If a skin care cream or serum could manage the same thing as a medical procedure, then it would be a drug and not cosmetic. This raises the question of how good can skin-applied creams and serums be and how well can they work, given some manufacturer’s claims.
There is the ability for many serums and creams to work; but not "immediately". Nearly all, if not all, work on the basis of continued use. The ingredients of skin care products have improved over time through research and science; this includes what is in the products as much as how to get the bits that work, into the skin. Note that I say into the skin, not into the body. If they were designed to get into the body, then they would not do a lot of good for the skin.
Some time ago, research on pentapeptides was done in relation to wound healing. As part of the body's natural response to helping healing, published studies showed peptides are important in increasing cells in the skin and getting them to produce more collagen.
Despite the marketing, without published medical studies, the question still remains as to whether or not pentapeptide compounds can really be as effective in wound healing inside the body, to anti-ageing effects when used on top of the skin. It is suggested they can, though in a relatively small proportion, hence the need for continued use.
A vital feature, among others, is the size of the molecule which is, in turn, tied to its molecular weight. Most molecules are too large to slip between those cracks between the structure of the skin cells which lie on the surface of the skin; the surface skin cells being dead, of course. Think a solid brick wall - whatever you want to put on it, has to be small enough to fit between the crack *within* the bricks and *within* the cement.
There are some surprising exceptions for example hyaluronic acid can make its way through the skin, when the molecules are small enough, for the smaller molecules will penetrate better. The rule of thumb is that anything smaller than 500 Daltons can penetrate skin while anything larger than 500 Daltons can’t. (A Dalton, for information, is the standard unit that is used for indicating mass on an atomic or molecular scale)
Further, oil soluble ingredients penetrate much better than water-soluble ingredients because the skin itself is, basically, water proof. This is described as the "hydrophile" or "lipophile" balance of the ingredient.
A good example of this is a water soluble alphahydroxy acid, like lactic acid which works on the surface of the skin compared to a more oil soluble beta hydroxy acid, like salicylic acid, which can penetrate into pores to fight acne.
Modern ingredients in products can make a difference in how your skin looks and it's the end result that counts; though one should bear in mind that a sustained and planned beauty regime will produce results and that anything which mentions the word “immediate” should be treated with caution.