At age 50 you could begin to go up to 1200 mg (still in divided doses of no more than 500 mgs in each dose), though 1000mgs is sufficient with the other supporting vitamins/minerals. The cramps do need to be dealt with and if they are not related to a magnesium deficiency and if your husband is given adequate syntheroid doses to balance out the deficiency then they'll need to look at other causes of the cramps.
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