. We strongly disagree with any suggestion otherwise and are deeply concerned with the health risk this poses for expecting mothers,” according to a Reuters report, citing a company statement.
Kenvue, which was spun off from Johnson & Johnson in 2023, saw its shares fall 7.5% during Monday’s session to a record low before recovering 4.4% in extended trading.
In a White House news conference, Trump repeatedly advised women and parents not to use the painkiller, saying, “Don’t take Tylenol. Fight like hell not to take it,” while acknowledging he was not a doctor.
Standing alongside Health Secretary Robert F. Kennedy Jr., a longtime vaccine critic, Trump also called for a reexamination of vaccine schedules, urging separate measles, mumps, and rubella shots, and stating that the hepatitis B vaccine should not be administered until age 12, despite longstanding medical guidance recommending it within 24 hours of birth.
Tylenol is Kenvue’s largest brand, accounting for a mid-to-high single-digit percentage of total sales, The Wall Street Journal noted, citing Morningstar. Trump’s warning also comes as Kenvue continues to face litigation over acetaminophen, with hundreds of lawsuits alleging a link to autism or ADHD currently under appeal after a federal judge last year ruled the scientific evidence unreliable.
Meanwhile, acetaminophen remains an important option for pregnant women, and vaccines have saved millions of lives, with UNICEF estimating at least 154 million lives preserved over the last 50 years.
The Trump administration also announced steps to position leucovorin, a form of folic acid currently used in chemotherapy support, as a treatment for autism-related symptoms.
The FDA approved a version of the drug from GSK and cited a review of 40 patients with cerebral folate deficiency, a rare metabolic disorder linked to neurological symptoms. Medicaid coverage for leucovorin will be extended to autism patients, with expectations that private insurers will follow.
Researchers reiterated that there is no solid evidence that acetaminophen causes autism. A 2024 study using 2.5 million Swedish children found no causal relationship. In 2025, a review of 46 previous studies was done, which found an association, but it does not show cause and effect.
Researchers advised that pregnant women who need acetaminophen should continue taking it at the lowest dose and for the shortest time. Bigger, randomized trials are still needed to determine leucovorin’s potential.
On Stocktwits, retail sentiment for Kenvue was ‘extremely bullish’ amid ‘extremely high’ message volume.
One bullish user said the administration’s comments unfairly singled out Kenvue as if Tylenol were the only acetaminophen brand on the market, adding that people weren’t about to stop using the drug for everyday needs and calling the concerns overblown.
Another user said that they were buying every dip in Kenvue shares and planned to hold through the lawsuits and any eventual settlement.
Kenvue’s stock has declined 18.3% so far in 2025.
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