What is the best time for sun-exposure in patient with vitamin d deficiency?

Supplements are best: Though sun exposure will potentially help the body create vitamin D, the newest research suggests that sunlight is inadequate for vitamin D synthesis in most regions of the world and for people of darker complexions this is an even greater problem. With modern vitamin D supplements, there really is no reason to rely on sunlight alone to get vitamin D levels up. Skin cancer risk is another reason.