The Kérastase Première Sérum Filler Fondamental is a lightweight, leave-in hair serum engineered for the deep inner repair of all damaged and chemically processed hair types, delivering a visibly glossy, supple, and resilient finish with every use. Processed hair is significantly more porous than untreated hair, causing it to absorb up to three times more calcium from water, which leads to a damaging calcium overdose that weakens the hair fiber from the inside out and dulls its surface appearance. This advanced serum works at the core of each strand to neutralize that calcium buildup, reinforce the hair's internal structure, and restore its natural elasticity and shine without weighing it down. Ideal for daily use on color-treated, bleached, heat-styled, or chemically processed hair, it leaves every strand feeling nourished, protected, and beautifully smooth from root to tip.
