Whilst I have not had AC treatment I am a very fair skinned redhead who avoids the sun so take the vitamin D level recommended by Osteoporosis society - which for me is covered by 2 Caltrate Bone and Muscle Health daily - 1 at breakfast and one late afternoon.Like many others I need it as I had osteoporosis before breast cancer including a fracture - the latter is a major worry as I take Letrozole/Femara which is not good for bone density.I also have 6 monthly Prolia injections to help build bones.My first annual check up is coming up this March and will be interested to see how my bone density and vitamin d levels are.