In the case of so-called permanent laser hair removal, the laser acts directly on melanin, which is responsible for hair and skin color. The area to be shaved must be shaved before applying the laser , so that the light emitted by it falls directly on the hair bulb and burns it. But the higher the concentration of melanin, the darker the hair. Hence, this type of technique is not useful when it comes to gray or very light hair, since melanin is absent or very scarce.

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