D3 supplementation, oil filled capsules. 5k IU per day should be fairly safe for most people, at least for a few months. Read up on it first and make sure you know what you are doing - doing it properly over a period of time requires testing, and after a while the average person shoudnt supplement calcium anymore because they become much more efficient at absorbing it from food.

Be aware that there are many things out there that work, and even more that dont. Doctors wont/cant talk about the ones that do because if they aren't FDA approved to treat a condition then mentioning something like D3 puts the malpractice insurance and/or license at risk.

Good luck.