I tried niacin on the advice of a college at the University of Rochester. She had great success with it. So, I upped my dosage to the multi grams level. There is a small percentage of us that have problems with this level of niacin. After about a week my retinas became swollen and my vision very blurred. I saw a retina specialist and discontinued the gm level dose. After about a week the edema subsided. I know of no way to tell if one is in the do not use group, which is small. This was a good ten years ago so there may be more known by now. It would be worth a search. Additionally, there is a lot of questioning of the entire cholesterol focus. Even as to the causation of heart attacks and stroke it is being questioned. This became a major profit source for our billionaire friends at big Pharma. You should do more research on cholesterol pros and cons. There is a lot of new data. I tried statins once and it clearly and immediately impacted my short term memory. If you do not have a “life extension” or “functional medicine doctor you find them more in tune alternatives to dealing with cholesterol. Is an essential factor in so many bio-chemistry. It is not all bad.