Here the question is, “where”? In your skin, hyaluronic acid is crucial. On your skin? It will dry as a film as most polysaccharides, stretching your skin until you rinse it away.
Yours or somebody (some plant) else? Yours give your skin the power to renew, and it’s important to keep your stem cells happy and protected from the sun, strong oxidants, and stress in general. Once the sun or strong oxidant mutates the stem cell’s DNA, that cell and all the cells it will make are changed forever. This is how sunspots and skin cancer happen.
Don’t exist. Or, rather, natural chemicals at concentrations capable of stopping bacteria and fungi will also stop your skin cells from living. You don’t want that.
Again, where? The ceramides your skin cells made while the live cells were transforming into epidermal dead cells will not help you when applied as topical products. They are great at waterproofing the epidermis as “cement” between the dead cells of the stratum corneum. If you try to get natural ceramides in the right amount, they will cost you more than gold and will NOT do a better job than petrolatum.
This insoluble protein is crucial to your skin structure. Fish collagen can be made water soluble by breaking it down into small pieces (peptides) but it’s just a source of amino acids that your skin can make itself. You can add collagen amino acids to your diet if you like chicken soup.
Same thing: an insoluble protein that confers your skin important properties but will do nothing for you is applied topically. Use instead amino acids applied topically.
DNA and RNA
Take care of YOUR DNA by protecting your skin from the sun using sunscreen and antioxidants. Your environment will dictate which DNA is translated into RNA and then expressed as proteins. Any DNA or RNA you apply topically will be broken down quickly and be a source of sugar, phosphate, bases, etc. that your body makes by itself. Your DNA is as unique as you are; apple or whatever DNA will do nothing for you. Unless you are an apple.
Questions? Just ask!