Beauty Serum
Beauty serum that we use for our face, contain the highest proportion of active ingredients and, of course, have the most spectacular results in skin care.
Good to Know:
Face serums are designed to prevent or resolve various problems of your skin. Due to high concentration of active ingredients (up to 70%, compared to 10% a cream contains), these products are considered true elixirs. They have a very fine texture; they are easily applied and quickly absorbed by the skin.
The Perfect Choice:
If you want a lighter skin, fresh, and protected against free radicals, Vitamin C is the ingredient that you must use. If your skin needs firmness, you should look after retinol serum, a vitamin A derived, which helps in producing collagen and elastine. For dry skin use hyaluronic acid serums. Serum with fruit acids (AHA or BHA) are excellent for regenerating the skin, by a superficial peeling, also removing the layer of dead cells. Serum containing iridescent particles give skin a higher luminosity.
Use It Properly:
After you have chosen the type of serum according to your needs, use a few drops on face, neck and decolletage. Serum is applied after tonic and before the cream (day or night cream). If you buy the concentrated form (capsules or ampules), manufacturing companies recommend their use only 2 to 4 times per year. Serum is regularly used of up to two times daily; for maximum efficiency.
Worth the Price!
Due to high concentration of active ingredients and effectiveness, serums usually have higher prices than creams. This difference is worth it! Just like the price of “eau de toilette” and “eau de perfume”.

There is also a great answer at Yahoo Answers about the basics on beauty serums as in the tip above: http://tinyurl.com/chgbb2