Ruby Laser-assisted Hair Removal Research Articles

A review of the ruby laser with reference to hair depilation.

There is a clinical need in the fields of reconstructive and cosmetic plastic surgery for a safe, simple, and effective method of hair depilation. Depilatory clinics have been established throughout the country, commonly using the ruby laser, to treat a cohort of the population, estimated to be between 6% and 10%, recognized as being hirsute. Clinical trials performed to date have not established a protocol that suits the previously mentioned criteria and have been, usually, small in number and short in follow-up. With the increased use that this form of laser treatment will inevitably undergo, it is the belief of the authors that the only way of ascertaining whether the treatment is safe, simple, and effective is first to establish how the ruby laser works. This review relates the knowledge that is currently available regarding the function of the ruby laser to a number of the clinical studies that have been undertaken, including three that have used other types of laser. Using this information, future areas in which research is required can be defined, ultimately to improve the clinical efficacy of ruby laser-assisted hair removal while lessening the current side effects (namely, superficial burning, and hypo- and hyperpigmentation).

Ruby laser-assisted hair removal - correlation of efficacy with the growth cycle of human hair

There is great variation in response when ruby laser is used to remove unwanted body hair. Destruction of hair is often not possible after one laser treatment and the frequency and timing of repeated treatments required to achieve optimum treatment results are unknown. It was the aim of this study to determine whether the efficacy of ruby laser hair removal depended on the hair growth cycle. A prospective clinical study was carried out. The lower legs of 48 patients were treated with the Chromos 694 ruby laser at a standard fluence of 11 Jcm–2. Treatment efficacy was determined as the percentage decrease in hair density at 3 and 7 months. The proportion of growing and resting hairs in the treatment site was assessed by examination of plucked hair roots harvested from areas adjacent to the treatment site. To determine whether examination of plucked hair roots microscopically was reliable in assessing the proportion of growing and resting hairs in a specific site, 7 ex-vivo scalp skins were examined histologically. Results showed that examination of plucked hair roots was a reliable method in assessing the proportion of growing and resting hair. There was no correlation between the treatment efficacy and the growth phases of hair (one way analysis of variance, P=0.116). In conclusion, growing hairs are not more susceptible than resting hairs to ruby laser injury. The clinical implications of this finding are discussed.

Ruby laser-assisted hair removal - long-term results after repeated treatments

The long-pulsed ruby laser has been used to remove unwanted body hair with encouraging results. It is clear from various studies that complete removal of hair is unlikely after a single treatment and diverse response rates have been observed in various individuals. It was the aim of this study to examine the efficacy of ruby laser hair removal after repeated treatments and to assess the patients’ satisfaction with this method of hair removal. In all, 88 patients were treated with the Chromos 694 Depilation Ruby Laser (SLS/Biophile, Wales) at monthly intervals for 4 months and their hair density was measured at 7 and 12 months after the first treatment. The average reduction in hair density was 13.7% at 1 year, which was statistically significant. No adverse long-term side effects were seen. Although only 44.3% of patients had reduced hair count at 1 year, 79.5% patients were satisfied with their treatment. In conclusion, we have shown in this study that the long-pulsed ruby laser is only effective in permanently removing a small proportion of unwanted dark coloured body hair. This method of hair removal is, however, superior to other conventional types of hair removal according to the patients’ subjective observation, because it slows the hair growth, causes thinning of hair, and provides good temporary control of hair from most treatment sites.

