Taking 500 mg l-tyrosine in the morning and mid afternoon to help me deal with the fibro pain and brain fog. I used this years ago for CFS and it pulled me right out of it within a week or two. Then I forgot all about it when I got well. Now I am hoping tyrosine will work its wonders again and help my thyroid and mood and energy. Also have DL phenylalanine to add to it next week if tyrosine doesn't do the job.