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The Effect of Waxing Versus Shaving on the Efficacy of Laser Hair Removal
Abstract
Background:
Excessive hair is undesirable and represents both a social and emotional burden, especially among females. Laser hair removal (LHR) has gained popularity in the past 2 decades. It is a common practice to instruct patients not to pluck or wax their hair before undergoing LHR; only shaving is allowed to improve the efficacy of the LHR.
Objective:
To compare the percentage of hair reduction in preshaved versus prewax epilated axillae after LHR in healthy adult Saudi females.
Methods and materials:
This study is a quantitative experimental pilot clinical trial. Twenty female volunteers were enrolled into this study; all underwent 3 laser sessions using a long-pulsed alexandrite laser. Their left axilla was prewaxed and right axilla was preshaved immediately before laser treatment. Hair was counted manually before and 6 months after the third laser session.
Results:
The right and left axillae both showed significant hair reduction, between the first session and the hair count 6 months after the third laser session. However, there was no statistically significant difference between these 2 means (p = .44).
Conclusion:
There is no statistical difference in hair reduction after LHR whether the area is preshaved or prewax epilated.
... The means of hair follicle density reduction on the low fluence side were 45.9% and high fluence side were 63.7%, respectively (Tables 3, 4). Comparably, the mean VAS pain scores with the high fluence (2.4) were higher than that with the low fluence (2). Plastic surgeon's assessment score was 3.54 on high fluence side, and 3.00 on low fluence side. ...
BACKGROUND: Recent reports indicate that laser hair removal is most effective on anagen hairs. However, no published trials have examined laser epilation after hair cycle synchronization.
OBJECTIVE: To evaluate the potential for enhanced laser hair removal after the induction of telogen hairs into anagen by wax epilation.
METHODS: We identified four 2.5-cm square areas with equivalent hair length and density on the backs of 13 dark-haired white men. To induce typically telogen hairs into anagen, two areas on each patient were wax epilated. Two weeks later, one waxed area and one unwaxed area were treated with a long-pulsed alexandrite laser. One month after laser treatment, a subjective comparison was made based on hair density, length, and thickness.
RESULTS: In 12 of 13 patients, lasered areas that had been pretreated with wax epilation were clearer of hair as compared with areas that had been pretreated by shaving (P = 0.0034). No significant difference was noted between waxed and unwaxed control areas that had not been laser treated (P = 1.0).
CONCLUSION: Wax epilation 2 weeks before laser hair removal improves cosmetic outcomes at 1 month. This effect may be secondary to the recruitment and heightened sensitivity of early anagen hairs.
Suitably brief pulses of selectively absorbed optical radiation can cause selective damage to pigmented structures, cells, and organelles in vivo. Precise aiming is unnecessary in this unique form of radiation injury because inherent optical and thermal properties provide target selectivity. A simple, predictive model is presented. Selective damage to cutaneous microvessels and to melanosomes within melanocytes is shown after 577-nanometer (3 x 10(-7) second) and 351-nanometer (2 x 10(-8) second) pulses, respectively. Hemodynamic, histological, and ultrastructural responses are discussed.
Although many temporary treatments exist for hirsutism and hypertrichosis, a practical and permanent hair removal treatment is needed.
Our purpose was to study the use of normal-mode ruby laser pulses (694 nm, 270 microseconds, 6 mm beam diameter) for hair follicle destruction by selective photothermolysis.
Histologically assessed damage in ex vivo black-haired dog skin after the use of different laser fluences was used to design a human study; 13 volunteers with brown or black hair were exposed to normal-mode ruby laser pulses at fluences of 30 to 60 J/cm2, delivered to both shaved and wax-epilated skin sites. An optical delivery device designed to maximize light delivery to the reticular dermis was used. Hair regrowth was assessed at 1, 3, and 6 months after exposure by counting terminal hairs.
Fluence-dependent selective thermal injury to follicles was observed histologically. There was a significant delay in hair growth in all subjects at all laser-treated sites compared with the unexposed shaven and epilated control sites. At 6 months, there was significant hair loss only in the areas shaved before treatment at the highest fluence. At 6 months, four subjects had less than 50% regrowth, two of whom showed no change between 3 and 6 months. Transient pigmentary changes were observed; there was no scarring.
Selective photothermolysis of hair follicles with the normal-mode ruby laser produces a growth delay consistent with induction of prolonged telogen with apparently permanent hair removal in some cases.
To assess the permanence of hair removal by normal-mode ruby laser treatment.
Hair removal was measured for 2 years after a single treatment with normal-mode ruby laser pulses (694 nm, 270 microseconds, 6-mm beam diameter).
