Doctor's Best Fully Active Folate 400 With Quatrefolic 400 mcg

Our assessment

The evidence shows that Doctor's Best Fully Active Folate 400 With Quatrefolic provides 400 mcg of folate, a B vitamin essential for DNA synthesis and cell division. However, you should know that the primary ingredient in this product is folate, not calcium. The data provided on calcium indicates that while calcium supports bone mineralization and neuromuscular relaxation, high intakes might increase the risk of heart disease and prostate cancer [NIH ODS].

How it works

This product delivers folate in its active form (Quatrefolic), which your body can use immediately without needing to convert it. Think of folate as a cellular builder — it helps your body produce red blood cells and supports proper nerve function. For calcium, which is not the main ingredient here, the mechanism involves bone mineralization and neuromuscular relaxation [NIH ODS].

Safety profile

Data not available for specific folate adverse events from the FDA data provided. The FDA received a total of 592,059 adverse event reports across all supplements, but specific report counts for this product are not listed. For calcium, high blood levels can cause poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS].

Our recommendation

For folate supplementation, 400 mcg daily is a standard dose that meets the general RDA for most adults. If you are taking calcium supplements separately, be aware that calcium can reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS]. Always take calcium at a different time from these medications. Start with the recommended dose and consult your healthcare provider if you have concerns about interactions or your specific health needs.

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