I just got my d-ribose, "bulk supplements" brand, from amazon, and tried it out. I'm taking it for CFS, and had ordered the first brand i saw because i was having really bad CFS flareups and was desperate. I got it and it tastes like a sugar, which it is, tried a dose... Mild headache as with too large doses of inositol. I'm a little concerned, because I've heard that bulk supplements is a sketchy brand that has had solvents/contaminants in their final products. Thoughts on this/thoughts on better brands? What are good brands for this product and niacinamide and NADH ? How long should it take to see results from d-ribose or other supplements?