I have Hashimoto's and stayed away from Iodine for a long time because of it. However, meds were not doing enough for me so I started to supplement Iodine almost 4 months ago. I jumped in both feet first with 50 mg then quickly to 100 mg. I experienced a lot of ups and downs during the first three weeks and then I became very hyperthyroid for a week or two and after that the hyperthyroid settled down but I started feeling very hypo. At first I thought it was just detox but lately I have been supplementing with smaller amounts 6 mg and started to feel my metabolism speeding up again almost too much. I'm not sure what a perfect dose will be for me but I can say that I think the 50 mg I was taking after awhile was having a suppressive effect on my thyroid and that I don't need that much long term. However, I do think that the 50-100 mg was necessary in the beginning to knock the receptors clear of the halides. I think it was when I went hyper that the Iodine was actually starting to be utilized in a meaningful way. I guess it just shows that everyone is unique. Hashimoto's is complicated, I believe Brownstein's book Iodine why you need it: why you can't live without it is excellent in it's exploration of potential causes ie. infectious, coagulation disorders, allergies etc. The iodine doctors strongly believe that iodine is the treatment for Hashimoto's. I have not had my antibodies tested yet so I don't know how the iodine is affecting them but I do know for example that avoiding gluten positively impacted my antibodies. There is lots of info here if you search Hashimotos or autoimmune so that your friend can make an informed choice. My thought is it's worth a try especially if nothing else is working. I would continue to monitor antibodies though and plan to do this for myself.