If you're getting such severe cramps that you're in agony or need to take a painkiller, then there's something wrong.
Either you've got endo or something similar, or there's something lacking your diet.
The main culprits are magnesium - the very, very vast majority of women are magnesium deficient. Take a supplement and cramps generally disappear (or alter your diet, even better...).
Another one is essential fatty acids. Evening Primrose Oil capsules taken throughout the cycle can often help massively, and also reduce PMS.
Omega 3 is another key one - most people have plenty of Omega 6 in their diet, but not enough Omega 3. The ideal ratio is 1:1 of 3 to 6, but in most people it's something like 1:20 or 1:30. Krill or Cod Liver Oil are both good supplements.
I used to suffer badly, but since I started supplementing all of those and I changed my diet to zero processed junk food (occasionally I might have one sweet, like once a week, but that's it), plenty of fruit and veges (organic only), and not much red meat - fish once a week - they've gone from being so crippling I'd have to stay home from work for a day, to non-existant, and no PMS.
Cramps are your body telling you to sort yourself out, not put a band-aid on!
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We are a fever, we are a fever, we ain't born typical...