Know Your Laser: Selecting the Right Laser for Hair Removal

Know Your Laser: Selecting the Right Laser for Hair Removal

Laser hair removal is the most common and popular aesthetic laser procedure across the

globe. For individuals suffering from hirsutism or hypertrichosis, or for those who simply wish to reduce hair in certain areas, laser treatments can be highly effective.

How does laser hair removal work?

Laser chromophore spectrum

Laser works by targeting melanin, the chromophore enclosed within the hair shaft. Melanin absorbs the light pulse, converts it into heat which selectively damages the dermal papilla of the hair follicle and its blood supply without harming the surrounding skin.

Types of laser hair removal

Since laser hair removal first made its entrance into the aesthetic market in 1996, laser systems have consistently evolved and improved, allowing an increasingly diverse range of individuals–fair skinned, dark skinned and every skin color in between–to reap the benefits of laser treatments.

Lasers used to remove unwanted hair can be grouped into two general categories

  1. Red light lasers

The shorter wavelength red light systems include the ruby laser, which has a wavelength of 694 nm.

  1. Near-infrared light lasers

These longer wavelength infrared light systems include the alexandrite laser delivering 755 nm, the diode laser delivering 800 nm and Nd:YAG lasers delivering 1064 nm. Longer wavelengths result in less melanin absorption but deeper light penetration, reducing the risk of epidermal damage for darker skin types.

Understanding the general mechanics of each laser device, the candidates best suited to each type and the benefits and disadvantages associated with each is critical to providing informed, ethical advice and treatment for patients who desire removal of their unwanted hair.

In this article we provide you with a brief but comprehensive overview of laser hair removal based on current medical literature.

Ruby laser hair removal

Ruby was the first hair removal laser released onto the market. It is still in use but has mostly been eclipsed by newer lasers that treat a wider range of skin tones and larger surface areas.

When used in non-Q-switched mode, ruby laser emits light pulses that target the hair follicle, causing the hair to fall out, minimizing further growth. Areas with thinner skin, such as the armpits and bikini area appear to respond better than thicker-skinned areas such as the back and chin.



  • Ruby laser is highly unsuitable for patients with tanned or darker skin as the laser can destroy melanin present in the skin, resulting in hypopigmentation.
  • A longer length between pulses (0.85-3 ms) means it takes longer to administer the treatment, and more treatments are generally needed (at least 3, and up to 8 for permanent hair reduction).
  • Slower repetition rate compared to other lasers (0.5 – 1.2 Hz).
  • Ruby laser can only treat a small spot area at a time (3-10mm).
  • Ruby laser is not effective at treating blonde, grey or red hairs.

Alexandrite laser hair removal

The alexandrite laser uses an alexandrite crystal as the laser source. The 755 nm wavelength of high energy light emitted by the laser is converted into heat which damages the hair follicle. Alexandrite lasers cause precise damage to the targeted area and leave surrounding tissue unharmed. Alexandrite lasers are also available in Q-switched mode, allowing the laser to produce a high-intensity beam in very short pulses.

Alexandrite lasers have a higher repetition rate than other lasers and can cover a larger spot size, so they represents an efficient option removing hair from larger surface areas for those with skin types I-III.


  • Excellent for covering larger surface areas (spot size 6-16mm).
  • High pulse repetition rate of up to 5Hz for faster treatment.
  • Excellent penetration rate, meaning fewer treatments needed on average than other lasers.
  • Alexandrite laser has been proven more successful at treating thinner hairs than other lasers, rendering it a good choice for areas where hair is not overly coarse.


  • Inappropriate for patients with tanned or darker-toned skin as the laser may destroy melanin, creating areas of hypopigmentation, or cause blistering .
  • The apidity of the penetration rate means the treatment can be somewhat uncomfortable for the patient.

Diode Laser Hair Removal

Diode lasers deliver a single wavelength of light that has a high abruption rate in melanin. The root and blood flow to the follicle is destroyed by the laser energy, disabling the hair growth permanently while leaving surrounding skin untouched.

The diode laser is one of the newer lasers on the market, with models such as the Lumenis Lightsheer considered by dermatologists and laser hair removal experts to represent the gold standard in laser hair removal. Many diode lasers use vacuum systems that lift the skin (and therefore the hair follicle) closer to the energy source before the light pulse is delivered, resulting in a more comfortable treatment which uses lower fluence levels. Pulse width can vary between 5-30 ms, meaning the treatment is appropriate for both smaller and larger areas.



  • Diode does not work so effectively on thinner or lighter hairs.
  • There are still some risks of scarring and hypopigmentation among darker-skinned patients, though these appear to be temporary.
  • Deeper penetration can mean the treatment is more painful for patients, even with a cooling device. Topical anesthetics such as Lidocaine can be used, particularly when treating larger surface areas and using a higher number of pulses.

Nd:YAG Laser hair removal

Nd:YAG laser uses a neodymium-doped yttrium aluminum garnet crystal as its laser medium. In q-switched mode it can produce two wavelengths: 532nm, and 1064nm. When the laser is delivered at 1064 nm, it can penetrate the skin to the deepest follicles without thermally damaging surrounding tissue, while the 532 nm wavelength can be used to treat finer hair closer to the surface. A carbon lotion is applied to the skin to penetrate the hair follicles that are targeted.


  • The most effective laser for reducing very coarse, thick hair.
  • The Nd: YAG laser protects darkly pigmented epidermis by bypassing it and targeting the hair follicle.
  • As melanin scarcely absorbs Nd:YAG laser light, all skin tones can be treated with this laser, including very dark tones.



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