The active growth phase of a hair follicle — the phase during which your hair is actually getting longer.Anagen duration determines hair length potential and varies by body region (scalp anagen lasts 2–6 years; eyebrow anagen lasts 3–5 months). Anagen is driven by Wnt/β-catenin signaling, IGF-1, and KGF in the dermal papilla. Several compounds in the hair cluster target anagen entry or extension as their proposed mechanism for reducing hair loss or increasing density.