Calculate your personalized vitamin D needs based on age, sun exposure, skin tone, and geographic location.
Higher latitudes >40° get less vitamin D from sun
The RDA is 400 IU for infants, 600 IU for ages 1-70, and 800 IU for adults over 70. However, many experts suggest 1000-2000 IU daily may be optimal, especially for those with limited sun exposure.
It depends on your location, skin tone, and lifestyle. People living above 40° latitude, those with darker skin, or those who spend most time indoors often need supplementation, especially in winter months.
Excessive vitamin D (>4000 IU daily long-term) can cause hypercalcemia, kidney stones, and organ damage. Always consult a healthcare provider before taking high-dose supplements or if you have kidney/heart conditions.