A clinical trial that supported the use of leucovorin (Wellcovorin) for the treatment of autism spectrum disorder was retracted by the publisher. The US FDA touted leucovorin to treat autism, despite the lack of strong clinical evidence that it was safe and effective for this use.

As with the current push by HHS Secretary Robert F Kennedy Jr to claim that vaccines cause autism, they want parents to believe that there is a simple treatment for autism. Vaccines do not cause autism, and the causes are mostly genetic. That means there are probably no drugs that are going to “cure” autism.

Parents of autistic children search the world over for “cures,” mostly heading to quack treatments that have never been shown to do anything. I guess that’s why leucovorin seemed so promising: it appeared to be a real drug, supported by clinical trials, though those trials were unconvincing.

Let’s take a look at what happened to this “clinical trial.” Spoiler alert — more garbage “science” in the world of autism.

What is leucovorin?

Leucovorin, also known as folinic acid, is a form of folate used primarily to treat or prevent conditions related to folate deficiency. It is commonly used as an antidote to reduce the harmful effects of the chemotherapeutic drug methotrexate, especially in high doses, and to treat certain types of anemia caused by a lack of natural folic acid in the body. Additionally, leucovorin is utilized in combination with other medications, such as 5-fluorouracil, to enhance the effectiveness of cancer treatments.

The FDA announced that it had “initiated the approval” of leucovorin for cerebral folate transport deficiency (CFD), a rare condition that involves impaired folate transport into the brain. Children with this condition can display autistic features.

Cerebral folate transport deficiency is caused by a low level of 5-methyltetrahydrofolate (5-MTHF) in cerebrospinal fluid (CSF) due to a disruption in the function of the folate receptor alpha. It is diagnosed by determining 5-MTHF levels in the CSF. While some people with autism show high levels of folate antibodies, so do their non-autistic family members.

According to a notice in the Federal Register, the FDA said it reviewed data from more than 40 patients with genetically confirmed CFD, which showed that the drug could normalize folate levels in these patients’ CSF.

Just to be clear, the FDA has just approved this drug for a very rare and very specific condition, CFD, not autism generally.

Evidence supporting its use in autism is limited: only a handful of trials have tested leucovorin in people with autism, and most have very small sample sizes.

Leucovorin clinical trial for autism retraction

The original paper, by Indar Kumar Sharawat, MD, pediatric neurologist, All India Institute of Medical Sciences, Rishikesh, India, and colleagues, was published in the European Journal of Pediatrics on 7 September 2024. The paper was retracted on 29 January 2026.

The original study, a randomized, double-blind, placebo-controlled trial, tested oral leucovorin in 77 children with autism spectrum disorder (ASD). The trial reported a significant improvement in Childhood Autism Rating Scale scores in the leucovorin group compared with the placebo group at 24 weeks.

After numerous errors were pointed out to the publisher, the journal editors decided to retract the article.

The retraction note said:

Following publication, a number of concerns were raised about the data reported in this study directly to the publisher and via PubPeer, in particular that there appear to be errors in the results reported in tables 2 and 3 and concerns with the statistical analyses performed.

Post publication statistical review confirmed several of the concerns raised with the data and statistical analysis and was unable to replicate the results reported in the article from the dataset provided. The Editor therefore no longer has confidence in the validity of the results and conclusions reported in this article.

The American Academy of Pediatrics stated that it does not recommend the routine use of leucovorin for autistic children. The Coalition of Autism Scientists also reviewed leucovorin studies and concluded there was little scientific evidence establishing the drug as a safe and effective autism treatment.

Summary

As I wrote before, the evidence for leucovorin as a treatment for autism was weak and unconvincing. Other scientists are saying the same thing.

This retracted study was the basis for a lot of claims about leucovorin, and now it’s gone. This probably won’t mean anything to people who believe that there must be a simple treatment for autism. They want to believe that leucovorin is the holy grail.

The evidence is just not there.

Citations

• Panda PK, Sharawat IK, Saha S, Gupta D, Palayullakandi A, Meena K. Efficacy of oral folinic acid supplementation in children with autism spectrum disorder: a randomized double-blind, placebo-controlled trial. Eur J Pediatr. 2024 Nov;183(11):4827-4835. doi: 10.1007/s00431-024-05762-6. Epub 2024 Sep 7. Retraction in: Eur J Pediatr. 2026 Jan 29;185(2):109. doi: 10.1007/s00431-026-06769-x. PMID: 39243316.
• Panda PK, Sharawat IK, Saha S, Gupta D, Palayullakandi A, Meena K. Retraction Note: Efficacy of oral folinic acid supplementation in children with autism spectrum disorder: a randomized double-blind, placebo-controlled trial. Eur J Pediatr. 2026 Jan 29;185(2):109. doi: 10.1007/s00431-026-06769-x. PMID: 41606385.

Help the Skeptical Raptor keep writing about autism

There are four ways you can help contribute to keeping this website running at full speed:

1. GoFundMe.
2. Subscribing via Patreon.
3. Buying your favorite stuff on Amazon.
4. Sharing this article on Social Media.