Intense pulsed light source (IPLS) treatment for hair removal
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Intense pulsed light source (IPLS) treatment for hair removal

Since time immemorial, ‘body hair’ has caused women enough embarrassment; they have tried and tested hundreds of home remedies and cosmetic therapies to get rid of their hairy look. Some of these proved immensely effective (methods such as shaving, plucking, mechanical and chemical dermabrasion), at least temporarily. The unwanted hair, however, would make a comeback, requiring women to go through another grueling session of hair removal.

Things started looking up with the arrival of the age of cosmetic perfection, when dermatologists and cosmetic surgeons started experimenting with various new methods of hair removal. In their search for newer techniques they evolved methods such as needle and laser epilation. These proved successful in containing the re-growth of body hair for prolonged periods.

Intense pulsed light source (IPLS) epilation treatment, using incoherent light of a broadband spectrum in the range of 500 to 1200 nanometers, is a more recent development in hair removal. Technically, it is not a laser hair removal system – the light involved is not laser light, but, as the name suggests, a very intense pulsating light which has a similar effect to laser light. The success with this treatment lies in the fact that its broad range of technical variables allows the light treatment to be changed (in intensity or the way the light pulses) as appropriate for the nature of the skin and hair follicles to be removed in each individual. It is a highly effective long-term hair reduction method, with very few negative side effects. The device or the Intense Pulsed Light Source is also referred to as a Flashlamp, Epilight or Photoderm VL.

The IPLS (Intense Pulsed Light Source) Treatment

IPLS epilation is based on the principle of selective photothermolysis – the intense pulsed light energy is absorbed by the chromophore, in this case melanin pigment, concentrated in and around the hair follicle bulb. The heat generated in the process destroys the hair follicle as well as the immediate area around it.

The tissue penetration power of visible light depends on the wavelength; in fact, longer wavelengths infiltrate deeper into the skin. The IPLS epilation method uses different cut-off filters (515, 550, 570, 590, 615, 695 and 755 nanometer filters) to adjust or alter the penetration power of the light so that it matches the specific target – both in size as well as skin depth – whether it is hair follicle bulb or its adjoining bulge area. Usage of different cut-off filters, at the same time, helps adjust the treatment parameters in accordance with different skin types.

Pulse duration can also be varied – ranging between 2 and 25 ms; however, under every circumstance the pulse duration has to be less than the thermal relaxation time of the target tissues. Otherwise, the target tissues will cool off between each light pulse, hampering the ultimate effect. The aim is to build up heat in the hair follicle to a high enough level to “cook” and destroy the hair growing cells.

The IPLS technique, at times, requires the use of more than a single pulse. Trains of two to three pulses at regular intervals reasonably enhance the selectivity of the light, so that it focuses on the target hair follicle tissues all the time and is not deflected or scattered in the skin. The size of the IPLS device also plays a vital role in enhancing the selectivity by reducing unnecessary light dispersion.

When taking IPLS treatment, a cooling skin gel is required. The aim is to make the darkly pigmented hair follicles heat up so they become destroyed, but skin beyond the hair follicles should not be affected. The gel performs a dual function – boosting the penetration power of the light into the hair follicles while absorbing the heat from the skin.

The Maastricht Study to Prove the Effectiveness of IPLS System

A study was conducted in the Medical Center, Maastricht, (Netherlands), to test the effectiveness of IPLS system in long-term hair reduction. Seventy hirsute female patients, aged 18 to 67 years chosen at random, were treated with IPLS epilation therapy (using first generation flash lamps).

To begin with, the patients were categorized depending on their skin types (Fitzpatrick I to V). The patients were then asked to shave off the body hair 1 or 2 days before the commencement of the treatment. Patients were also advised to use sun blocker creams for the duration of the treatment. Sun block stops the skin from tanning – this is good for IPLS and laser hair removal as they both work by heating up pigment. If there is pigment in the hair follicles but no pigment in the skin, then the light is much easier to focus on just the follicles to destroy them without affecting the skin. Treatment involved choosing different settings for patients considering their individual skin and hair follicle characteristics. Immediately after treatment, ice packs were applied on the treated areas. Flammazine cream (Silver Sulfadiazine) was applied to control any itchy feeling.

The follow-up treatment was carried out 4 to 6 weeks after the initial treatment. The subsequent treatments were taken up in due course of time depending on the individual hair-growth characteristics of each patient.

Outcome of the Study

To the great satisfaction of the researchers, the study produced favorable and encouraging results. An average of 87% hair reduction resulted after about 8 sittings. (This is an average summation, with some patients requiring as few as 2 sittings while others needed as many as 23 treatments). The whole course of treatment (along with follow up sessions) ranged between 9 and 74 months.

The study established the vital connection between hair reduction and the number of IPLS treatments received. In fact, they are directly proportional, i.e., the more the number of treatment sessions, the higher the hair reduction. Another revelation in this respect is that the greater the time intervals between two subsequent sessions, the more are the chances of inconsistent hair growth.

The study also recognized the relationship between hair reduction, hair pigment and hair quality. It was found that the darker the hair color, the more effective was the IPLS treatment. Actually, the melanin content in light colored hair is far less compared to darker hair. Therefore, the light source fails to target enough chromophore to cause effective hair removal in light colored hair. Hence, the blond and gray haired patients have to undergo extra treatment sessions to obtain similar effects as dark haired people can with fewer sessions.

Another important finding derived from the study is that it is easier to treat fine hair in relation to coarse hair. The thick keratin cover of the coarse hair calls for higher energy levels for effective removal. The pulse-time too plays a vital role in hair reduction. It was observed that with short pulse times, the time required to destroy a hair follicle rises, which eventually causes less hair reduction. Contrarily, longer pulse-times lead to better hair reduction with fewer treatment sessions.


Apart from the Maastricht Study, quite a few research studies have been conducted to ascertain the efficacy of IPL in bringing about satisfactory results in hair removal and long-term hair reduction. While some of these studies employed first-generation flashlamps, others were based on second-generation epilights. The cases might be dissimilar in their approaches as well as in some of their minor findings – differing with the number and frequency of treatment sessions, pulse time, energy level, etc. In essence, however, the outcomes are comparable – the IPLS technique effects permanent hair removal.

The word ‘permanent’ in this study does not imply lifelong, rather denotes a considerable reduction in the number of terminal hairs after being treated with the IPL method, the effect of which outlasts the complete growth-cycle of the hair follicle at a particular body site.

Most of the research studies on IPLS highlight the importance of multiple treatments for satisfactory hair removal. This, because the human hair follows a mosaic pattern of growth and only multiple treatments can fully destroy the hair – shaft, bulb, et al.

The inference that the bulge area in the hair follicle is as much responsible for the re-growth of hair as the hair follicle itself has further emphasized the role of IPLS treatment for effective long-term hair reduction. Complete destruction of the hair follicle and the bulge requires exposure to a safe amount of energy, which permits minimal or negligible negative side effects.

Intense pulsed light source (IPLS) treatment for hair removal references

  • Schroeter CA, Groenewegen JS, Reineke T, Neumann HA. Hair reduction using intense pulsed light source. Dermatol Surg. 2004 Feb;30(2 Pt 1):168-73. PMID: 14756645
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