When item in inventory regenerate player

If I make a procedure to apply the regeneration effect and put it on "When in inventory tick" on an item, it won't work. That is because the effect is given each tick, so it constantly resets, meaning it doesn't have time to regenerate hearts. I also tried adding half a heart each second, but it makes it so each tick wait a second before giving half a heart, meaning you will get a delayed 1 tick = 1 heart regeneration. Can anyone help me? Thanks