The scientific community is pushing back after U.S. President Trump identified the widely used pain reliever Tylenol (generic name: acetaminophen) as a cause of autism. At a White House press conference on the 22nd (local time), President Trump advised pregnant women to avoid the drug, stating, “Tylenol use during pregnancy could be a major factor in the development of autism.” Experts point out that the claim lacks scientific evidence, as large-scale studies have not established such a link.
According to the international journal ‘Nature’ on the 23rd, a research team from Sweden's Karolinska Institute published a study in 'JAMA Psychiatry' in 2023. The study, which tracked more than 2.5 million births, concluded that the association between acetaminophen use during pregnancy and the development of autism was “very minimal or nonexistent.”
A comparison based on children's autism diagnoses showed a negligible difference: the rate of autism in the Tylenol-exposed group was about 1.42%, compared to 1.33% in the unexposed group. Furthermore, an analysis comparing siblings from the same mother where only one was exposed to Tylenol did not show a clear increase in autism risk. Another study conducted in Japan reported similar findings.
Experts explain that women who take pain relievers during pregnancy often have underlying conditions such as infections or inflammation, and these health factors could potentially influence the risk of developing autism.
Some critics also point out that the research relies on mothers' self-reporting, which could introduce memory errors or reporting bias. Additionally, while smaller studies have suggested a link between drug exposure and autism, critics argue that more sophisticated study designs, such as large-scale analyses involving millions of people or sibling comparisons, have not shown any clinically significant differences.
Despite this, the Trump administration has announced it will push for an autism warning label on Tylenol, increasing confusion among pregnant women. Tension is growing throughout the industry. Tylenol's manufacturer, Kenvue, strongly refuted the claim, stating, “Independent and sound studies do not support a causal relationship between acetaminophen and autism.” Kenvue is a consumer health company spun off from Johnson & Johnson. Tylenol is a key product, generating annual sales of about $1 billion (approximately 1.3937 trillion won).
● Leucovorin: From Cancer Adjuvant to Potential Autism Treatment
Adding to the controversy is a new potential therapeutic drug introduced at the same event. The White House mentioned ‘Leucovorin’ (generic name: folinic acid calcium) as a drug with potential for treating autism. Folinic acid calcium, marketed by GlaxoSmithKline (GSK), was originally used to reduce the toxicity of the anticancer drug 'methotrexate' or to enhance the effects of the anticancer drug 'fluorouracil (5-FU)'.
It has recently emerged as an ‘autism treatment candidate’ following studies showing that when administered to some children with a blocked pathway for transporting folate to the brain, their language and communication skills improved.
Methotrexate is a drug that inhibits the proliferation of cancer or immune cells in diseases like leukemia and rheumatoid arthritis. It can also be highly toxic to normal cells. When Leucovorin is administered alongside it, it supplements the impaired folate metabolism, thereby protecting normal cells.
5-FU works by interfering with DNA synthesis to stop cancer cell proliferation. Using Leucovorin with it enhances its anticancer effect by more strongly inhibiting the enzyme that 5-FU binds to. For this reason, it is an essential part of standard chemotherapy regimens for colorectal cancer.
The U.S. Food and Drug Administration (FDA) had previously announced it would expand the indication for Leucovorin as a treatment for cerebral folate deficiency (CFD) and pursue a label change. CFD is a condition where a lack of folate in the cerebrospinal fluid leads to language delays, seizures, and cognitive impairment, and it is also reported in some children with autism.
In a clinical trial, 40 children who took Leucovorin showed significant improvements in language and communication skills compared to a placebo control group. After a comprehensive review of studies published between 2009 and 2024, the FDA concluded that Leucovorin could provide substantial help in improving symptoms.
Experts also added a note of caution. They point out that the effects of Leucovorin were seen only in some children, and there is a lack of large-scale clinical trials and long-term data. Alycia Halladay, Chief Science Officer of the U.S. Autism Science Foundation (ASF), told local media, “Leucovorin should not be seen as a cure for autism,” and added, “Large-scale research is needed to determine who might benefit and under what conditions.”
