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| Alexandrite Laser |  Alexandrite lasers for hair removal were approved by FDA and came into the market in the U.S. in 1997. It is rather popular device for treatment. But there's not a lot of data on alexandrites for hair removal.
A short-term study of 130 female subjects had an average of 8 facial treatments over 18 months. Researchers noticed an average 75% reduction for dark hair at 3 months and 10% for light hair. A similar study observed 81% to 95% reduction at 3 months after 3 to 5 treatments. One smaller study noted 86% reduction at 3 months after a single treatment. One comparative research reported 74% reduction at 3 months after 4 procedures. These results were twice better than the results observed with electrolysis. Another short term study observed 19% reduction at 3 months, which compared favorably to Nd:YAG.
A mid-range study noted 25-47% reduction at 4 to 6 months after 1 or 2 procedures in various treated areas. A similar study observed 66% reduction at 1 month, 27% reduction at 3 months, and 4% reduction at 6 months.
One research observing the treatment at the bikini noticed an average of 43% reduction at 6 months plus “one growth cycle” after a single procedure, with 60% of sites having greater than 30%. Another study with five bikini treatments reported 78% reduction at 12 months after final procedure. One research investigated pulsewidths. It compared long and short pulsewidths and noted about 33% reduction at 6 months for both pulsewidths. This was also found in a study observing 60% to 80% reduction at 6 months after 3 procedures. Damage to follicles was proved by one detailed histological analysis.
The results of investigating 150 dark-skinned patients (skin type IV-VI) treated with alexandrite showed that side effects occurred in about 2% of cases. The same happened with light-skinned patients. This is proved by a large-scale study of lighter skin types. Some ways to reduce side effects, such as preheating or precooling the skin before treatment are used.
Epidermal cooling is used to reduce pain and side effects, especially in darker skin. Four types of cooling have been developed:
- Clear gel: usually chilled
- Contact cooling: through a window cooled by circulating water
- Cryogen spray: immediately before/after the laser pulse
- Air cooling: forced cold air at -34 degrees C
It was observed that lower fluences cause higher rates of double hairs as regrowth.
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