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What Is the Photothermal Effect In Laser Hair Removal?
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What Is the Photothermal Effect In Laser Hair Removal?

 

The photothermal effect is the process when a material, such as melanin in hair, absorbs light energy and converts it into heat. This heat then creates controlled damage to the targeted area while leaving the surrounding tissue unharmed.

The Photothermal Effect & Laser Hair Removal Efficacy 

In the context of laser hair removal, the photothermal effect is essential for the treatment’s success. The laser emits a specific wavelength of light that is absorbed by the melanin in the hair. This absorption transforms the light into heat, which damages the hair follicle enough to hinder future growth. Because the follicle is heated in a precise and controlled manner, the surrounding skin remains safe.

Choosing the right wavelength is vital for both effectiveness and safety. Shorter wavelengths, such as the 755 nm Alexandrite laser, are absorbed more readily by melanin, making them very effective for lighter skin tones but potentially risky for darker skin due to the chance of skin damage.

On the other hand, longer wavelengths like the 1064 nm Nd:YAG laser penetrate deeper into the skin and are less absorbed by surface melanin, making them a safer option for darker skin tones while still effectively targeting the hair follicle. By selecting the appropriate wavelength, laser hair removal can be customized for various skin and hair types, achieving optimal results with minimal side effects.

SEV’s dual-wavelength laser machines incorporate both technologies to provide safe and efficient treatments for all skin types, maximizing the photothermal effect while ensuring skin protection.

Laser hair removal’s efficacy is also closely linked to the hair growth cycle, as the treatment is most effective when hair is in the active growth phase (also known as the anagen phase). During this stage, the hair follicles contain the most melanin, which absorbs the laser’s energy. This allows the laser to target and damage the follicle effectively, preventing future hair growth.

Unfortunately, not all hairs are in this phase at the same time, which is why multiple sessions are necessary. As some hairs cycle through the growth stages at different times, laser treatments can gradually target each follicle during its anagen phase across multiple visits.

The number of laser sessions needed varies based on individual factors as well as the treatment area, but we normally recommend a minimum of 8 sessions. After a series of sessions, laser hair removal can significantly reduce hair regrowth. Afterward, maintenance treatments help to manage any new hair growth that may occur as a result of hormonal changes.

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