Leucovorin (brand name Wellcovorin) is is a man-made version of folate (vitamin B9), a vitamin that helps your body make and repair DNA, and produce healthy cells. It’s especially important for the brain and nervous system.
For decades, leucovorin has been used as a "rescue" drug in cancer treatment, protecting healthy cells from chemotherapy's toxic effects. However, a significant shift is underway.
The FDA is now working to expand its use to treat cerebral folate deficiency, a neurological condition that has been linked to autism.
In September 2025, the U.S. Food and Drug Administration (FDA) took action to expand the approved use of leucovorin calcium tablets to include treatment for cerebral folate deficiency (CFD): a condition linked to autism-like symptoms such as:
However, the FDA emphasizes that more research is needed to confirm safety and effectiveness in broader autism populations.
Leucovorin is used in:
Leucovorin is available in several forms:
The form ande dose depend on condition:
Most people tolerate leucovorin well, but it can have side effects. When used alone, side effects are rare and may include:
When used in combination with other chemotherapy agents like 5-fluorouracil, it can increase the toxicity of the other drug, leading to more common and potentially severe side effects such as:
Leucovorin can interact with other medications, which may require dose adjustments or careful monitoring.
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While research shows leucovorin can significantly improve verbal communication for some autistic children—especially those with folate receptor autoantibodies—experts caution that it is not a universal cure and should be used within a comprehensive, physician-guided care plan.
Early clinical evidence is promising, but further large-scale studies are needed to fully clarify which patients benefit most and how best to implement this therapy.