Vitamin B9, also known as folic acid or folate, is a water-soluble vitamin that is essential for many important functions in the body, including the production of red blood cells, DNA synthesis, and nervous system function. Folinic acid, also known as 5-formyl tetrahydrofolate, is a form of vitamin B9 that is often used in dietary supplements and fortified foods.

Folinic acid is found naturally in many foods, including leafy green vegetables, citrus fruits, beans, and whole grains. It can also be synthesized in the body from dietary folate. Alternative names for folinic acid include 5-formyl tetrahydrofolate, leucovorin, and citrovorum factor.

Folinic acid is a stable and bioavailable form of vitamin B9 that is often used in dietary supplements and as a medical treatment for certain conditions, including methotrexate toxicity, anemia, and certain types of cancer. It has been shown to be effective in increasing the levels of active folate in the body, which can improve overall health and reduce the risk of certain diseases.

Studies have shown that folinic acid may be beneficial in preventing birth defects, such as neural tube defects, when taken by pregnant women. It has also been shown to be effective in improving cognitive function in people with dementia and reducing the risk of certain types of cancer, including colorectal cancer. Additionally, folinic acid may be helpful in treating depression, improving cardiovascular health, and reducing the risk of age-related macular degeneration.

The recommended daily intake of folinic acid varies depending on age, gender, and health status. In general, adults are recommended to consume at least 400 micrograms of folate per day, which can be obtained through a balanced diet or supplementation. Pregnant women are recommended to consume at least 600 micrograms of folate per day to reduce the risk of birth defects. However, the appropriate dosage of folinic acid for specific medical conditions should be determined by a healthcare professional.