Photoepilation: laser or IPL

Learn the details about photoepilation: laser or IPL

The so-called photoepilation group includes laser and intense pulsed light. As the name suggests, this is a hair removal technique using light that eliminates hair follicles through selective photothermolysis.

What is the principle of photoepilation?

Photoepilation is based on photothermolysis, which consists of the selective absorption of light. Translated into hair removal, this means the absorption of light by the hair (target tissue) and its subsequent destruction by thermal effect, respecting the skin (adjacent tissue).

This principle is what destroys the hair without destroying the skin. The light emitted by the laser or intense pulsed light system is attracted to melanin, which is the pigment that gives color to hair and skin. Since hair normally contains a large amount of melanin (more than skin), the light will be absorbed almost entirely by the hair, with little or no heating of the skin.

Differences between laser and intense pulsed light

What differentiates a laser from IPL are basically these three characteristics:

Laser

1. Monochromatic light
2. Unidirectional light
3. Coherent light

IPL

1. Polychromatic light
2. Polydirectional light
3. Non-coherent light

That is, the laser light is of a single color (monochromatic), travels in a single direction (unidirectional) and has almost no divergence (coherent).

In general terms, in terms of photoepilation, if we compare laser with IPL, laser will be more effective on a certain type of hair (usually black and deep hair) but very little on the rest, while IPL will be less effective than laser on that certain type of hair but will be more effective than laser on the rest (fine hair, brown hair, blond hair, etc.).

When is photoepilation indicated?

Photoepilation is indicated in the following cases:

1. Hypertrichosis. This is excess hair in areas that do not follow a male distribution. Hypertrichosis is not hormone-dependent.
2. Hirsutism. It is excess hair in women, following a male distribution. In this way, abundant hair appears in women in areas where only men should have it: chest, back, chin… It is hormone-dependent, so there are hormonal disorders in women that cause hirsutism.
3. Folliculitis. This is an inflammation of the hair follicle. It can be caused by various factors but photoepilation has become the treatment of choice.
4. Unwanted hair. For aesthetic reasons.

Contraindications to photoepilation

There are two types of contraindications, absolute and relative.

Absolute contraindications are

• Newly tanned skin, whether with the sun or with U.V.A.
• Photosensitivity or adverse skin reactions to light exposure, due to disease or drugs.
• Treatment with 13.cis-retinoic acid. It should be abandoned or be without treatment for at least seven months.
• Ocular area, unless there is protection.
• Areas with neoplasms or malignant tumors.

Relative contraindications:

• V or VI skin, depending on which photoepilatory system is used. Skin type V is moderately pigmented and skin type VI is black skin.
• Pregnancy and lactation.
• High risk of keloid or large scars.
• Diabetic patients with decompensated diabetes due to risk of burn ulcers in lower extremities.
• Immunosuppressed patients.
• Patients with recurrent herpes simplex in the area to be treated unless there is a preventive treatment.
• Areas recently depilated by avulsion (wax, tweezers, electric machine…), having removed the existing hair.

Hair that can be depilated

For photoepilation can be carried out must be fulfilled:

1. The hair must contain melanin (pigment).
2. The hair must be darker than the skin.

This means that hair will respond better to photoepilation the blacker it is, followed by brown, blond and gray hair, although the latter will be difficult. White hair, having no melanin, cannot be photoepilated.

The greater the follicular density (the more hair there is) and the more follicles to create new hair, the more sessions will be necessary.

From what age can photoepilation be started?

Specialists in Aesthetic Medicine recommend that, in women, photoepilation can be started from menarche, i.e. when you have your first period. In men, on the other hand, it can be started at the end of puberty. However, it should be noted that there are cases of unwanted hair in which treatment can be started earlier.

What to do before and after photoepilation

1. Avoid tanning, whether by sun or UV-A, at least two weeks before and two weeks after the treatment:

• The greater contrast between skin and hair means more optimal results.
• Newly tanned skin presents an inflammatory process that may respond inappropriately to the effect of the light beam, resulting in hyperpigmentation (areas with more pigmentation than normal skin) or hypopigmentation (areas with less skin coloration).

2. Do not depilate with methods that involve pulling out the hair follicle: wax, tweezers, electric machine…, because if there is no hair it cannot be removed.

3. Shave the area to be photoepilated so that the hair is visible with about 2-3 mm. If it is longer the hair will absorb a lot of energy and the light will not reach the root of the hair. On the other hand, if the hair is between 2-3 mm, the light will reach the root.

Necessary photoepilation sessions

The number of sessions needed to remove the hair will depend on many factors, but will be determined by

• the body area to be depilated
• the presence of hormonal disorders
• skin color
• hair thickness
• hair depth and color
• follicular density
• sex
• age

Broadly speaking, the areas that respond best to photoepilation are the bikini area and underarms, followed by the legs. The areas that respond the worst are the facial and neck areas. That is why the number of sessions needed for bikini line and underarms is no more than 6. The other areas of the body may need more sessions. And on the face there is no specific number of sessions, since, in most cases, reminder sessions will be necessary once or twice a year.

Why several sessions and spaced so far apart?

This is due to the hair growth cycle. Hair has three growth phases: anagen, telogen and catagen.

The first of these is the phase of hair growth in which it is thicker, contains more pigment and is attached to the dermal papilla. This papilla is considered to be the region where the hair and the pigment that gives it color are formed, and it is also responsible for hair growth, thanks to small vessels that nourish the hair through it. For this reason it is believed that in the anagen phase is the moment when the hair is potentially removable, since the light beam would be well absorbed by the hair, preventing the growth of new hair.

However, the percentage of hair in the anagen phase usually ranges between 20-30%, so this is the amount of hair that is usually removed per session. The time it takes for the remaining hair to reach the anagen phase is the time between sessions. However, there are studies that do not defend this position, since in areas such as the bikini, the percentage of hair in the anagen zone is around 30%, being one of the areas with the best response, reaching a loss of 60% of hair in one session. On the other hand, this is not the case in areas such as the upper lip, where the percentage of hair in the anagen phase is around 65%, being, however, one of the areas that requires more treatment sessions.

Another good explanation is related to follicular density (number of hair follicles per cm2), since, in areas such as the upper lip, follicular density is 5 times higher than other areas such as the armpits or English.