more research needs to be done (verifying the source) but a quick google review 'Natrol Cognium Review' said that it's a scam. it said the only main ingredient is made from moth silk and the only papers that supports this is a Korean papers. who are known to falsify results (there words). full review is this...
https://www.vaga.org/nootropics/cognium-review/
to improve memory i take fish oil and vitamin d.