Hair
removal using a combination
of conducted radiofrequency and
optical energies–an 18-month
follow-up
Neil S Sadick & James Shaoul
Introduction
In the past decade, intense pulsed light (IPL) and laser light
sources have proved to be effective for long-term hair
removal.1–8 A high efficiency for dark hair and a relatively
low risk of adverse effects, together with the ability to
treat large areas rapidly, have made photoepilation the
number one procedure in aesthetic medicine. The main
requirement for these devices is the selective thermal
destruction of hairs mediated by melanin-induced absorption
of the light in the hair shaft, while the epidermis
and surrounding tissue absorb light at minimal levels.9,10
There are a number of technologies described in the
literature for photoepilation of light hair phenotypes,
including a number of short wavelength lasers (long-pulsed
ruby (694 nm) and alexandrite (755nm)). Versatile intermediate
wavelength technologies, including the diode
(800 nm) and IPL sources (500–1200 nm), may target
Authors:
Neil S Sadick, MD, FACP, FAACS
Clinical Professor of Dermatology
Weill Medical College of Cornell
University, New York, NT, USA
James Shaoul, MD
Laser light Aesthetics
Ramat-Gam, Israel
Accepted 5 February 2004
Keywords:
photoepilation – IPL/RF – hair
removal
OBJECTIVE: Multiple lasers and intense
pulsed light sources have been
shown to provide long-term hair
removal; however, the management
of all dark skin phenotypes and lightcolored
hair remains problematic.
The present study examined the
long-term photoepilatory effect of
a combined intense pulsed light
(IPL) (680–980 nm)/radiofrequency
(RF) (10–30 J/cm3) light source and
its efficiency for the treatment of
multiple skin phenotypes and varied
hair colors.
METHODS: Forty adult patients (skin
phenotypes II–V) with varied facial
and non-facial hair colors were treated
with a combined IPL/RF technology.
Four treatments were carried
out over a period of 9–12 months at
8–12-week intervals. Light energy
ranged from 15 to 26 J/cm2, while
RF energy varied from 10 to 20 J/cm3.
Hair counts and photographic evaluation
of skin sites were obtained at
baseline, and months 1, 3 and 5 after
the final treatment session. H&E
biopsies were examined at 1 week
in five randomly selected study
cohorts.
RESULTS: Maximum hair reduction
was observed at 6–8 weeks after
each treatment. An average clearance
of 75% was observed in all body
locations at 18 months. No significant
adverse sequelae were reported.
Results showed no significant dependence
on skin color: lighter and
darker skin types responded similarly
to treatment. Histologic evaluation
revealed thermal damage to hair
follicles with vacuolar degeneration.
CONCLUSION: The combined IPL
(680–980 nm)/RF light source with
contact cooling is a safe and effective
method of long-term hair reduction
in patients of diversified skin types
and varied hair colors and is associated
with excellent patient safety.
J Cosmet Laser Ther 2004; 6: 21–26
Correspondence: Neil S Sadick, MD, 772 Park Avenue, New York, NY
10021, USA.
Tel: (z1) 212 772 7242;
E-mail: nssderm@sadickdermatology.com
J Cosmet Laser Ther 2004; 6: 21–26
# J Cosmet Laser Ther. All rights reserved ISSN 1476-4172
DOI: 10.1080/14764170410029013 21
Original Research
many varied hair and skin phenotypes. Long wavelength
technologies, including the 1064 nm Nd:YAG, have been
utilized for the treatment of dark skin, dark hair
phenotypes.11–15
Although most hair types have benefitted from the
presently available technologies, the treatment of blond and
white hair has been particularly problematic due to the low
intensity of target melanin chromophore in the targeted
follicles.16–19 The present study examined the long-term
photoepilatory effect of a new technology which combines
an IPL source (680–980 nm), producing optical energies as
high as 30 J/cm2 with pulse durations as high as 120 ms,
with a bipolar radiofrequency device, which can generate
radiofrequency (RF) energy as high as 20 J/cm3 with a pulse
duration as long as 120 ms, designed to deliver RF electrical
current at a depth of 4mm which can target deep-lying
hair follicles for long-term photoepilation (Aurora Syneron
Medical, Yokneam, Israel). The theory behind this technology
is to decrease optical energy to a level that is safe for
all skin types while compensating for the lack of light by
utilizing an additive energy that is not optical, but is
selectively absorbed by the hair structure.
