It’s a dose of disappointment.

A supportive care drug that may help ease hyperactivity and improve speech and communication in children with autism has become so popular that desperate parents may have trouble getting their hands on it.

Leucovorin — a reduced form of folate or vitamin B9, an essential nutrient our bodies can’t make on their own — took center stage last fall when the White House touted it as an “amazing” treatment for autism.

A study published Monday in JAMA Network Open found that leucovorin prescriptions increased by more than 2,000% over three years.

Prescriptions remained relatively stable until early 2025, upon publication of a widely viewed news story about a family who reported dramatic language improvements in their child after treatment.

Interest in leucovorin, a cheap drug used to protect healthy cells from chemotherapy, further spiked when the Trump administration promoted it in September 2025.

By November 2025, rates climbed to over 835 prescriptions per 100,000 outpatient hospital encounters, more than double the amount only a few months prior.

“What this study shows is how quickly information shared through news coverage, social media and public figures can influence real-world prescribing patterns,” study author Dr. Joshua Rothman said in a statement.

“Even before large clinical trials establish whether a treatment is truly safe and effective for broad use,” he added.

A 2012 clinical trial found that about one-third of young participants with autism who took leucovorin twice daily showed significant improvements in speech and language.

Side effects like hyperactivity resolved quickly, and no serious adverse events were reported.

Low folate in the brain — a condition known as cerebral folate deficiency — is highly prevalent in kids with neurodevelopmental disorders, especially autism, which affects about one in 31 US children.

As leucovorin popularity has skyrocketed, doctors have struggled to meet demand.

“I can’t even tell you how much of an influx we’ve had,” Dr. Richard Frye, a pediatric neurologist who studies the medication, previously told The Post. “We can’t schedule any more patients until 2028.”

With the drug hard to come by, parents are swapping in over-the-counter folic acid, a move that Frye warned “may do more harm than good.”

While leucovorin and folic acid are both forms of B9, there is a crucial difference. Folic acid is synthetic and must be converted first, while leucovorin is an active form that the body can use immediately.

The body can activate about 400 micrograms of folic acid a day, but leucovorin doses are in milligrams — far higher than standard folic acid supplements.

Too much folic acid can overwhelm the body’s conversion process, leaving unmetabolized folic acid in the blood.

Studies suggest this could even increase the risk of autism in children of pregnant women, according to Frye.

“Folic acid is good to a point, like in your everyday regular supplement,” Frye stressed. “But if you need higher doses of folate because of a folate deficiency or other metabolic issues, you can’t use folic acid.”

While leucovorin was approved by the FDA for cerebral folate deficiency in March, it is not approved for autism spectrum disorder.