Alexandrite Laser: Versatile Treatment for Hair and Pigmentation

I completely understand why you're curious about this—it's one of the most googled skincare questions out there.

The alexandrite laser (755nm) offers one of the fastest and most efficient wavelengths for treating superficial pigmentation and performing laser hair removal on lighter skin tones. With pulse durations from nanoseconds (Q-switched mode) to milliseconds (long-pulse mode), the alexandrite platform is remarkably versatile. Sessions cost $200 to $600 depending on application, and the 755nm wavelength's strong melanin absorption makes it particularly effective for brown spots, lentigines, and unwanted hair on Fitzpatrick types I-III.

Understanding the 755nm Wavelength

The alexandrite wavelength sits between the shorter wavelengths that target superficial structures and the longer wavelengths that penetrate deeper. At 755nm, it has strong absorption by melanin — approximately three times stronger than the 1064nm Nd:YAG wavelength — making it highly efficient at targeting pigmented structures. This strong melanin absorption is both its greatest strength and its main limitation: while it is extremely effective on light to medium skin, the wavelength is too aggressively absorbed by epidermal melanin in darker skin tones, creating a significant burn risk for Fitzpatrick types IV-VI.

Alexandrite for Pigmented Lesions

And this is where most people get it wrong. In Q-switched mode, the alexandrite laser delivers nanosecond pulses ideal for treating lentigines, ephelides (freckles), café au lait spots, and dermal pigmentation. The 755nm wavelength is particularly effective at targeting blue and green tattoo ink, which absorbs poorly at other commonly available wavelengths. For age spots, a single Q-switched alexandrite session often produces dramatic clearing, with spots darkening, crusting, and shedding within seven to fourteen days. Multiple sessions may be needed for deeper lesions or lesions with both epidermal and dermal components.

Long-Pulse Alexandrite for Hair Removal

In long-pulse mode (millisecond pulse durations), the alexandrite laser is considered the fastest device for laser hair removal on lighter skin tones. Larger spot sizes (up to 18mm) and high repetition rates allow rapid treatment of large areas — a full back can be treated in 20-30 minutes. The strong melanin absorption means effective destruction of the hair follicle with lower energy settings compared to Nd:YAG, improving patient comfort. Most patients require six to eight sessions spaced four to six weeks apart for 70-90% permanent hair reduction. Touch-up sessions may be needed annually to maintain results.

Combining Alexandrite with Other Platforms

Many modern practices use multi-platform laser systems that combine alexandrite with Nd:YAG and diode wavelengths. The Candela GentleMax Pro, for example, offers both alexandrite (755nm) and Nd:YAG (1064nm) in one device, allowing the practitioner to select the optimal wavelength for each patient's skin type and concern. For hair removal, the alexandrite is used on lighter skin tones for efficiency, then switched to Nd:YAG for darker skin tones for safety. For pigmentation, the same flexibility allows treatment of a wider range of conditions and skin types within a single appointment.

Frequently Asked Questions

Is alexandrite laser better than Nd:YAG for hair removal?

For Fitzpatrick skin types I-III, alexandrite is generally more effective and faster than Nd:YAG for hair removal due to stronger melanin absorption. For skin types IV-VI, Nd:YAG is safer and preferred because its longer wavelength bypasses epidermal melanin. For type III skin, either can work well depending on the patient's tanning status and the practitioner's experience.

Can alexandrite laser treat green tattoos?

Yes, the 755nm wavelength is one of the most effective options for green and blue-green tattoo ink, which notoriously resists other wavelengths. Q-switched alexandrite and picosecond 755nm (PicoSure) are the two best technologies for these colors. Six to twelve sessions are typically needed depending on ink density and depth.

How painful is alexandrite laser treatment?

For pigmentation treatment, most patients describe a sharp snapping sensation rated 3-5 out of 10. For hair removal, the built-in cryogen cooling spray on devices like the GentleLase numbs the skin immediately before each pulse, making treatment quite tolerable. Sensitive areas like the bikini line and underarms are more uncomfortable regardless of laser type. Topical numbing cream can be applied for 30-60 minutes before treatment for particularly sensitive patients.

Final Thoughts

The best routine is one you'll actually stick with—don't let perfect be the enemy of good.