Materials and methods
Forty adult patients (aged 18–46 years), mean age 38, skin
phenotypes II–V (Table 1) with various hair colors, were
included in the study (Table 2). A variety of facial and torso
body sites were chosen for the study (Table 3). The face was
the most prevalent site treated and studied. Patients were
screened for recent sun exposure (tanning), endocrinopathy
(androgenic or thyroid dysfunction) and isotretinoin
usage. History of previous laser treatments or electrolysis
was also an exclusion criterion. Waxing, bleaching and
depilatory agents were discouraged for 4 weeks prior to
therapy.
Informed consent from all participants was obtained and
the body site to be treated was identified and photographed.
No topical anesthetic agent was applied to treated
body areas.
The target area was shaved prior to treatment. Sequential
digital photographing using identical lighting, patient
positioning and camera equipment (Fujifilm FinePix S2
Pro Digital SLR Camera, Tokyo, Japan) was obtained of all
treatment sites at baseline, and 1, 3 and 6 months after the
last treatment.
The study group of patients received four treatments
over a period of 9–12 months at 8–12-week intervals
(results were monitored to 18 months after the first
treatment or six months after the last treatment). A thin
layer of transparent gel was used for cooling and skin
hydration. Light pressure was applied via the applicator to
the treatment site in order to ensure good coupling of
electrodes to the skin surface. In the study protocol, the
light energy range varied from 15 to 26 J/cm2, set according
to patient skin color phenotypes. On patients and/or body
sites with darker skin types, lower optical energy was used,
while higher optical energy was used on patients and/or
body sites with lighter skin and hair color. Since RF energy
is equally efficient for all hair color and not sensitive to
skin color, different guidelines were utilized: over lower
body areas or skin with dense hair, a lower RF energy was
used – typically 10–14 J/cm3; in all other areas a
higher RF
energy of 18–20 J/cm3 was employed. Contact cooling
(x5‡) was incorporated into the treatment tip.
Two separate hair counts by independent observers using
a 106 illuminated magnifier were performed within a welldefined
3 cm2 region. The following reference landmarks
were utilized in order to achieve uniformity of sequential
hair units: face (pre-auricular sulcus), bikini line (inguinal
area), axillae (mid-axillary line), legs (prepatellar notch)
and trunk (mid-spine).
Percentage hair reduction was defined as the average
number of terminal hair present 1, 3 and 5 months after
treatment compared with the average number of terminal
hairs at baseline. Subjective patient reports and adverse
effects were also recorded at each follow-up visit.
Punch biopsies of 4mm were taken in five individuals 1
week following treatment in order to evaluate changes to
histologic results occurring after IPL/RF pilosebaceous
interaction.
Skin type Number of patients
II 11
III 10
IV 12
V 7
Table 1
Phenotype characteristics of the combined IPL/RF study population
(n~40).
Hair color Number of patients
Black 16
Brown 13
Blond 5
Red 3
White 3
Table 2
Hair color for the combined IPL/RF photoepilation study group
(n~40).
Site Number of patients
Facial 10
Bikini line 7
Axilla 7
Legs 8
Trunk 8
Table 3
Anatomic treatment locations for the combined IPL/RF study group
(n~40).
22 NS Sadick & J Shaoul
Original Research
Results
During the first week after treatment, no significant hair
reduction was observed. Maximum reduction in hair was
observed at 6–8 weeks after each treatment.
Hair density decreased from treatment to treatment as
noted by both patients and investigators. Final clearance
results in different anatomic body locations are presented
in Table 4.
An average clearance of 75% was observed at all
body locations at 18 months. Results showed the best
decrease of 85% for the axillae and legs (Figures 1 and 2).
Other than mild erythema observed in 20% of the treated
patients, which resolved within 1 day post-treatment, no significant
adverse events were noted at each of the follow-up visits.
