If President Donald Trump wanted Americans to take away one message about autism, it was this: Blame Tylenol. During his September press conference on the subject, Trump warned pregnant women more than a dozen times not to take the drug, even though two massive studies had found no meaningful association with the disorder in children. He also spread false rumors that “essentially no autism” can be found in Cuba or among the Amish. The other stated purpose of the event—the announcement of what FDA Commissioner Marty Makary called an “exciting treatment” for autism—was largely overshadowed by the president’s performance.
But parents of autistic children took note of that promised remedy. How could they not? Officials suggested that the little-known drug, leucovorin, could alleviate the symptoms of profound autism, perhaps allowing children with speech difficulties to find their words. Hundreds of thousands would benefit, according to Makary. No, it wasn’t a cure—officials stopped short of invoking that word—but it sounded like a miracle.
After the government’s endorsement, many parents rushed to get their hands on leucovorin. They soon discovered that they were effectively taking part in a nationwide experiment with few guidelines—assuming, that is, they could even get a prescription.
The theory behind treating autism with leucovorin is that the drug gives autistic kids something they’re missing. Children with autism seem to be more likely than other children to produce an antibody that prevents folate, also known as vitamin B9, from reaching their brain. Because folate plays a role in brain development, some researchers—most notable among them Richard Frye, a doctor who has been prescribing and promoting leucovorin for nearly two decades, and who told me he spoke with leaders in the Health and Human Services Department before the press conference—think these antibodies might hamper the growth of a child’s language abilities. Leucovorin is essentially a massive dose of folate, delivered in a form that can bypass those antibodies.
But that theory, which has long been debated in autism subreddits and Facebook groups, hasn’t gained traction among mainstream autism scientists. They point to a 2018 study that found that autistic children and their non-autistic siblings were equally likely to have these antibodies. The clinical evidence for leucovorin’s effectiveness for autistic kids is limited to a handful of small studies that don’t measure the same outcomes. No large, randomized, placebo-controlled trial has ever been conducted. If you want to get the drug for autism, it has to be prescribed off-label, which many doctors refuse to do.
Part of the Trump administration’s promise was to make leucovorin more accessible to patients and easier for doctors to prescribe. So far, nothing official has happened. At the press conference, Makary promised that the FDA would change leucovorin’s label so that doctors could start prescribing it to kids with autism. But when the FDA formally laid out its leucovorin plan two days later, it made no mention of autism. The plan instead centered on cerebral folate deficiency, an extremely rare genetic condition. Emily Hilliard, an HHS spokesperson, wrote in an email that “the FDA’s current action is focused specifically on cerebral folate deficiency,” noting that some of its symptoms overlap with autism. (My other questions about the administration’s leucovorin rollout went unanswered.) A spokesperson for GSK, which originally manufactured the drug and controls the label, told me that the company submitted an application for the label change this week.
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During the press conference, Robert F. Kennedy Jr., the secretary of health and human services, said that HHS would “help doctors treat children appropriately” with leucovorin. But Alycia Halladay, the chief science officer at the Autism Science Foundation, told me that physicians she’s spoken with have heard nothing from HHS. For her part, Halladay doesn’t believe that enough evidence exists to recommend leucovorin as an autism treatment. The American Academy of Pediatrics has also said that the current data are lacking. In a statement, the organization allowed that if physicians prescribe the medication, they should work with families to monitor side effects; some parents report increased hyperactivity and aggression after their kids take leucovorin.
Several researchers I spoke with compared the excitement about leucovorin to the enthusiasm for secretin, another drug that was popular as an autism treatment in the 1990s after early promising results. More rigorous clinical trials later showed that it wasn’t effective. Halladay said she’s heard from multiple doctors, including her child’s pediatrician, that they’ve been besieged with calls from parents hoping to get a prescription. One doctor in Chicago told me he had received dozens of inquiries.
In the absence of official advice on leucovorin, parents—almost always moms—of kids with profound autism have been turning to one another for opinions and encouragement online.
Some post regular updates on TikTok and Instagram detailing their kid’s progress on leucovorin, saying they’ve noticed more regular eye contact, fewer repetitive movements and sounds, or improvements in language use. In the comments, fellow parents complain about not being able to get the drug (“My sons pediatrician refuses, wants us to just wait for prescribing guidelines”), ask questions about dosage (“I just gave her 15 mg today is that too much??”), and wonder whether it’s really working (“how do we know we see results, what do we see?”). Others say their child’s behavior didn’t improve—or even grew worse—after taking the medication (“I didn’t see it helping my son more with speech like we hoped”).
