A receding hairline is one of the most recognisable early signs of male pattern hair loss. It often begins around the temples, creating a more pronounced M-shaped or widow's-peak appearance.
Not every change in the hairline means you are going bald. Hairlines can mature naturally. What matters is whether the recession continues to progress, the hairs around the temples become finer, or thinning begins to appear around the crown as well.
If that is happening, the best strategy is usually to act while there is still substantial hair available to protect.