<<Disclaimer: Verify this information before applying it to your situation.>> I received ~20 responses and will try my best to summarize as succinctly as possible. Only 2 out of 20 people wrote that they had experienced similar symptoms: sluggish, headachy and lifeless. I actually felt like I was on some sort of drug. Suggestions: check that calcium is GF (mine is), check that I don't have an allergy to something else in the supplement ("classic allergy symptoms"), build up to the 1000 mg (I was taking ~250 mg cal/125 mag in one sitting. One person reportedly nibbles on a supplement all day until it's gone and thereby avoids these symptoms). Someone said that you can only absorb 500 mg of calcium at once. The vast majority of people said that 1000 mg is not too high -- other people's dosages are 1000 mg, 1200 mg, 1500 mg, and even 2000 mg daily. Then there is a tremendous variability in people's thinking about calcium. One person said calcium citrate did not agree with her and that calcium carbonate did. Another person said she takes Oystercal by Natural Wealth with good effect. Another person said you should take calcium citrate, not carbonate or oyster shell. Some people said they take calcium at bedtime (one because she feels that the fiber in a meal interferes with calcium absorption). Another person reported that a dietitian she knows says you should always take calcium with a meal. People report that magnesium, zinc, Vit D, and boron are substances that increase absorption of calcium. Also, making sure you are getting calcium rich foods, like greens, fortified OJ, and some dairy. Alcohol and caffeine decrease calcium in system. Another person said that it took a while to feel better once she started actually absorbing the calcium. There were many brands mentioned, both prescription and nonprescription. One should be careful if you are avoiding starch, maltodextrine, etc., because some brands will contain these. In short, it boils down to checking the ingredients out with the company re GF and starch-free, etc status -- then see how you feel on it. I thank all the people who took the time and caring to respond! Each response was much appreciated. Latimer --- Latimer Kells --- [log in to unmask] --- EarthLink: It's your Internet.