Results showed no significant dependence on skin color,
as lighter and darker skin types responded similarly to
treatment (Table 4). As expected, darker hair phenotypes
provided greater hair removal efficiency (Table 5).
Histologic evaluation of hair follicles revealed thermal
damage to hair follicles with vacuolar degeneration at
3.5mm noted 1 week following treatment (Figure 3).
Discussion
There are two kinds of light source that provide energy at high
enough levels in order to achieve pan-thermal destruction of
Site Average clearance
Axilla 85%
Bikini line 75%
Legs 85%
Trunk 65%
Face 65%
All anatomic locations 75%
Table 4
Mean hair removal efficiency (MHRE) by anatomic location after four
treatment sessions.
(A) (B)
Figure 1
(A) Before combined intense pulsed light/radiofrequency (IPL/RF) hair
removal; (B) after combined IPL/RF hair removal (four treatments; 6
months following last treatment; brown hair; 85% hair removal
efficiency).
(A) (B)
Figure 2
(A) Before combined intense pulsed light/radiofrequency (IPL/RF) hair
removal; (B) after combined IPL/RF hair removal (four treatments; 6
months following last treatment; black hair; 90% hair removal
efficiency).
Hair color Average clearance
Black 85%
Brown 80%
Blond 60%
Red 60%
White 40%
Table 5
Mean hair removal efficiency (MHRE) by hair color after four
treatment sessions.
Conducted RF and optical energies for hair removal 23
Original Research
hair follicles: lasers and IPLs. In general, owing to the melanin
absorption curve when longer wavelengths are used, both the
treatment efficacy and safety improves.16 Melanin, the
chromophore that gives hair its color and absorbs light, is
present in the epidermis. Both cooling and long-pulse
durations play important roles in decreasing epidermal heating
with minimal impact on treatment results, as they allow the
application of higher fluences of energy.20
Recently, the long-pulse 1064 nm Nd:YAG laser has been
found to be useful for hair removal in all skin types.21–28
This wavelength is not well absorbed by melanin of the
epidermis or hair shaft. To compensate for the lower
absorption level and therefore lower heat generation, higher
energy levels must be utilized at longer pulse durations in
order to maintain safety. However, the methodology is
somewhat limited as pulse duration cannot be increased
infinitely because if it exceeds the target thermal relaxation
time, the heat will dissipate to the surrounding tissue and
will not be localized around the hair shaft.
The technology presented in this study utilizes electrical
optical synergy (ELOS), a new approach combining IPL
(optical) and conducted RF modalities simultaneously
applied to tissue.29 Its advantages in initial clinical trials
show results in areas where purely light-based systems have
not shown significant efficacy; that is, in the treatment of
light hair and dark skin phenotypes. Both forms of energies
are pulsed and delivered to the tissue with a hand-held
applicator.
The light source is a high-power xenon lamp
that is filtered to transmit the wavelength range of
680–980 nm. The conducted RF electrical energy is bipolar
and can generate energy up to 20 J/cm3. RF current flow in
the tissue may be explained by the following equations.
Distribution of electrical current is described by the
continuity equation:
div j~0 (1)
according to Ohm equation:
J~pE (2)
where E is electric field strength, which is described
by the following equation:
E~gradr (3)
where Q is a potential of an electric field.
Combining equations (1)–(3), the following equation for
the potential of an electric field can be obtained:
DivðpgradrÞ~0 (4)
The numerical solution of equation 4 is presented in
Figure 4 for a bipolar geometry with electrode distance of
8 mm.
The maximum current density is on the electrode surface
in contact with the skin. Current density decreases with the
distance from the electrode contact points. As can be seen
from Figure 4, the penetration (where the RF current is 1/e
from the maximum value) is 4 mm.
The basis for the design of the RF electrodes is to deliver
the RF electric current to a depth of 4mm, which can target
the deepest hair follicles in all anatomic locations (Figure 5). In
theory, by using the different types of energies, we can reduce
the optical energy to a safe level that can be used even on darker
skin phenotypes (i.e. Fitzpatrick V and VI). Treatment efficacy
is not compromised, as shown in the present study where 75%
of long-term mean hair removal efficiency (MHRE) at 14
months is similar to that reported with other light-based
technologies because of the use of additional conducted RF
energy that selectively heats the hair follicle. The conducted RF
selectivitymechanism is not based on melanin absorption, and
therefore is not sensitive to skin or hair color.
