Laser hair removal: choosing an installation

At all times, people have tried to get rid of unwanted hair and have invented a huge variety of ways to do this. This includes thread, a razor, sugar paste, wax, strips with different compositions, sharp stones, shells, even scorching with burning oil. But the pain of these procedures was unbearable, and the hair grew back after a certain time.

In the East, a hair was grabbed with a strong thread and pulled out by the roots. The ancient Egyptians applied a special wax paste to the body, covered it with strips of cloth, waited for the wax to harden, and tore it off, removing a large number of hairs at once. This method became the ancestor of modern depilation strips. A honey-based mixture was used on sensitive areas.

In Ancient Greece, tweezers were used, and in Rome, hair was shaved with a narrow blade on a wooden handle.

In the Middle Ages, European women acted differently. The noble ladies who wore closed outfits completely forgot about hair removal on their legs and switched to their faces: a high forehead and a complete absence of eyebrows were in fashion. The latest trend was introduced by the English Queen Elizabeth I. Unwanted hairs were shaved off.

Empress Catherine the Great found the lost recipe for Cleopatra's depilatory cream, the updated composition of which included extracts of Black Forest herbs and thermal waters of Baden-Baden.

In 1760, French barber Jean-Jacques Perret invented the first straight razor. A hundred years later, the Gillette brothers brought the invention to fruition and created a special frame that prevented cuts. A little later, they introduced another innovation that is still used today: replaceable blades.

In 1915, a ladies' magazine first published a photo of a woman with clean-shaven armpits. The photo caused a stir, and the girls immediately ran to stores to buy razors. The fashion for miniskirts and bikinis has led to a demand for hair removal of legs and intimate parts of the body.

In the early 80s, the first home electric epilators began to appear on the market.

In the 11th century, women have freedom of choice and increasingly decide to get rid of unwanted body hair forever.

The new king of hair removal - laser

The word "laser" is an English abbreviation for LASER (Light Amplification by Stimulated Emission of Radiation), which means light amplification using stimulated radiation.

The history of the laser began in 1916, when Albert Einstein developed the theory of the interaction of radiation with matter. During his work, the great scientist suggested the possibility of creating quantum amplifiers of electromagnetic waves. Such an amplifier, designed by N. Basov and A. Prokhorov, enabled physicist T. Meiman to create the first ruby laser in 1960.

Lasers quickly found application in medicine - five years later, surgeon Leon Goldman removed the first tattoos in a similar way. In 1983, American scientists R. Anderson and D. Parrish published the theory of selective photothermolysis in the journal Science, after which laser medicine and dermatology experienced a real revolution.

A laser is a device that produces a light flux of one wavelength (Fig. 1). Light lamps produce a flux consisting of different wavelengths, and among them there are working and non-working ones. Therefore, manufacturers install various filters in these lamps in order to obtain as many working waves as possible at the output, and weed out unnecessary ones. But it will still not be possible to obtain waves of only one length, as in a laser device. And some of the waves emitted by the photo installation will be scattered on the surface of the skin, and some will be perceived by pain receptors, which is why the procedure may be painful. To avoid unpleasant sensations, the power of the rays must be reduced, and at the same time it is not always sufficient to achieve the desired result. This is where the laser wins over photo installations!

According to statistics, among hardware techniques, laser hair removal is the most in demand and brings a stable income. As practice shows, the device is guaranteed to pay for itself in the shortest possible time (from 3 to 10 months), the main thing is the right strategy in working and attracting clients.

Key parameters to consider when choosing a laser:

• power;
• the flash life inherent in the laser emitter and the area of the working spot (parameters that determine the cost of the procedure and the profitability of the device for the owner);
• painless procedure
• laser cost;
• cost of consumables;
• service maintenance.

What lasers are used for hair removal?

For hair removal, red radiation is used, which penetrates deepest into the skin and is well absorbed by melanin. Red radiation is practically not absorbed by lipids, proteins and nucleic acids, therefore it does not activate lipid peroxidation and is not mutagenic.

Radiation suitable for hair removal is provided by:

• ruby laser;
• alexandrite laser;
• neodymium (Nd:YAG) laser;
• diode laser.

Depending on the laser parameters, follicle damage can be photomechanical (in the case of an Nd:YAG laser), when the main destructive factor is the rapid expansion of tissue when heated, or photothermal, when coagulation, charring (carbonization) or evaporation (vaporization) occurs.

It is interesting that, unlike household methods of hair removal, the effect of laser hair removal is prolonged, that is, hair growth continues to be disrupted, and its number decreases after completion of the course of procedures.

Ruby laser

The ruby laser generates red radiation with a wavelength of 694 nm - at maximum absorption by melanin and at weak absorption by hemoglobin. The ruby laser produces light pulses with a duration of about 3 ms, providing an energy flow of up to 40 J/cm2.

The pulse repetition rate of a ruby laser is usually about 1 Hz (one pulse per second), meaning it is a relatively slow laser.

Since the target for this type of laser is exclusively melanin, this type of hair removal is not applicable for tanned skin or for light hair.

The effectiveness of hair removal increases with Fitzpatrick skin types I and II in combination with dark hair. Blonde and red hair, as well as hair on tanned skin or on type IV and V skin, are not removed. Currently, ruby lasers are considered obsolete and are practically not used.

Alexandrite laser

The Alexandrite laser generates radiation with a wavelength of 755 nm, that is, in the region of minimum absorption by hemoglobin and maximum absorption by melanin. The pulse duration is 0.25–300 ms. Alexandrite is a faster laser compared to ruby laser, since the pulse repetition rate is up to 1.5 Hz. The energy flow on the tissue is up to 20–40 J/cm2 per pulse. However, the limitation to skin types I and II according to Fitzpatrick still remains. Also, this laser cannot cope with hair containing a small amount of melanin.

Neodymium laser (Nd:YAG laser)

Widely used in laser medicine for the removal of deep subcutaneous vessels and tattoo removal. The generation of laser radiation is carried out on transitions of neodymium ions (Nd3+), which are built into yttrium-aluminum garnet (YAG) crystals, so it is more often called an Nd:YAG laser.

The Nd:YAG laser emits near-infrared light and has a wavelength of 1,064 nm. This radiation is minimally absorbed by melanin in the upper layers of the skin (that is, such a laser recognizes hair very poorly), but, penetrating into the deeper layers, it is very well absorbed by hemoglobin in the red vessel and oxyhemoglobin in the blue. Pulse duration – 0.25–300 ms, power – up to 300 J/cm2.

The Nd:YAG laser has no restrictions on skin types. Effectively removes blood vessels, but is ineffective for hair removal.

Diode laser

The diode laser generates radiation at a wavelength of 805 nm in the near-infrared spectrum, that is, in the region of complete absorption by melanin.

Pulse duration – from 5 to 400 ms, frequency – up to 2 Hz, energy flow on tissue – up to 100 J/cm2. Diode laser is used for skin types I–V, including people with dark skin types. The diode laser is a non-invasive light therapy device designed specifically for the removal of unwanted hair (even those containing low amounts of melanin) from all areas of the body. Some diode lasers are also designed to treat subcutaneous vessels and spider veins. This is the first laser approved by the FDA for hair removal in teenagers.

The diode laser is the gold standard among all lighting systems in the world. Clinical trials have shown that its effectiveness is several times higher than that of historically earlier types of laser. This means that hair removal requires fewer treatments, takes less time, is more comfortable for the patient, and hair growth stops between sessions. An example of such a laser is the Lumenis LightSheer Desire device.

Read the full version of the article in the magazine Les Nouvelles Esthetiques Ukraine 5 (112)/2018