Ruby laser-assisted hair removal: an ultrastructural evaluation of cutaneous damage

Ruby laser-assisted hair removal is thought to act via selective photothermolysis of melanin in the hair follicles. Although initial clinical trials of permanent hair removal using ruby lasers are promising, the exact mechanisms of hair destruction and the potential damage to other structures of skin are not known. The aim of this study was to evaluate the cutaneous ultrastructural changes following ruby laser hair removal.Nineteen healthy Caucasian patients with dark (brown/black) hair were treated with the ruby laser and biopsies taken after 0, 2, 3, 5, 7, 14 and 21 days. Specimens were examined by light and electron microscopy.Laser-treated specimens showed widespread coagulation and charring of subcutaneous hair shafts. These obviously damaged follicles were randomly dispersed amongst intact follicles within the same treatment sites. Microscopic changes were also seen in the basal epidermis where melanin was concentrated, irrespective of any obvious macroscopic damage. A low level of inflammatory response seen up to 2 weeks after treatment always followed laser treatment. Suprabasal epidermal necrosis was only seen in patients with blister formation after treatment.Ruby laser irradiation results in selective damage to the hair follicles, with microscopic changes to the basal epidermis. The damage is probably compounded by the inflammatory response to the damaged hair. The normal appearance and distribution of collagen in the dermal layer supported the clinical evidence that laser-assisted hair removal, if performed correctly, does not lead to scar formation.

The effect of ruby laser light on cellular proliferation of epidermal cells.

In ruby laser-assisted hair removal, microscopic damage is often seen in the basal epidermal cells, where melanosomes are concentrated. It is not known whether this treatment leads to cellular hyperproliferation. It was the aim of this study to investigate this. Ten white patients were treated with the Chromos 694-nm Depilation Ruby Laser, and biopsies taken before and after treatments to assess the presence of cell hyperproliferation, which normally accompanies epidermal damage, with immunohistochemical staining of keratin 16 and Ki67. No evidence of cell hyperproliferation was seen in all specimens examined after ruby laser irradiation. The authors conclude that despite the possible microscopic damages seen in the basal epidermis after laser hair removal, there is no evidence of cellular hyperproliferation. This is in contrast to ultraviolet-irradiated cell damage, in which increased basal cell turnover is seen.

Ruby laser-assisted hair removal reduces the coarseness of regrowing hairs: fallacy or fact?

There have been anecdotal reports that hairs that regrow after ruby laser-assisted hair removal are finer in appearance. If true, this phenomenon adds to the improved aesthetic effect of laser treatment of unwanted hair.It is the aim of this study to determine whether this phenomenon indeed occurs, and if so, assess its permanence and its mode of action.In this prospective clinical study, 71 patients with 94 treatment sites were treated with the Chromos 694 Depilation Ruby Laser. Hair diameter was measured pre-treatment, and at 3 and 7 months post-treatment. In addition, ex vivo scalp skin was used to assess if the ruby laser selectively damaged coarser hairs. Laser-treated and matched untreated skin samples were histologically assessed and the diameters of hair shafts (normal or obviously damaged) were measured.Results of this study were analysed using Kruskal–Wallis one-way analysis. There was no statistically significant difference between the hair diameter of non-lasered specimens and the hair diameter of the normal hair in lasered specimens. However, a statistically significant difference was seen between the hair diameter of non-lasered specimens and diameters of damaged hair in lasered specimens (P< 0.05). There was a statistically significant difference (P< 0.05) between pre-treatment and 3 month hair diameters, but no statistically significant difference was found between pre-treatment and 7 month hair diameters.In conclusion, ruby laser-assisted hair removal results in a temporary reduction in hair diameter of regrowing hair. This is not due to the selective targeting of larger hair follicles.

Hair removal using the ruby laser: clinical efficacy in Fitzpatrick skin types I-V and histological changes in epidermal melanocytes.

