On September 22, the US Food and Drug Administration announced it was approving a new use of a drug called leucovorin calcium tablets as a treatment for cerebral folate deficiency, which the administration also presented as a promising treatment for the symptoms of autism. In the days and hours after the announcement, tens of thousands of parents of autistic children joined a Facebook group, first set up in May, to share information about the drug.

The Leucovorin for Autism group was flooded with chaos, confusion, and conspiracy theories, according to a WIRED review, with parents, pediatricians, nurses, and affiliate marketers seeking to fill the void of information left by the Trump administration.

One angry parent shared an email from their health care provider refusing to prescribe leucovorin, even after the FDA announcement. “Get a different doctor,” a group member responded.

Another parent shared a spreadsheet filled with the names of doctors who they claimed would prescribe the drug. Two individuals who claimed to be nurses argued over whether leucovorin should be prescribed at all. Many others shared links to unproven alternatives, including folinic acid supplements that can be ordered online. Some offered advice on what dosage to give, as the FDA has yet to provide such information. Others pushed conspiracy theories, blaming “big pharma” for covering up the effectiveness of leucovorin for years, or blaming vaccines for causing autism.

One person suggested prayer as a way to treat autism: “You may think this is crazy … get him in church. Get him listening to Christian music. Even just Christian kid songs. Children like him are so innocent … they can feel Gods presence and the comfort of the Holy Spirit.”

Many shared their positive experiences with leucovorin, which has for years shown promise as a potential treatment for certain symptoms for some autistic people. “We have noticed a huge difference,” one parent wrote this week about their child, who had been taking leucovorin for two and a half weeks. “Anxiety is decreased, calmness, happiness, listening so well, lots of hugs and love to not only us but friends, and her mouth is really moving and making new sounds even like raspberry sounds which we have never heard.”

But others shared negative reactions to taking the drug. “Did you notice your kid's behavior improving after starting Leucovorin??” one group member wrote on Monday. “My daughter becomes aggravated very easily, hits, & screams to the top of her lungs!”

For decades, the parents of autistic children have been sold false hope by charlatans claiming their products could cure autism. While the Trump administration is not making this claim, it has created confusion by changing leucovorin’s label without rigorous testing as an autism treatment or providing information about dosages or length of treatment. This information void is now being filled by posters on Facebook.

“Families are understandably worried when they hear a single drug being presented as a possible ‘answer’ to autism,” says Danielle Hall, director of health equity initiative at the Autism Society of America. “But autism is not caused by one thing, it’s a complex mix of genetic, biological, and environmental factors. Announcing a ‘cause’ or ‘cure’ without rigorous science not only fuels stigma but also harms families who are left with more confusion than clarity.”

Leucovorin works by boosting the body’s folate levels, which is critical for the healthy production of red blood cells. It has typically been used to treat cancer patients, to counteract the impact of chemotherapy on the body’s immune system. For decades, it has been prescribed off-label by some doctors to treat cerebral folate deficiency, which had been linked to autism by now-sidelined research. However, it has never undergone the sort of expansive clinical trials usually required for drugs approved to treat autism.

The approval was based not on years of rigorous study and clinic trials, as is typical for an FDA drug approval, but instead on a “systematic analysis of literature published between 2009-2024.” The problem with this, experts say, is that there is very little research on the effectiveness of leucovorin for this specific use.

Keith Joyce stumbled across leucovorin last December while trying to find ways to improve the life of his 4-and-a-half-year-old autistic grandson, Jose. He spent the next few months researching the drug and speaking to neurologists. In April, he sent his research to Jose’s developmental behavioral specialist, who agreed to prescribe the drug.

In the five months since he began treatment, Jose has gone from being typically nonverbal to babbling constantly.

“Within days I started seeing a difference,” Joyce tells WIRED. Before taking leucovorin, “he struggled with two-word sentences, and last night, I had a three or four minute conversation about family with him.”

Joyce wanted to share his research with others because there were so few resources online, so he started the Leucovorin for Autism group on Facebook in May.

There was some interest in the group initially, and by August around 8,000 people had joined, Joyce says. But then came the news that the Trump administration and US health secretary Robert F. Kennedy Jr. were going to be recommending leucovorin as a possible treatment for autism—the group exploded. In the week following Makary’s announcement, membership of Joyce’s group jumped to almost 60,000 people.

Even before the official announcement was made, tens of thousands of new members had joined based on speculation about the drug.

Then, last month, President Donald Trump pushed baseless allegations that the active ingredient in Tylenol and vaccines may contribute to an autism diagnosis. FDA head Marty Makary announced on September 22 that the agency was approving the use of leucovorin to treat folate deficiency in the brain, a deficiency some people with autism symptoms have.

“Leucovorin is something that has for many years been prescribed off-label for autistic people generally, with inconsistent findings,” says Matthew Lerner, program leader of the Life Course Outcomes research program at the AJ Drexel Autism Institute at Drexel University. “There's been some small research studies on it to date, also with pretty inconsistent findings. But honestly, we don't know a lot about it, even from those studies, in terms of what would be an optimal dosage, what would be an optimal time period to be on it.”

The FDA did not respond to a request for comment.

While some members urged Joyce to make the group private, he wanted to keep it public to allow as many people as possible to find the information he had posted on the group. But allowing everyone to join a Facebook group brings a lot of problems, including what Joyce has labeled as “the haters.”

“I’ve spent most of the day today going through my filters and deleting and banning people because they want to shame people, saying you shouldn't give them vaccines or you shouldn't have done this, you shouldn't have done that,” Joyce says. “Anybody who wants to talk about what caused autism, they can go somewhere else.”

The Department of Health and Human Services, of which the FDA is a constituent agency, has clarified since the announcement that it is only recommending the use of prescribed leucovorin taken in consultation with a doctor, and not alternatives such as folinic acid, an over-the-counter supplement.

Within the Facebook group, however, a lot of parents are recommending alternatives to those who can’t get leucorovin, including folinic acid and other supplements, something Joyce says is very concerning.

“People are going to these supplements, which really scares me, because now you're doing it without a doctor,” says Joyce, adding that people don’t know what is in the supplements or what dosage they should be giving.

There also appear to be people in the group seeking to profit from the uptick in interest in leucovorin—which is a cheap generic drug.

“There's a couple of [supplement makers] out there spamming this group really bad,” says Joyce. “I don't know if they're affiliates from a website or whatever, but we're constantly removing their little ads.”

Among the worst offenders, he adds, is a supplement company called Spectrum Awakening, which last year breached advertising standards in the UK after it claimed in a Facebook ad that one of its supplements could treat language issues. The company did not respond to the regulator before its ruling.

Joyce claims that his group had also been spammed with links to iHerb, another supplement company where Mehmet Oz, the current administrator of the Center for Medicare and Medicaid Services, was formerly a pitchman and investor. iHerb’s folinic acid is currently listed on the website as out of stock until late in November.

Spectrum Awakening and iHerb did not respond to requests for comment. iHerb told Newsweek it is no longer working with Oz or with the Trump administration. The Department of Health and Human Services did not respond to a request for comment.

Hall, the director of health equity initiative at the Autism Society of America, says the group and its dozens of affiliates across the country have also been inundated with calls from concerned parents who are seeking more information after the FDA’s announcement.

“Last month's press conference was a prime example of how misinformation doesn’t just confuse, it erodes trust in science, doctors, and public health,” says Hall. “Autism has a painful history of mother-blaming myths like the ‘refrigerator mother’ theory. Today we’re seeing that cycle repeat with pregnancy-related claims, which re-traumatize families and shift focus away from real solutions. False claims waste resources and keep us from making true progress.”