Not only did prescription Vit D do nothing for me...including ever raising my Vit D level, not even one point! Prescription vitamin d is usually in the form of Vitamin D2 and vitamin d2 has many disadvantages and is supposedly an inferior to 'over the counter' vitamin d3 that you can get at a health food store.
After a few years of using it with zero results while eating an almost vegetarian low fat diet, I gave up and stopped taking the rx.
Then later I came to low carb and Paleo, which removes all processed seed oils from diet. So was Eating coconut oil, olive oil and butter and taking 5,000 Vit D3 from the store, 10k in winter. Next spring noticed my skin did not sunburn, measured Vitamin D levels then and ever since have finally been in my goal of 50-80 range year round.No difference In weight loss that I ever noticed but dozens of other good benefits, including possible prevention of a cancer recurrence, why my doctor wants that range.