they come in several styles and sizes and are anywhere from two inches think to all as six inches and your body will notice the difference right away.
there is another option you can choose if you’re looking to purchase pillow mattress pad and these do not have memory foam. while these are not as comfortable as ones with memory foam they will add that extra padding and cover up an uncomfortable mattress without adding a large bulk to your bed. so if you are having trouble falling asleep and staying asleep through the night simply adding a mattress pad to your mattress may be the solution. 