I had tried over the counter melatonin with no results until a doctor recommended this product. It produced immediate improvement in my sleep and I gave it to my dad for Christmas this year. I ran out once and purchased another brand of melatonin at the health food store and it did nothing. So this is a superior product. I originally purchased this on Amazon, but the Earth Turns coupons and free shipping made using their website a no brainier. I was amazed how quickly the product arrived.