I just started taking d-ribose Saturday. I'm having some positive and some negative effects, mostly positive, however. I had an immediate effect on my brain and heart. My brain feels more whole and feel less tired and dragged down. However, there is a greater sense of spaciness on and off. Mental clarity is better, but a sense of wooziness (sp ???). My heart palpitations have calmed down radically, but my fluttering seems to have increased. Although, for me fluttering is less stressful that my pounding palpitations. Pounding palpitations still present in evenings, but not as severe. I'm wondering about the experiences of others who have been using it for awhile.