Some insist the drug must be paired with vitamin B12, omega-3, or a certain amino acid; others caution that dairy can reduce its effectiveness. Many want to know about an antibody test that purports to indicate whether a child’s brain is receiving enough folate. But that test isn’t widely accepted as valid, and not all doctors are willing to give it.
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Jessie Carrasco is one of those TikTok moms. She lives with her husband and their three children on the outskirts of the east-Texas city of Tyler. Their oldest son, Ezra, is 11 and has autism. He didn’t talk until he was 4; she credits fish-oil supplements, in part, with helping him speak in short sentences and respond to simple questions. (Some studies suggest that omega-3 fatty acids, found in fish oil, may improve communication in autistic children, though the evidence is mixed.) When Carrasco invited me into their backyard, which was lively with chickens and dogs, Ezra ran up, gave me a quick once-over, and then darted off to play on the swing set with his younger brother.
Carrasco learned about leucovorin after hearing Trump refer to a new treatment for autism during his speech at Charlie Kirk’s memorial service. She emailed Ezra’s nurse practitioner, who was willing to prescribe it but didn’t know enough about the drug to offer advice on how much to give Ezra or how to deal with potential side effects. Since then, Carrasco has posted more than 200 videos on TikTok, most of them documenting Ezra’s progress on leucovorin. One clip shows him serving himself food from a pot on the stove—the first time he’d ever done that, she told me. Her video of Ezra before and after taking the drug has nearly 6,000 likes.
“Since we’ve been giving leucovorin, I think everything that we’ve been trying to teach, he’s started to get it more and faster,” she said. Ezra’s behavioral analyst, Margaret Hawkins, told me that before leucovorin, she used to work with Ezra on pronouncing single words; now she’s coaching him on telling three- or four-sentence stories.
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Without Kennedy and Trump, Carrasco might not have learned about leucovorin; she’s grateful to them for giving her more faith in Ezra’s future, and hopes that the progress she’s seen so far won’t turn out to be a mirage. At the same time, she’s frustrated by the lack of information about how to use the drug and the difficulty she and other parents have had getting their hands on it. “I feel like they presented something and then just kind of left it in the dust,” she said. The last time she checked, the pharmacies in Tyler were out of leucovorin; she was planning to drive to a neighboring town to get more. “I got my hopes up and now I’m nervous,” she texted me recently. “I don’t wanna watch him regress.”
If the posts and comments are any indication, even parents who have managed to get prescriptions, like Carrasco, have been having trouble filling them. Whether the drug is in shortage now is unclear, but it has a history of supply problems going back more than a decade. A drug-shortage database maintained by a pharmacists’ association recently listed leucovorin shortages at five companies. (One of them, Teva, said its 25-milligram pills were in stock, but not its 5-milligram dose; the others either didn’t respond to me or couldn’t confirm whether they had supply issues.)
Perhaps because of shortages—or difficulties finding a doctor willing to prescribe leucovorin at all—some parents are turning to supplemental forms of folate. Such supplements are far less potent than leucovorin, but are usually cheaper and don’t require a prescription. (Even if leucovorin does turn out to be an effective autism treatment, it’s unknown whether low-dose supplements would have any effect.)
Offline, parents have been calling Frye, the longtime leucovorin doctor, who believes that as many as 1 million kids could benefit from the drug. He mostly treats children with significant language delays, though he says that the drug can sometimes help higher-functioning kids too. Frye was the lead author of a small 2016 study that found that children with autism who received leucovorin showed improvements in verbal communication, compared with those given a placebo; he also recently published a book called The Folate Fix. Ever since the press conference, his office has been inundated with calls and emails from parents who want the drug for their children.
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For years, Frye has had a backlog of patients wanting to see him, but the White House announcement, he told me, made an “impossible situation worse.” He already has about 1,000 patients who are taking leucovorin, and he isn’t planning to accept any new ones until 2028. According to Frye, the FDA has asked him to submit an application to conduct clinical trials on leucovorin as an autism treatment, but last week, he told me that “not much is going on at this time.” He guesses those trials will take about two years. In the meantime, parents will be left to experiment with leucovorin on their own.