It should be noted that the theory behind the technology
presented here is based on the principle of selective thermolysis
Figure 3
H&E of hair follicles revealed thermal damage to hair
follicles, with vacuolar degeneration at 3.5mm noted 1 week following
treatment (magnification
680).
24 NS Sadick & J Shaoul
Original Research
similar to other light-based technologies. However, in the
present scenario, parameters of optical and RF energy
(spectrum exposure duration and energy density) are chosen
and optimized to selectively destroy hair follicles without
damaging surrounding tissues. The light is absorbed and
subsequently heats the hair shaft while the RF directly heats the
hair follicle. The combination creates a uniform heat profile
across the hair structure and potentially destroys it9,10
(Figure 6).
These treatments were well tolerated by the subjects,
none of whom utilized topical or other anesthesia.
The only
post-treatment side effect noted in the study population
was transient erythema, which disappeared within 24 hours.
Conclusions
There are multiple lasers and light-based sources available
for the treatment of unwanted hair. Two major
Figure 4
Radiofrequency current relative density as a function of depth, for a
bipolar system with electrodes 4mm apart. The circle represents the
penetration
depth.
Figure 5
The geometry of the radiofrequency (RF) electrodes is designed
to deliver the RF electric current at a depth of 4 mm,
which can target the deepest hair follicles in all anatomic
locations.
Figure 6
Temperature profile of the hair structure.
Conducted RF and optical energies for hair removal 25
Original Research
problematic areas include treatment of light hair hues
and dark skin phenotypes. The findings reported in this
study demonstrate that the combination of optical and
electrical conducted RF energies may be synergistic and
thus effective in providing long-term photoepilation in
multiple skin phenotypes and varied hair colors with a
high safety profile and minimal patient discomfort.
Studies by the author presently in progress show this
technology to be effective in the management of light
blond and white hair phenotypes, although not with the
same hair removal efficiency as noted in the present
study.
In darker skin phenotypes, lower optical energies provide
greater safety without sacrificing efficacy. In lighter colored
hair, the synergistic effect of the two types of energy may
play an important role.
References
1. Lask G, Elman M, Noren P, et al. Hair removal with the
Epitouch ruby laser – a multicenter study. Lasers Surg
Med 1997; 9 (suppl): 32.
2. McDaniel DH, Lord J, Ash K, et al. Laser hair removal: a
review and report on the use of the long-pulsed
alexandrite laser for hair reduction of the upper lip,
leg, back, and bikini region. Dermatol Surg 1999; 25:
425–30.
3. Nanni CA, Alster TS. Long-pulsed alexandrite laserassisted
hair removal at 5, 10, and 20 millisecond pulse
durations. Lasers Surg Med 1999; 24: 332–7.
4. Dierickx CC, Grossman MC, Farinelli WA, et al. Hair
removal by a pulsed, infrared laser system. Lasers Surg
Med 1998; 10 (suppl): 42.
5. Dierickx CC, Grossman MC, Farinelli WA, et al.
Comparison between a long-pulsed ruby laser and a
pulsed, infrared laser system for hair removal. Lasers
Surg Med 1998; 10 (suppl): 42.
6. Grossman M, Dierickx C, Quintana A, et al. Removal of
excess body hair with an 800nm pulsed diode laser.
Lasers Surg Med 1998; 10 (suppl): 42.
7. Weiss RA, Weiss MA, Marwaha S, Harrington A. Hair
removal with a non-coherent filtered flashlamp intense
pulsed light source. Lasers Surg Med 1999; 24: 128–32.
8. Sadick NS, Shea CR, Burchette JL, Prieto VG. Highintensity
flashlamp photoepilation: a clinical, histological
and mechanistic study in human skin. Arch Dermatol
1999; 135: 668–76.
9.