Six test areas on the thighs or backs of 13 volunteers were exposed to normal-mode ruby laser pulses at fluences of 30 to 60 J/cm2 delivered to both shaved and wax-epilated skin. In addition, there was a shaved and wax-epilated control site. Terminal hairs were manually counted before and after laser exposure. Transient alopecia occurred in all 13 participants after laser exposure, consistent with induction of telogen. Two years after laser exposure, 4 participants still had obvious, significant hair loss at all laser-treated sites compared with the unexposed shaved and wax-epilated control sites. In all 4 participants, there was no significant change in hair counts 6 months, 1 year, and 2 years after laser exposure. Laser-induced alopecia correlated histologically with miniaturized, velluslike hair follicles. No scarring and no permanent pigmentary changes were observed.
Permanent, nonscarring alopecia can be induced by a single treatment with high-fluence ruby laser pulses. Miniaturization of the terminal hair follicles seems to account for this response.
An unpredictable response, even in patients with dark hair, often undermines successful ruby laser hair removal. A prospective clinical study was carried out to evaluate the roles of melanin content and growth phases of hair in treatment efficacy. Thirty-six volunteers with white skin and dark hair were recruited for the study, and were all treated using the Chromos 694 Depilation Ruby Laser. The overall efficacy of treatment was assessed at the end of 3 months. The efficacy of laser treatment is not due solely to the proportion of hair in the growing or static phase of the hair cycle. There is a lack of correlation between the melanin content and the overall efficacy of laser hair removal in those treated once, but patients with darker hair responded better after repeated treatments. The proportion of hair in the growth phase and the melanin content of hair do not contribute solely to the efficacy of ruby laser hair removal.
A systematic and logical approach for laser hair removal demands an understanding of its biologic and physical bases. This article presents an overview of hair anatomy and physiology followed by a mathematically nonrigorous review of tissue optics and thermal responses to laser irradiation. The reader is provided with a step by step approach to laser hair removal.
We present a new theory of selective thermal damage of non-uniformly pigmented structures in biological tissues. Spatial separation of the heavily pigmented areas and the target requires limitation of the pigment temperature and heat diffusion from the pigmented to the targeted areas.
A concept of selective target damage by heat diffusion is presented for three target geometries: planar, cylindrical, and spherical. An in vitro experiment is described in which the dependence of thermal damage on pulsewidth at constant fluence was evaluated.
The in vitro experiment showed that the size of the damage zone for similar hair follicles was pulsewidth-independent over a very broad range of pulsewidths (30-400 ms). We formulated a new theory (extended theory of photothermolysis) to interpret the experimental results.
Based on this new theory, the treatment pulsewidth for non-uniformly pigmented targets is significantly longer than the target thermal relaxation time (TRT). The theory provides new recommendations for photoepilation and photosclerotherapy parameters.
Recent reports indicate that laser hair removal is most effective on anagen hairs. However, no published trials have examined laser epilation after hair cycle synchronization.
To evaluate the potential for enhanced laser hair removal after the induction of telogen hairs into anagen by wax epilation.
We identified four 2.5-cm square areas with equivalent hair length and density on the backs of 13 dark-haired white men. To induce typically telogen hairs into anagen, two areas on each patient were wax epilated. Two weeks later, one waxed area and one unwaxed area were treated with a long-pulsed alexandrite laser. One month after laser treatment, a subjective comparison was made based on hair density, length, and thickness.
In 12 of 13 patients, lasered areas that had been pretreated with wax epilation were clearer of hair as compared with areas that had been pretreated by shaving (P=0.0034). No significant difference was noted between waxed and unwaxed control areas that had not been laser treated (P=1.0).
Wax epilation 2 weeks before laser hair removal improves cosmetic outcomes at 1 month. This effect may be secondary to the recruitment and heightened sensitivity of early anagen hairs.
Since 1996, there have been numerous advances in hair laser removal that utilize melanin as a chromophore. All of the devices on the market may be used in patients with light skin (phototypes I-III) and yield hair reduction near 75%. The ruby (694 nm) laser, alexandrite (755 nm) laser, and diode (810 nm) laser, as well as intense pulsed light are commonly used devices for hair laser removal. The long-pulsed Nd:YAG (1064 nm) laser represents the safest device for hair removal in dark-skinned patients because of its long wavelength, although the diode laser, alexandrite laser, and intense pulse light may be used. For treatment of light hair, combination radiofrequency and optical devices as well as photodynamic therapy are under investigation.
Hair removal using a combination radio-frequency and intense pulsed light source
- Yaghami