The connection between MTHFR gene mutations and blood clot risk often centers on homocysteine levels. The common story goes like this: if you have an MTHFR mutation, your homocysteine will be high, and that means you face a greater risk of blood clots. But this narrative oversimplifies a complex relationship.

When you receive blood test results showing high folate levels, it might seem positive at first. However, it can signal a potential issue with MTHFR (methylenetetrahydrofolate reductase) function and highlight risks related to unmetabolized folic acid (UMFA) buildup in the bloodstream.

L-5MTHF is the active form of folate, but ironically, it is far less studied than the synthetic (inactive) form folic acid. Because of that, the safe upper limit of L-5MTHF is not known precisely, but we can draw some conclusions from existing data about the risks of high-dose folic acid.

Blood tests for folate have one big fatal flaw, making them both innaccurate and functionally useless, and the most common folate levels that we see on the blood tests of people with MTHFR might surprise you.