How To Get Enough Vitamin DThere are 3 ways for adults to ensure adequate levels of vitamin D regularly receive midday sun exposure in the late spring, summer and early fall exposing as much of the skin as possible for 20â??30 minutes being careful to never burn Those with dark skin will need longer exposure time up to six times longer regularly use a sun bed avoiding sunburn during the colder months take 5,000 IU per day for 2â??3 months,= then obtain a 25 hydroxyvitamin D test Adjust your dosage so that blood levels are between 50â??80 ng per mL or 125â??200 nM/L year-round Show Less >>