Living Proof Full Thickening Mousse is an ultra, lightweight mousse that provides flexible volume to help fine, flat hair to look, feel and behave like naturally full, thick hair. It is powered by Living Proofs patented Thickening Molecule (PBAE), which creates thickening dots between hair strands so it feels like you have thicker hair. PBAE lasts 5x longer. Full Thickening Mousse: Provides long lasting thickness and fullness Light hold that doesnt collapse or become stiff Full Thickening Mousse is ideal for fine, flat hair. It is silicone-free. Safe and formulated for color and chemically treated hair. The Full System transforms fine, flat hair to look and behave like naturally full, thick hair.