Anderson RR, Parrish JA. Selective photothermolysis:
precise microsurgery by selective absorption of pulsed
radiation. Science 1983; 220: 524–6.
10. Lask G, Elman M, Slatkine M, et al. Laser-assisted hair
removal by selective photothermolysis. Dermatol Surg
1997; 23: 737–9.
11. Nanni CA, Alster TS. A practical review of laser-assisted
hair removal using the Q-switched Nd:YAG, long-pulsed
ruby, and long-pulsed alexandrite lasers. Dermatol
Surg 1998; 24: 1399–405.
12. Grossman MC, Dierickx C, Farinelli W, et al. Damage to
hair follicle by normal mode ruby laser pulses. J Am
Acad Dermatol 1996; 35: 889–94.
13. Gold MH, Bell MW, Foster TD, Street S. Long-term
epilation using the Epilight broadband, intense pulsed
light hair removal system. Dermatol Surg 1997; 23:
909–13.
14. Bencini PL, Luci A, Galimberti M, Ferranti G. Longterm
epilation with long-pulsed Nd:YAG laser. Dermatol
Surg 1999; 25: 175–8.
15. Nururkar V. The safety and efficacy of the long-pulse
alexandrite laser for hair removal in various skin types.
Lasers Surg Med 1997; 10 (suppl): 189.
16. Ross EV, Ladin Z, Kreindel M, Dierickx C. Theoretical
considerations in laser hair removal. Dermatol Clin 1999;
17: 333–55.
17. Orf RJ, Dierickx C. Laser hair removal. Semin Cutan
Med Surg 2002; 21: 129–44.
18. Sadick NS. Laser and flashlamp photoepilation: a critical
review of modern concepts bridging basic science and
clinical applications. J Aesthetic Dermatol Cos Surg 1999;
1: 95–101.
19. Hashizume H, Tokura Y, Takigawa M, Paus R. Hair
follicle dependent expression of heat shock proteins in
hair follicle epithelium. Int J Dermatol 1997; 36: 587–92.
20. Goldberg DJ. Unwanted hair evaluation and treatment
with lasers and light pulse technology. Adv Dermatol
1999; 14: 115–39.
21. Bencini PL, Luci A, Galimberti M, et al. Long-term
epilation with long-pulsed neodimium:YAG laser. Dermatol
Surg 1999; 25: 175–8.
22. Alster TS, Bryan H, Williams CM. Long-pulsed Nd:YAG
laser-assisted hair removal in pigmented skin: a clinical
and histological evaluation. Arch Dermatol 2001; 137:
885–9.
23. Goldberg DJ, Silapunt S. Hair removal using a longpulsed
Nd:YAG laser: comparison at fluences of 50, 80
and 100 J/cm2. Dermatol Surg 2001; 27: 434–6.
24. Ross EV, Cooke LM, Timko AL, et al. Treatment of
pseudofolliculitis barbae in skin types IV, V and VI with
a long-pulsed neodymium:yttrium aluminum garnet
laser. J Am Acad Dermatol 2002; 47: 263–70.
25. Chan HH, Ying SY, Ho WS, et al. An in vivo study
comparing the efficacy and complications of diode laser
and long-pulsed Nd:YAG laser in hair removal in
Chinese patients. Dermatol Surg 2001; 27: 950–4.
26. Fournier N, Aghajan-Nouri N, Barneon G, et al. Hair
removal with an Athos Nd:YAG 3.5 ms pulse laser: a
3-month clinical study. J Cutan Laser 2000; 2: 125–30.
27. Rogachefsky AS, Becker K, Weiss G, et al. Evaluation of
a long-pulsed Nd:YAG laser at different parameters: an
analysis of both fluence and pulse duration. Dermatol
Surg 2002; 28: 932–6.
28. Tanzi EL, Alster TS. Long-pulsed 1064nm Nd:YAG
laser-assisted hair removal in all skin types. Dermatol
Surg 2004; 30: 13–17.
29. Anvari B, Tanenbaum BS, Milner TE, et al. Selective
cooling of biological tissues: application for thermally
mediated therapeutic procedures. Phys Med Biol 1995;
40: 241–52. blog
