Choose Vitamin D3 for best absorption

Vitamin D3 is the most effective and bioavailable form for supplementation, recommended over D2. Dietitians advise choosing D3, ideally with K2 or magnesium, in an oil-based capsule or liquid form for optimal absorption. Dosage should be determined by blood tests, as excess vitamin D can be harmful. Look for third-party certifications like NSF or USP to ensure supplement purity and potency, as the industry is largely unregulated.