I have hashi. I've gone 2 aprox 2 months on 30mg and then down to 18-24. I started high but had magnesium and - really important - selenium in place - before adding iodine. It's vital to start the selenium a month or so before iodine if you're not supplementing selenium already. (Some papers point to too little selenium as a source to the adverse effects on iodine supplementation reported by some since selenium is required in the transport and usage of iodine.)
My reaction to supplementation:
I've had pretty stable and good temperature also before supplementation (tiny dosage t4 + 2 grains dessicated thyroid in the form of canadian Erfa), but got a small surge of energy and the warmth subjectively I feel + an increased craving for salt. (Not surprising since I normally use too little salt.)
As to my labs:
No changes in t3 or t4. No noticable change in antibodies (but my lab are lousy on antibodies, their measurements are not dependable) and a slight rise in TSH. But a rise in TSH is anticipated by Dr. Brownstein as this signifies that the thyroid is drawing the iodine from the blood... (Here the salt + the selenium is vital)
So for me the scares of iodine supplementation are proven wrong. I even got a much needed surge in hair growth at the time…
But... be sure to monitor your symptoms and your labs. Don't pay too much attention to TSH, but look for overall changes in symptoms and for changes in t3/t4 + antibodies. If you look back there is a slideshow with Dr. Brownstein somewhere that explains the need for salt + selenium in order to keep the antibodies down for hashi's patients while on iodine.
Female, have Hashimotos w/lots of antibodies treated with Erfa + levaxin (Norwegian equivalent to synthyroid)