For fine hair, the goal is to smooth the ends and reduce frizz without adding weight or oiliness near the scalp where hair is most prone to looking flat. After washing and towel-drying, start with a very small amount—about the size of a small pea—dispensed onto your palms. Rub your hands together to warm and distribute the serum thinly, then lightly glaze it over the mid-lengths and ends only, avoiding the roots completely. Use a fine-tooth comb or your fingers to help distribute it evenly through the lengths. Since this is a leave-in formula, the conditioning agents will stay on the hair surface. If your hair is particularly fine, you can try applying it only to the very ends as a final step after styling. For day-to-day touch-ups between washes, you can apply an even tinier amount just to dry ends that look frayed. The hydrolyzed keratin and argan extract are designed to coat the hair fiber without a heavy residue, which is why this serum is described as suitable for lengths that need smoothing without weighing them down. Storing it in a cool, dry place away from direct sunlight will help maintain its consistency.