Introduction to Laser Hair Removal

How Does It Work?

The LightSheer laser emits an intense light at a specific wavelength (810 nanometers, to be precise). Any substance that absorbs this light is heated up by it--but only a few substances in the skin can absorb this wavelength of light. It is very well absorbed by melanin, the main source of pigment in the skin, so anything with melanin in it gets heated up by the light. A hair has more of this pigment in a larger volume than any other part of normal skin. Therefore hairs are heated more than the rest of the skin, and it is possible to destroy the hair without damage to the skin.

Blood also absorbs this wavelength, and individual blood vessels in the skin that are large enough to be seen with the naked eye have enough blood in them that they can be heated and destroyed, too. The LightSheer can actually be used to remove unwanted blood vessels, but there are better options for blood vessel treatment. (For removal of blood vessels see the discussion on our VBeam laser.)

For this particular laser, the "spot size" is 12 mm, so that each time the laser is triggered a square spot 12 mm wide is treated. The laser head is then moved, and another spot is treated--up to 2 spots per second.

Does It Work on All Skin Colors?

If you have very dark skin, special care must be taken to avoid damaging the pigment cells in the skin. Recent advances in lasers permit safe hair removal even in dark-skinned people. The LightSheer is one of the best at this: it has a special cooling tip to keep the surface of the skin cool, and settings can be used that preferentially heat the hair follicles and not the pigment cells in the skin. The way this works is that pigment cells in the skin radiate excess heat faster than the much larger hairs (they have a larger ratio of surface area to volume). If a very long laser pulse is used, the pigment cells radiate the energy almost as fast as they absorb it, while the large hairs keep absorbing it faster than they can radiate it. As a result, the hair heats up much more than the pigment cells in the skin. The ability to deliver a long pulse of energy is a recent and welcome development in hair removal lasers.

The settings that are adjusted for different skin types are:

the total amount of energy delivered (fluence)
the length of time over which that energy is delivered (pulse width)

A tremendous advantage of the LightSheer over older versions of similar lasers is that it has a very much larger range of both fluence (up to 100 joules per square centimenter) and pulse width (up to 400 milliseconds).

How Well Does It Work?

The short answer: it is very effective as long as the hair is not blond, red or white.

The long answer: Skin color and hair color make a difference in how well it works, and in what settings are needed. The easiest person to treat is a dark haired, pale-skinned person. If your hair is white or blonde, the current lasers on the market will not work well for permanent reduction. (To address this lack there is current research ongoing for incorporating a dye into the hair follicle before treating with laser, but the obstacles have not been worked out for this technology yet.)

The darker your skin, the more care must be taken to avoid damaging the normal pigment cells. For this reason, lower power is needed, and/or longer pulse widths. Because of these requirements, more treatments are needed for good results in darker-skinned people and the results are less reliable.

On average, a single treatment with the laser will permanently remove about 30% of the hairs present, which means one treatment is certainly not enough to satisfy most people. For permanent significant hair reduction multiple treatments are needed, generally about 36 treatments. Most people do see see a dramatic reduction in hair after only one treatment, but this dramatic reduction is only temporary. Many of the hair follicles are only "stunned." They regrow in a few months.

Retreatment is usually scheduled 1-3 months after the first treatment.

Remember that you must be very sure that you will not ever want hair in the area treated. Even after a single treatment the density of the hair will be permanently affected. For this reason we are reluctant treat the beard area of men.

What Does It Feel Like?

Each laser pulse causes a stinging sensation. A single pulse is completely trivial, but if a large area is treated (for example, the back, with hundreds of pulses) it can be quite uncomfortable. Also, some areas (such as the lip) are fairly sensitive. There is an easy remedy for this, if desired: an anesthetic cream can be applied, and left on for 30-45 minutes before the treatment. This will make treatment more comfortable, even in large areas. However, the anesthetic cream is fairly expensive, and for large areas such as the legs or back it can add significantly to the cost of the treatment.

The worst of the stinging is over in a few minutes, but a subdued stinging and burning sensation can last for hours.

Redness in the area treated is common, but it usually resolves by the next day. There is generally no interference with any activity desired, although because of possible redness I recommend not scheduling treatment of any visible areas within 2 or 3 days of an important public or social appearance, just in case!

