Low HDL my husband just got his bloodwork results back and our doctor wrote that his HDL levels are a bit low (41) (total cholesterol-148, triglycerides-44, and ldl-98). He is underweight for his height (150 lbs 6'4"), does not smoke and is not seditave, s

Given . Given your husband's lack of obesity, lack of smoking, and non sedentary existence, i doubt that you have much to worry about. Only if he has a strong family history of premature coronary disease would i be worried. Niacin can boost hdl. Over the counter preparations are generally not as effective as prescription preparations and are subject to the same serious side effects as the prescription drugs. Niacin is best used under the careful guidance of a physician.
I . I would add that there is recent conflicting research on the use of Niacin to increase hdl, and it is not clear if there is going to be benefit. Time will tell, as there are additional studies currently going on, of whether or not raising HDL can have the significant impact that lowering LDL has. For now i agree that your husband sounds otherwise very healthy. To answer your second question, many of the over the counter "no-flush" Niacin products don't have the dreaded side effect of flushing because they often do not contain the correct active Niacin formulation. In short, not all over the counter products are created equal. It must contain nicotinic acid (such as in slo-niacin) to have any clinical effect.