For people with MTHFR gene variations, supplementing with the already activated form of folate (5-MTHF/5- METHYLTETRAHYDROFOLATE/LEVOMEFOLIC ACID) is far more effective in providing this form of folate than introducing the pre-converted form to the body through typical folate supplements. L-Methylfolate (5-MTHF) supplements provide the active form of folate naturally present in the body and available for biological action. 5-MTHF—the “active” form of folate that is able to pass the blood brain barrier. However, without a properly functioning methylenetetrahydrofolate reductase, MTHFR this conversion cannot take place and folate is not converted to forms that can cross the blood brain barrier. That is where 5-MTHF supplements come in. Levomefolate calcium is structurally identical to L-5-methyltetrahydrofolate (L-5-methyl-THF), a metabolite of vitamin B9. Mean baseline concentrations of about 15 nmol/L are reached in populations without folate food fortification under normal nutritional conditions. Orally administered levomefolate calcium is absorbed and is incorporated into the body folate pool. Peak plasma concentrations of about 50 nmol/L above baseline are reached within 0.5 – 1.5 hours after single oral administration of 0.451 mg levomefolate calcium. Steady state conditions for total folate in plasma after intake of 0.451 mg levomefolate calcium. In red blood cells, achievement of steady state is delayed due to the long lifespan of red blood cells of about 120 days. Levomefolate calcium is a part of contraceptive tablets: SAFYRA. Safyral is an estrogen/progestin COC (Combined Oral Contraceptive) containing a folate, indicated for use by women to: prevent pregnancy and raise folate levels in women who choose to use an oral contraceptive for contraception. COCs lower the risk of becoming pregnant primarily by suppressing ovulation. Other possible mechanisms may include cervical mucus changes that inhibit sperm penetration and endometrial changes that reduce the likelihood of implantation.

Methylenetetrahydrofolate reductase (MTHFR) is an enzyme required for the formation of 5-methyltetrahydrofolate (5-MTHF), a form of folate able to cross the blood-brain barrier and which is necessary as a substrate for the remethylation of homocysteine to methionine by methionine synthase. Patients with severe MTHFR deficiency cannot make 5-MTHF and have extremely low levels in the CSF. Only treatment with oral 5-MTHF given as calcium mefolinate resulted in an increase in CSF 5-MTHF.