I started on Vit D before chemo as my levels were low (27) and still take it 5 years later. I burn easily so stay out of the sun which does not help your Vit D levels ( if I get a skin cancer, I will spit!). I take Vit B for peripheral neuropathy, think it stil helps but that's a slow burner. Magnesium and Q10 at cardiologist's suggestion. Biotin to help strengthen hair (had a slight shedding scare 2 years after fully regrown but all fine). Fish oil, calcium and probiotic. I am on letrozole, have no aches or joint pains, just the ageing knees I had before all this started!