Folinic Acid
Also called 5-Formyl-THF / Leucovorin
Folinic acid (5-formyl-tetrahydrofolate) is a naturally occurring, active form of folate that does not require the MTHFR enzyme to become usable in most downstream pathways. Unlike L-Methylfolate, it does not directly donate a methyl group, making it far less likely to trigger over-methylation reactions. This makes folinic acid an excellent alternative for people with MTHFR variants who are sensitive to methylfolate, and it is commonly used in clinical settings for children with autism spectrum disorder and nutrient protocol stacks. It still provides folate to the pathways that matter for DNA synthesis and cell division.
Best for
MTHFR variants who react poorly to L-Methylfolate, children
Absorption
High
Tolerability
Excellent; rarely causes over-methylation
Typical timing
With or without food; morning is common to support daytime methylation
How to take Folinic Acid
A typical dose of Folate (B9): 400–1,000 mcg DFE per day; up to 1,000 mcg L-Methylfolate for MTHFR. Best timing: With or without food; morning is common to support daytime methylation. The form you choose mainly affects absorption and how easily it sits with your stomach, not the overall dose.