1. Molecular weight
If the molecular weight is too large, it is not easy to be absorbed by the human body, and if it is too small, it is unstable and affects the effect.
Some best fish collagen powder products are sold under the slogan of hundreds of Daltons, which is actually exaggerated propaganda. The editor recommends: the more suitable molecular weight should be 1000-3000 Daltons!

2. No Addition
Oral collagen products, in order to increase the taste, some manufacturers will add some different additives, such as various flavors, to cover up the fishy smell of fish collagen, and make fish collagen powder with different flavors to attract consumers. 
However, additives are potentially harmful to the human body, so we should not choose impure fish collagen powder just for the sake of taste!
The best fish collagen powder has a slight fishy smell. We can adjust the flavor by matching with honey, milk, etc., so that it is correct to eat.