Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Good for circulation

My grandmother used to manage and own a GNC back in the day. She has always been into healthy foods and healthy living. Niacin has always been on the list. It's really good for circulation. Just a caution that even though some say 'flush-free', it may still cause 'flushing'. It feels like ants stinging in the areas where you need it the most. Although it can be an intense tingling, it doesn't last long. It's better if taken with food.