Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The best we've tried

My son is on the autism spectrum, and melatonin has helped regulate his sleep cycle. We only use it when he needs it. A factor that made us purchase this brand is that he is on a strict diet because he is gluten intolerant. Other brands of liquid melatonin will add a gluten component to their formulations. We were happy to find out that Source Naturals Melatonin doesn't contain gluten or dairy products, which is why it's the only brand we use at home.