studies related to anti - aging are currently being conducted actively around the world , and 
 the related markets are growing fast . in particular , many studies are being conducted on 
 delaying the skin aging process , as people have an increasing interest in changing their 
 external form as well as the functional aspects of their bodies to increase their 
 self - esteem1 .
furthermore , with the 
 development of industry , interest in the effects of air contamination and environmental 
 pollution on the skin and the body is rising , which has led to rising interest in scientific 
 skin management and the introduction of various new skin care devices2 .
skin aging can be classified into two categories : intrinsic aging which develops naturally 
 with age , and aging caused by the external environment3 .
intrinsic aging appears as wrinkles , sagging , and pigmentation , 
 whereas aging caused by the external environment , e.g. ultraviolet rays , wind , coldness , 
 dryness , and tobacco , appears as skin roughness , vasodilatation , actinic keratosis , and 
 solar lentigo , which are generated only in exposed regions4 .
in particular , skin photo - aging by uv rays leads to acute reactions 
 of erythema and edema , which increase the incidence of skin cancer and chronic reactions 
 such as skin pigmentation .
such pigmentation appears when melanin pigments are synthesized 
 excessively in melanin cells exposed to uv rays or when the physiological functions of the 
 skin deteriorate .
when this happens , pigments are deposited in the horny cells of the 
 epidermis , which appear as melasma and freckles5 .
various therapies to improve skin aging are being researched in 
 dermatology , and various laser treatments , chemical peels , surgical treatments , fillers , and 
 botox are being used6,7,8,9 .
the effects of low - level laser therapy ( lllt ) include reduced inflammation , improved 
 lymphedema , relief of pain , and accelerated cell metabolism and cell division , which promote 
 skin regeneration and help facilitate wound healing .
it is also effective in collagen 
 generation , acne treatment , wrinkle improvement , and skin laxity10,11,12,13,14,15,16 .
electroacupuncture ( ea ) has been reported to accelerate 
 the healing of wound tissues , and to elicit anti - inflammation effects , wrinkle improvements , 
 and the reduction of face edema17,18,19 . 

radiofrequency ( rf ) has been reported to be effective at reducing of wrinkles and in the 
 treatment of acne scars by increasing blood circulation and promoting collagen generation , 
 as well as reducing abdominal obesity11 , 20,21,22 .
this study was conducted to observe the effects of lllt , ea , and rf , which are used in 
 physical therapy , on the pigmentation and skin tone of adult women s faces to provide basic 
 data on skin interventions .
the subjects of this study were 30 adult women between 30 and 55  years of age who visited m 
 dermatology hospital in yongin , gyeonggi - do , south korea and who voluntarily agreed to 
 participate after listening to an explanation of the purpose of this study .
the subjects 
 were assigned to a lllt group , ( n=10 ) , an ea group ( n=10 ) , and an rf group ( n=10 ) .
inter - group homogeneity testing 
 for general characteristics before treatment revealed no significant differences .
the characteristics of the subjects are shown in table 1table 1.general characteristicsvariableslllt ( n=10)ea ( n=10)rf ( n=10)age ( yrs)42.8  4.943.4  7.142.9  3.7height ( cm)163.0  7.9158.0  4.3159.8  4.3weight ( kg)56.7  7.558.8  7.252.4
lllt : low - level laser therapy group , rf : 
 radiofrequency group , ea : electroacupuncture group .
lllt : low - level laser therapy group , rf : 
 radiofrequency group , ea : electroacupuncture group for the lllt group , redpulsar ( sometech inc .
, korea ) , which is a diode laser , was used the 
 treatment sessions .
it is a class iiib laser with a wavelength of 635  nm , and power output 
 of 10  mw23 . for the rf group ,
prix iii 
 ( shenb co. , ltd , korea ) was used at a frequency of 1  mhz ( rf energy , maximum 
 450  w / cm ) the treatment sessions24 . for the ea group , disposable stainless steel acupuncture with a 
 size of 0.20 
15  mm was used . for the ea stimulator , an ots h-306 ( hanil tm co. , ltd . , 

korea ) was used with operating conditions of a frequency of 3  hz , 5 seconds of on time , and 
 2 seconds of off time .
ea was performed at a clinical practice by a therapist with 10  years 
 experience .
the intensity of the ea was increased until the subject felt simulation and a 
 little muscular contraction and was then maintained19 . for the skin measurement , janus ( psi co. , ltd .
after the face was fixed 
 at a certain position and external light sources were blocked , the facial skin conditions 
 under irradiation by white light , polarized light and uv light were captured with a canon 
 dslr camera with 10-million pixelresolution . for the measurement of pigmentation and skin 
 tone , the measurement areas were set and measured ratios of each variable . to minimize the 
 measurement errors , the same rater performed measurements from the beginning to the end in 
 similar indoor environments ( room temperature 2021  c and humidity 5060% ) .
all data were coded and analyzed using the statistical analysis program spss ( ver.18 ) .
to 
 determine the post - intervention changes in pigmentation and skin tone in each group , a test 
 of normality was conducted .
if subjects passed the test , a paired samples t - test was 
 conducted ; otherwise , the wilcoxon rank - sum test was performed . to determine the inter - group 
 differences in pigmentation and skin tone ,
one - way anova was used when the data satisfied 
 normality ; otherwise , the significance of differnces was verified by the kruskal - wallis 
 test .
the lllt group showed no significant changes in post - intervention pigmentation ( p>0.05 ) . 

