The amounts of vitamin D needed for repair is staggering and then, there's three types, one type will make you ill. Sunlight is the best route to adequately get the right amounts. I have vested interest in vitamin d knowledge...they say can help repair damaged myelin sheath, of which I have damaged sheath.
Yes, it would have to be daily waking up early. Which I do. Too tired by the end of day, to reach for a sleeping pill...