As a chemo patient with TEC, this is very welcome news!!! One thing to consider: in high enough doses, vitamin D can be toxic as it’s fat-soluble and excess doses are not excreted by the kidneys. This is definitely something to check with your doctor about and have a vitamin D level drawn before starting and after a few weeks of high doses. I will definitely be emailing my medical team asking about this...TEC and HFS are miserable. :(. Thanks for the info!