The area to be treated is shaved before treatment. After treatment, dead hairs are often slowly extruded over the following two weeks, and improvement is noticeable after that, even with only one treatment.

So After I Have 4 or 5 Treatments, My Hair Will Be Gone Forever, Right?

Not necessarily.

The great majority of the hairs that have been removed will never grow back. But as the years go by, hair follicles that were previously dormant may be recruited, and some hair regrowth will occur. The number of hairs will be dramatically reduced, and the hairs that do regrow will almost always be thinner, paler, and harder to see.

Do I Have To Alter Any of My Habits Before Laser Hair Treatments?

Possibly.

Tanned skin is harder to treat than non-tanned skin. If you have a suntan, your skin is more easily damaged by the laser, so you are more likely to have some post-treatment discoloration. With the LightSheer we can adjust the parameters to reduce this possibility, but it is still better if you are not tan. We recommend at least 2 months of sun protection before having laser treatments.
If you have a history of herpes simplex in the area treated, the irritation of the laser can activate the infection. Let us know if you have such a history; it is easy to prescribe an antiviral to take before the treatment to reduce such a possibility.
Many medications, including some herbal remedies (e.g., St. John's Wort), can increase photosensitivity. These are very rarely (if ever!) any problem at all, but it is usually easy to stop the medicine for a few days before the laser treatment.
Do not wax before the treatment; this completely undermines the treatment. If there is no hair there, the laser won't treat it. Please don't wax for a couple of months before treatment.
Don't wear makeup or sunscreen when you come in. We will wash it off, anyway, but it's just as well not to have it on. You will need to wear sunscreen after the treatment, if the area treated is in a sun-exposed place: this will reduce the chance of inducing transient skin discoloration.
Do you have any tattoos in the area to be treated? We won't be able to treat directly over a tattoo.

What Are Possible Side Effects, and How Likely Are They?

Pain at the area of treatment during and after treatment. Each laser pulse causes a burning or stinging sensation. Most people find this tolerable even without anesthetic. The area treated may feel like it has had a sunburn for a day or two.
Redness and swelling of the area treated. Nearly everyone gets some redness. It is usually mild, and can easily be covered with makeup if desired. It may last as long as a few days, but that is unusual.
Bruising of the area. This normally does not happen, but it can, especially if there are many dilated veins in the area treated.
Folliculitis (inflammation or infection of the hair follicle). Inflammation around and in the hair follicles is quite common. Most people will have some redness and swelling of the individual hair follicles, because that is where the effects of the laser are most pronounced--the follicle is the target of the treatment. This is usually asymptomatic, but it can itch if you are sensitive to itching. I have seen a patient with prolonged itching for days, which can be quite uncomfortable--it's also quite unusual. Cold compresses and antihistamines may be helpful if this happens. Actual infection of the hair follicle is quite uncommon; this is the same kind of bacterial overgrowth that can happen from shaving.
Crusting or scab formation. Infrequently tiny scabs will form over the follicles.
Change in skin color of the treated area. Hair removal laser treatments can cause decreased or increased pigment in skin in the areas treated; this is more common in darker skin. This is almost always transient (lasting for several weeks), rarely can last months, very rarely it could be permanent. For this reason in very dark-skinned patients we will sometimes recommend a "test spot" be done, in an inconspicuous place. Also, we always start with relatively low settings on the laser to see how the skin responds before moving to higher settings.
Blistering of the treated area. This is quite uncommon. Again, this would be seen in dark-skinned patients or people who are suntanned.
Lack of response. Occasionally the laser treatment will fail to reduce the number of hair follicles or diameter of the hair shafts. A small minority of people have hair that does not seem to respond to laser treatments.
Paradoxical hair growth. There have been unusual cases where the hair becomes either denser or more coarse after laser treatment. Such cases can be successfully retreated with higher energy.
Scarring. This is, so far, only a theoretical concern with respect to diode lasers like the LightSheer--an advantage of the modern hair removal lasers. So far there have not been any case reports of scarring from these lasers. However, it is believed that the potential for scarring exists. For this reason, we ask if you have had any history of abnormal scarring--especially keloids. Special caution would be indicated in a person with a history of keloids, particularly if the person has thick, coarse hair.