the ea group showed significant decreases in pigmentation in the left and right eye rims 
 ( p<0.05 ) , as well as in left the cheek ( p<0.05 ) .
the rf group showed significant 
 decreases in pigmentation under the left eye ( p<0.05 ) , as well as in the left and right 
 eye rims and the left cheek ( p<0.05 ) .
the inter - group differences in the pigmentation 
 changes were significant for the nose and left eye rim ( p<0.05 ) ( table 2table 2.comparison of the intra - group and inter - group changes in pigmentation among the 
 lllt , ea , and rf groupspigmentationinterventionprepostforeheadlllt12.8  7.012.9  7.1ea16.2  5.315.3  5.4rf12.9  7.613.3  7.3noselllt19.2  8.018.7  7.5ea23.8  7.123.0  6.8rf20.1  9.620.5  9.4under eyesrightlllt26.2  7.525.0  7.2ea24.4  7.023.3  5.7rf23.3  10.521.8  9.3leftlllt24.4  7.722.6  7.1ea27.8  8.325.1  8.0rf23.6  12.722.1  12.7eye rimsrightlllt26.1 
8.725.8  8.6ea25.8  7.722.1  7.6rf24.8  8.923.4  9.1leftlllt26.0  10.325.9  9.2ea26.2  6.422.2  6.3rf27.5  5.624.5  6.3cheeksrightlllt28.5  10.628.4  10.3ea26.6  6.625.6  6.1rf25.7  10.727.4  10.8leftlllt26.7  10.726.7  10.2ea27.9  8.325.7  8.1rf27.2  11.325.8  10.7values are shown as the mean  sd .
* significant difference between ( p<0.05 ) the 
 pre- and post - tests within each group : paired samples t - test , 
 wilcoxon rank - sum test
. lllt : low - level laser therapy , ea : 
 electroacupuncture , rf : radiofrequency , 1 : lllt , 2 : ea , 3 : rf ) .
values are shown as the mean  sd . * significant difference between ( p<0.05 ) the 
 pre- and post - tests within each group : paired samples t - test , 
 wilcoxon rank - sum test .
lllt : low - level laser therapy , ea : 
 electroacupuncture , rf : radiofrequency , 1 : lllt , 2 : ea , 3 : rf the lllt group showed significant increases in skin tone in the forehead and both eye rims 
 post intervention .
the ea group did not show any significant changes in skin 
 tone ( p<0.05 ) .
the rf group showed significant increases in skin tone under the left and 
 right under eyes ( p<0.05 ) .
the inter - group differences in the skin tone changes were 
 insignificant ( p>0.05 ) ( table 3table 3.comparison of the intra - group and inter - group changes in skin tone among the 
 lllt , ea , and rf groupsskin toneinterventionprepostforeheadlllt57.2  2.660.2  2.0ea55.9  3.055.9  3.2rf56.9  3.655.6  3.8noselllt52.8  2.852.7  2.5ea51.8  2.051.4 
2.9rf52.6  3.355.6  3.8under eyesrightlllt46.2  3.847.1  3.9ea47.8  2.847.9  3.1rf47.0  3.048.3  3.9leftlllt47.2  3.848.1  3.6ea48.3  3.048.4  3.4rf47.6  3.249.0  3.5eye rimsrightlllt48.7  5.251.1  5.3ea49.5  3.750.1  3.9rf50.8  3.351.8  3.5leftlllt49.9  4.651.5  4.9ea50.2  3.650.4  4.1rf50.6  3.751.7  4.0cheeksrightlllt50.0  3.650.2  3.2ea49.7  2.248.9  3.5rf50.0  3.350.5  4.1leftlllt51.7  3.951.8  3.9ea50.70  2.750.2  3.5rf51.3  3.551.6  4.03values are shown as the mean  sd .
* significant difference between ( p<0.05 ) the 
 pre- and post - tests within each group : paired samples t - test , 
 wilcoxon rank - sum test .
lllt : low - level laser therapy , ea : 
 electroacupuncture , rf : radiofrequency , 1 : lllt , 2 : ea , 3 : rf ) .
values are shown as the mean  sd . * significant difference between ( p<0.05 ) the 
 pre- and post - tests within each group : paired samples t - test , 
 wilcoxon rank - sum test .
lllt : low - level laser therapy , ea : 
 electroacupuncture , rf : radiofrequency , 1 : lllt , 2 : ea , 3 : rf
aging refers to the physiological phenomenon in which structural and functional changes 
 naturally appear in entities over time . in particular ,
skin aging can be classified into two categories : intrinsic aging 
 caused by genetic programming and aging caused by external environmental conditions , e.g. 
 exposure to uv rays , wind , heat , and tobacco3 , 25 .
the categories of skin aging appear in 
 various forms depending on the region and psychological stress . to overcome this process , 

