How is a wrinkle smoothing serum different from a moisturizer or an anti wrinkle cream?
The truth is, there's no difference. The word "serum" evokes a sense of medical fluid of some kind, and it sounds so much more scientific than "cream" or "lotion," and creates the impression of a much more scientifically advanced product. It may make you think of blood serum (the plasma or colorless fluid part of the blood). "Serum" is the word used to describe different kinds of injections we're given to prevent against disease.
Technically, a serum is any watery animal fluid. Now how appealing does that sound?
Generally, a wrinkle smoothing serum will contain the same active ingredients as any anti wrinkle skin care product. The difference in formulation is based completely on consistency. A serum will have a lighter feel, more like a gel. This is because they contain silicone rather than other thickening ingredients - and for that reason they feel silky.
Sometimes, a wrinkle smoothing serum will contain glycol or a similar substance that tightens or contracts as it dries. The user feels this tightening sensation on her skin and thinks it's the product working, when it's really just drying out.
Wrinkle smoothing serum as a marketing ploy
Companies that label their product as a "wrinkle smoothing serum" are trying to tap into those positive, scientific associations you have with the term "serum." Generally, these products are much more expensive because the manufacturer is charging a "hype" premium to cover advertising and marketing costs.
There is no difference in effectiveness between a wrinkle smoothing serum and an anti wrinkle cream. The active ingredients, not the method by which they're delivered, is what is important.