The Toppik Hair Fiber clumping is usually due to applying the fibres on wet hair. Your hair is a lot more stable when it is dry as it expands when it is wet. Toppik Hair Fibers were scientifically developed for dry hair. When your hair is wet and expanded, the Toppik Hair Fibres will still join to the hair follicle, but as the hair follicle dries it begins to contract and become smaller due to the water dissolving from within the follicle. Although it is not enough for you to notice it is enough to really put pressure on the keratin bonds. This will quite literally snap the Toppik Hair Fibres, as there are too many bonds in a small space and no-where for the Toppik Hair Fibres to retain their individual bonds.This is not the case when you place Toppik Hair Fibres on dry hair, as even if it were to get wet in the future it would expand with the bonds already in place before contracting and not affecting the bonds overall integrity.