This formula worked great for my preemie when she was struggling to gain weight. This was recommended by her pediatrician as a supplement to help her gain weight in combination with breast milk. She continued to use it even after we stopped nursing. It's formula, so it doesn't smell great. And it's really expensive, especially compared to "regular" formula, but it was the only thing that helped my kiddo gain weight when she desperately needed it. The only gripe about this product is you have to dig for the measuring spoon as it is buried underneath all the powder.