In theory, there is no exact amount since each face is different, but generally two or three drops the size of a grain of rice should be enough for the entire face. In case of using too much, you may notice a slight feeling of tightness due to the tensing effect of centella; it will disappear with the application of your moisturizing treatment immediately afterwards in your skincare routine. But let's try to avoid exceeding the amount, especially to not waste our serum. Less is more.