Solgar Folate 666 mcg DFE (Metafolin 400 mcg)

Our assessment

The evidence shows that Solgar Folate 666 mcg DFE (Metafolin 400 mcg) is a targeted supplement for supporting healthy cell division and red blood cell formation. Because the active ingredient is methylfolate (Metafolin), it is directly usable by your body without needing conversion, which can be beneficial if you have a genetic variation affecting folate metabolism. However, data on the specific safety profile of this product is limited.

How it works

Think of folate as a essential building block for your DNA and new cells. This supplement provides 400 mcg of (6S)-5-methyltetrahydrofolic acid (Metafolin), which is the active form of folate your body can use immediately. For reference, the total 666 mcg DFE (Dietary Folate Equivalent) accounts for the higher bioavailability of this form compared to folic acid. This mechanism supports processes like red blood cell maturation and neural tube development [NIH ODS].

Safety profile

Data not available for this specific product. The FDA has received a total of 592,059 adverse event reports across all supplements, but specific side effect counts for Solgar Folate 666 mcg DFE are not listed in the provided data. When considering calcium, a separate ingredient in the data, high intakes can lead to side effects such as constipation, nausea, and abnormal heart rhythms [NIH ODS]. No side effect data for this product is available from the FDA data provided.

Our recommendation

Start by taking one tablet daily with food. Because folate can mask a vitamin B12 deficiency, have your doctor check your B12 levels before starting supplementation. Choose this product if you need a bioactive form of folate. Always consult your physician before beginning any new supplement, especially if you are pregnant or nursing [NIH ODS].

Supplement labels contain several key sections regulated by the FDA:

• Serving Size — The recommended amount per dose. Always check this — some products require multiple capsules per serving.
• Amount Per Serving — Shows the quantity of each nutrient in the product, typically in IU (International Units), mg (milligrams), or mcg (micrograms).
• % Daily Value (%DV) — Indicates how much a nutrient in a serving contributes to a daily diet. 5% DV or less is low; 20% DV or more is high.
• Other Ingredients — Lists inactive ingredients like fillers, binders, and capsule materials (e.g., gelatin, cellulose, magnesium stearate).
• Suggested Use — The manufacturer's recommended directions for taking the supplement, including timing and dosage.

Source: FDA Dietary Supplement Labeling Guide