Sorry, meant to say magnesium taureate is a good form for absorption.
I don't understand what in magnesium would be destroying your esophagus or causing heartburn. Sometimes if you take too much it can give you diarrhea, but magnesium relaxes the system -- that doesn't mean it cures anxiety, but it does help keep anxiety from making you hurt so much. Now, I wouldn't go advising anyone to go run and take Ativan or any other benzo or any specific medication -- most people really don't need medication but it's very much overprescribed. Therapy, relaxation techniques, learning how to think differently is the first step to take. With natural medicine, no one remedy is generally used -- usually it would be a combination of remedies. But though I don't know of magnesium causing these problems, if they do for you, don't take it. Magnesium is considered a good chelated form of magnesium. It is best absorbed if taken with meals, but for relaxing the muscles and such it's often taken before bedtime. If it's a large tablet or capsule, and magnesium usually is, then you just might have a problem swallowing or your esophagus has been somewhat affected by reflux. This difficult swallowing can cause heartburn.
I have also taken magnesium in the hope it would reduce my anxiety. Whatever benefit it might have in that department isn't worth the heartburn it's apparently causing you. There's no scientific proof magnesium reduces anxiety, at least not that I know of. If you truly need something to help you cope with anxiety, ask your doc for a prescription for Ativan. But you should also see a psychologist/therapist to help you go after the root cause of your anxiety. God bless you!