Serums are highly potent, containing extensive amounts of active ingredients. Thus with small amounts, you can go a long way, especially with face serums. As a general thumb rule, about pea-sized amounts or two pumps of the face serum is sufficient. If you buy organic serum LosAngeles along with a dropper, it is much better. It will help you control the drops of the serum you are using, and you can always take a drop or two more if required. About three to four drops of your face serum are enough to cover your entire face lightly.