The amount of power required for this range to reach the papilla matrix varies with the depth of the follicle pore. There are generally 3 types of hair growth: terminal (deep), secondary (medium) and vellus (shallow). Terminal hairs usually extend 7-8 mm into the dermis and require around 10 Joules per cm2 of photon intensity at the surface of the skin to create adequate thermolysis in the papilla matrix to destroy the tissue(3). Secondary hairs grow to about 5-6 mm in depth and require ≈ 5 Jcm2. The lightest hairs need roughly 2 Jcm2. These 'vellus' hairs are most common on upper lips of adult women and normally respond very well laser epilation.

Faster Than Regular Electrolysis

The advent of this new technology has created enormous excitement in the field of epilation cosmetology, and with good reason. Laser hair removal is simply the fastest way to remove unwanted hair currently available. It is very easy and highly effective. The laser can completely clear the leg hair growth on an average woman in under one hour.  The same area would require more than 40 hours of needle electrolysis.

Discussion
In this study the laser treatments given every six weeks yielded better long-term clinical results than the treatments given every two weeks. Previous studies [1-5] have demonstrated good to excellent results for treatment intervals between four and eight weeks. An earlier study done by the investigators [6] demonstrated excellent long-term hair reduction using three-week treatment intervals. Mathematical modeling showed that better laser penetration was achievable at the hair bulb and bulge in the absence of terminal hair shafts extending to the skin surface. It was recognized that the success of a hair removal treatment at a shortened treatment interval was dependent on the regeneration of melanized target structures for the follow-up treatments [6]  The poor long-term results seen with the shortened treatment interval would suggest that the laser treatment given only two weeks following the initial treatment did not yet have an adequate target to absorb the laser's energy.  It is hypothesized that the hair bulb has not yet regenerated at two weeks and hence the laser treatment was ineffective.  The six-week interval allowed adequate time for the hair bulb and follicle to regenerate therefore providing an adequate target for the laser and hence, a more effective long-term result.
Conclusions
The treatment intervals chosen for laser hair removal strongly affect the efficacy of long-term results. This study demonstrates better efficacy at the six-week treatment interval compared with the two-week treatment interval.
References
1. Bjerring P, Cramers M, Egekvist H, Christiansen K, Troilius A. Hair reduction using a new intense pulsed light irradiator and a normal mode ruby laser. J Cutan Laser Ther  2000; 2: 63-71.
2. Kauvar AN. Treatment of pseudofolliculitis with a pulsed infrared laser. Arch Dermatol 2000; 136:1343-6.
3. Eremia S, Li C, Newman N. Laser hair removal with alexandrite versus diode laser using four treatment sessions: 1-year results. Dermatol Surg  2001; 27: 925-9.
4. Gorgu M, Aslan G, Akoz T, Erdogan B. Comparison of alexandrite laser and electrolysis for hair removal. Dermatol Surg  2000; 26:37-41.
5. Bencini PL, Luci A, Galimberti M, Ferranti G. Long-term epilation with long-pulsed neodimium:YAG laser. Dermatol Surg  1999; 25:175-8.
6. Lloyd JR, Mirkov M. Long-term evaluation of the long-pulsed alexandrite laser for the removal of bikini hair at shortened treatment intervals. Dermatol Surg  2000; 26:633-7

The most favorable results have been achieved by applying laser treatment in the early stages of hair growth (known as the anagen phase). It is during this brief window of opportunity when follicles are small, weak, shallow and highly vulnerable to trauma.

To assure that you are working with new anagen growth, it will be necessary for you to administer a manual follicle extraction (depilatory) to the treatment area (by tweezing or waxing) prior to administration of epilation. Allow 2-3 weeks for new hairs to begin surfacing before moving on to the next step.

At this point, there should be growth emerging from the skin which will look somewhat like the graphic at left. The lightly-colored pointed tip is what you should use to determine which hairs are anagen. Those with jagged or blunt-ended tips are late anagen or catagen phase follicles and do not respond well to electrolysis of any kind. Just pluck these hairs to get them out of the way. They will eventually return in the desirable phase for destruction, usually in 6-8 weeks.

To begin the treatment procedure, it will be necessary to remove all hair from the area by tweezing or waxing.  The use of a waxing kit or wax strips (as shown in the picture) is recommended.  This step is crucial to open the follicle pore for the carbon dye application.

Using a cotton-tipped applicator, completely cover the treatment area with the special carbon-dye included in your kit. Massage the dye into the follicle pore with a firm downward circular motion. Repeat 2-3 times to saturate the follicle pore.  Use an alcohol based wipe to lightly clean the excess dye from the surface of the skin. At this point you should have all desired follicles visibly highlighted with a dark spot. 

Focus the laser at the treatment area. If you are using a laser with a pin-point output, match the angle of growth and focus directly down the highlighted pore. If using an elliptical or square beam, match the angle of growth and scan slowly across the treatment area. The laser will not react with the skin. As soon as it passes over the pore you will see a brilliant flash of light accompanied with some vapor and smoke. You may wish to advise the patient to expect a brief zap (or pinch sensation) while the photons cauterize the pore.

If your patient has a low tolerance for discomfort, you may wish to apply an OTC topical anesthetic prior to treating (such as Dermal-Plast®). Continue to hold the beam over the pore until all activity ceases. Move on to the next follicle, or continue to scan across the treatment area until the photon reaction diminishes.

After the desired area has been completed, apply a cold pack. This will cool the dermis and sooth any uncomfortable neural activity.

Apply the post-treatment gel and advise the patient not to pick or scratch the area. The dermis will show some trauma in the form of eurythmia (reddening) which may last 12-24 hours.

Schedule the patient for their next treatment in 3 weeks. By then some of the new anagen hairs will be surfacing. Hair growth activity will diminish substantially after each application.