You can get it over the counter at a pharmacy, but it is recommended to consult a doctor before you take it. A doctor can make sure it’s right for you before you take it. It’s usually the first line of treatment when vitamin D levels of people are quite low but a doctor can guide you on which dosage is best for you based on your vitamin D levels. Having vitamin D levels that are too high can be bad for your health too, so it needs to be monitored.