I expected it to warm immediately after sticking it to my clothes but it took awhile to warm and its not warm enough to make you feel better from cramps
I always have period cramps and this is my holy grail! This relieves my cramps and help me get my work done without the constant twisting and turning during periods
It did provide some relief, one way or another, but maybe due to the extent of my pain, I did not find it that useful. I was also expecting that it would be hot like the heat packs used for cold weathers, but it's only hot after you peel it. But I guess the herbs/essential oils inside it also help.