The ruby laser is effective in removing unwanted body hair. The occurrence of cutaneous side-effects such as blistering, hypopigmentation and hyperpigmentation, however, remains problematic. These side-effects are more commonly seen in patients with dark coloured skin, which partly explains the relative scarcity of information on the efficacy of ruby laser hair removal in such patients. The mechanisms of the occurrence of these side-effects are also not known. It was the aim of this study to evaluate the efficacy of ruby laser-assisted hair removal in patients with Fitzpatrick skin type V in a retrospective clinical study and to evaluate the mechanism of post-treatment pigmentary change in a prospective clinical study. The percentage reduction in hair density in patients with skin type V was assessed after a variable period following treatment with the Chromos 694 Depilation Ruby Laser, and was compared with the results of those with skin types I-IV. To study the pigmentary change and melanocyte numbers after laser irradiation, ex-vivo scalp skin and serial patient biopsies were taken and stained with S-100, dopa oxidase and Masson-Fontana methods. Laser treatment reduced melanocyte numbers as measured by DOPA stain but not by S100. Laser treatment resulted in the clearance of pigment from the epidermis on histology. Ruby laser was shown to be effective in removing unwanted hair from patients with dark coloured skin, but with a higher incidence of cutaneous side-effects. The occurrence of hypopigmentation after laser irradiation was thought to be due to the suppression of melanogenesis in the epidermis rather than to destruction of the melanocytes.

Ruby laser-assisted hair removal success in relation to anatomic factors and melanin content of hair follicles.

Ruby laser-assisted hair removal is thought to work via selective photothermolysis, which relies on light reaching the deeper layers of skin, and the absorption of light by the target chromophore, melanin. It is therefore possible that efficacy of treatment is affected by anatomic factors that determine the amount of light reaching the hair bulbs (i.e., skin color, depth of intracutaneous hair, epidermal thickness and dermal density) and the melanin content of hair. To examine this hypothesis, a prospective study was performed. Forty-eight volunteers were treated with the Chromos 694 Depilation Ruby Laser at a single standard fluence of 11 J/cm2. Treatment efficacy was determined by measuring hair density at 3 and 7 months after treatment. Epidermal depth and dermal density were measured from 2-mm biopsies taken before treatment, and the intracutaneous hair length was determined from plucked hair. Skin color was assessed using a spectrophotometer, and melanin content of dissolved hair was assessed using spectrophotometry. Efficacy of treatment for each patient was compared with the patient's age, intracutaneous hair length, epidermal depth, dermal density, skin color, and total melanin content and relative eumelanin content of hair. No correlation was found between the efficacy of treatment and age and the various anatomic factors. Patients with higher eumelanin content in their hair had better long-term results (Spearman rank test, p = 0.00219). The results suggested that the efficacy of treatment did not depend solely on the amount of laser light penetrating the skin but correlated well with the eumelanin content of hair. The clinical implication of this finding is discussed.

Ruby Laser-Assisted Hair Removal Success in Relation to Anatomic Factors and Melanin Content of Hair Follicles

Ruby Laser-Assisted Hair Removal Success in Relation to Anatomic Factors and Melanin Content of Hair Follicles

The effect of ruby laser light on ex vivo hair follicles: clinical implications.

Several clinical studies on the efficacy of ruby laser-assisted hair removal have reported that regrowth of hair after treatment is common. One of the reasons for the regrowth of hair is the incomplete destruction of germinative hair cells due to the insufficient penetration of the ruby laser in the skin. It was the aim of this study to estimate the extent of damage to the hair follicles after one ruby laser treatment and to determine whether the ruby laser destroyed the bulbs and the bulge regions of hair follicles. The extent of laser damage in hair shafts was determined by serial examination of six specimens of ex vivo scalp skin lasered with the Chromos 694 Depilation Ruby Laser at 14 J per square centimeter and 20 J per square centimeter. Another nine specimens of ex vivo scalp skin were similarly lasered, and monoclonal antibody LP2K was used to identify the bulge regions of the hair follicles using the immunoperoxidase technique. Damage to the bulge region was assessed from consecutive specimens, which were stained with hematoxylin-eosin stain. The mean depth of laser damage sustained by hair follicles was 1.34 mm (14 J per square centimeter) and 1.49 mm (20 J per square centimeter) underneath the skin surface. Most of the laser damage involved the bulge regions but fell short of the hair bulbs. The laser damage did not seem to extend far enough down the hair shafts to result in permanent hair destruction. The clinical implications of this finding are discussed.