With the high dose, I could feel the effects right away (my body temperature and appetite shot up, but so did my heartrate and BP). It took a couple of days to feel worsening hypothyroid symptoms on low dose (colder than usual, low heartrate and BP, no sense of hunger, etc).
Ugh.. despite the side effects of high BP and heartrate, I feel so tempted to ingest Lugol's at a high dose again just to increase body temperature.. Cold weather is so harsh on my body. :c