“There were also highly significant excesses of other recognized adverse effects of niacin, including gastrointestinal, musculoskeletal, and skin-related serious adverse events,” the team at Britain’s Oxford University wrote in their report, published in the New England Journal of Medicine. The studies reveal that although this B vitamin can reduce triglyceride levels, raise “good” cholesterol levels (HDL) and reduce “bad” cholesterol levels (LDL), it does not produce the benefits that patients and their doctors might expect. First, these new studies failed to show that niacin reduced the risk of heart disease and stroke. The studies found that patients taking niacin had about the same rates of heart disease, stroke and death as those who took a placebo pill with no active ingredients. One tested extended-release niacin, and the other evaluated a combination of extended-release niacin and laropiprant, an agent designed to make the niacin more tolerable. Don't take niacin without discussing it with your doctor first because niacin can cause serious side effects when taken in high doses. And they were 9 percent more likely to die, although so few people died that this was hard to measure. In the international study, niacin increased the risk of gastrointestinal events such as diarrhea and ulcers by 28 percent; musculoskeletal problems such as muscle damage and gout by 26 percent; rashes, skin ulcerations and other serious skin-related problems by 67 percent; infections by 22 percent; and gastrointestinal bleeding or other bleeding by 38 percent. One study done in more than 25,000 people in Europe and China showed that while adding niacin to standard cholesterol treatment did lower low density lipoprotein (LDL or “bad” cholesterol), it also was linked with a 32 percent increase in the rate of diabetes over four years. “I think we’ve wasted a lot of money, caused a certain amount of harm.” 
 
 But there’s a huge need for cholesterol-lowering drugs, given that 70 million Americans have unhealthy cholesterol levels. Most doctors no longer recommend niacin for first line cholesterol control — except for people who can't tolerate statins. Start an exercise program, with your doctor's OK. 
 
 What side effects are associated with taking high doses of niacin?
– Niacin sure sounds like a safe drug—it's a B vitamin; you can get it over the counter and in your cereal. And for years, doctors have been prescribing it in the hopes of cutting LDL, or "bad cholesterol," while increasing HDL, or "good cholesterol." But two reports released yesterday indicate that it doesn't reduce the risk of heart attack and stroke at all—but does carry other dangers. One study found that patients who had niacin added to their cholesterol treatments saw their diabetes risk spike 32% over four years, NBC News reports. That's on top of already recognized side effects like stomach ulcers, heartburn, and diarrhea. "I think we've wasted a lot of money, caused a certain amount of harm," by prescribing niacin, one cardiologist said; from 2002 to 2009, niacin prescriptions tripled to 700,000 a month in the US, with sales hitting about $800 million a year. Cardiologists had, however, already begun shying away from the drug in light of earlier research—a 2011 study, for example, indicated that it may increase certain stroke risks. But the Mayo Clinic still recommends niacin, and many doctors agree, Dr. Harlan Krumholz at the New York Times reports. Some doctors point out that the studies focused on high-risk patients, and that niacin could be useful for other patients.