A serum should be applied smack dab in the middle of your daily routine (AM and/or PM), after cleanser, toner, and masks but before moisturizer, facial oils, and sunscreen. Pro tip: Apply serums while the skin is still slightly damp (not soaking wet, though) from cleansing and toning. That’s because damp skin is more permeable and able to absorb the ingredients even more efficiently. Because of the high concentration of active ingredients, 1-2 drops of a serum for the face is usually all you need (instructions, of course, vary. Always consult a product’s label to follow their recommendation). Any more than that and you may experience irritation, redness, breakouts, or sensitized skin. After applying, allow your serums a minute or two to sink in before moving on to the rest of your routine. This gives the formula a chance to penetrate the skin before applying anything else. And since most of us have multiple skin concerns, don’t be afraid to layer different serums together. If you have sensitive skin or are prone to inflammation, keep in mind that certain ingredient cocktails can spark irritation and redness. Learn what ingredients play well together first before mixing and matching.