various efforts to delay the progress of skin aging are being made worldwide , and 
 anti - aging - related markets are growing rapidly1 . in this study , the effects of lllt , ea , and rf on the pigmentation 
 and skin tone of adult women s faces were investigated .
lee et al.23 found that the melanin 
 level significantly decreased after the irradiation by blue o red led light ( p<0.05 ) . 

weiss et al.12 also found that erythema 
 and pigmentation decreased in 90% of subjects . in their study , however , even though the 
 values decreased , the differences were not significant . in an ea experiment with diabetic 
 mice by zhai et al.26 ,
both the erythema 
 index and melanin index of the back skin decreased significantly . in a study by budamakuntla 
 et al.27 ,
the melasma area severity index 
 ( masi ) significantly decreased after microneeding , which was identical to the finding of 
 this study .
kim et al.28 reported that after the 
 application of fractional rf , the melanin index and erythema index improved significantly . 
 in the present study ,
pigmentation significantly decreased under the left eye , and in the 
 right eye rim , the left eye rim , and the right cheek .
budamakuntla et al.27 which compared a tranexamic acid 
 microinjection group and a tranexamic acid with microneedling group , and found the masi of 
 the microneedling group significantly decreased from 9.11  4.09 to 5.06  2.14 
 post - treatment ( p<0.001 ) , but the intergroup differences were not significant .
choi et 
 al.24 compared rf and ultrasound and 
 reported , the rf group showed a significant reduction in pigmentation compared to the 
 ultrasound group . in a study by park et al.29 , the pigmentation of subjects who received microneedle therapy 
 system ( mts ) treatment significantly decreased compared to those receiving rf . in the 
 present study , the ea group showed better effects in terms of nose pigmentation , and
the ea 
 and rf groups showed better results the left eye rim than the lllt group .
lee et al . reported that 14 out of 24 patients experienced an increase in skin tone after 
 being irradiated by red led light23 . 

similarly , in the present study , the skin tone of the lllt group significantly increased in 
 the forehead , the right eye rim , and the left eye rim .
fitzpatrick et al.20 reported improved 
 skin tone after the application of rf . in the present study ,
the rf group showed significant 
 increases in skin tone under the left and right eyes . according to tobin and paus ,
skin tone 
 is generated by a mixture of melanin , hemoglobin , and carotene , with melanin having the 
 greatest effect . in the present study ,
barrett19 also reported that skin tone 
 improved after the application of ea , and fabbrocini et al.31 reported that skin tone significantly increased in 17.4% of a group 
 who received skin needling and depigmenting serum treatment and in 11.2% of a group who 
 received depigmenting serum treatment only . in the present study
, the ea group did not show 
 significant changes in skin tone post intervention .
the reason for this seems to be the 
 differences between previous studies and the present study in terms of the electrical 
 variables of the ea and in the application of serum , which can affect skin tone .
first , the number of subjects was small and only included 
 adult women between 30 and 55  years of age . therefore , the findings of this study can not be 
 generalized .
second , this study was conducted for a short period of only six weeks and the 
 long - term effects were not evaluated . in the future ,
adult women of a broader age group 
 should be studied , and long - term effects of more than six months should be verified .
 [ purpose ] in this study , the effects of low - level laser therapy ( lllt ) , 
 electroacupuncture ( ea ) , and radiofrequency ( rf ) , which are used in physical therapy , on 
 the pigmentation and skin tone of adult women s faces were investigated to provide basic 
 data for skin interventions . 
 [ subjects and methods ] thirty adult females were assigned to 
 either an lllt group ( n=10 ) , an ea group ( n=10 ) , or an rf group ( n=10 ) . 
 the intervention 
 was performed in two 15-minute sessions per week for six weeks . 
 subjects skin tone and 
 pigmentation were observed before and after the intervention . [ results ] the ea group 
 showed significant reductions in pigmentation in the left and right eye rims , as well as 
 in the left cheek . 
 the rf group showed significant post - intervention reductions in 
 pigmentation under the left eye , as well as in the left and right eye rims and the left 
 cheek . 
 the lllt group showed significant increases in skin tone in the forehead and both 
 eye rims . 
 the rf group showed significant increases in skin tone under both eyes . 
 
 [ conclusion ] the application of lllt , ea , and rf had positive effects on pigmentation and 
 skin tone of adult women s faces . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION