Efficacy and safety of three electrical depilatory methods

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Efficacy and safety of three electrical depilatory methods

Peter Bjerring and Henrik Egekvist
Department of Dermatology, Marselisborg Hospital, University Hospital of Aarhus, Denmark

Background/aims:
Three electrical depilation methods were compared for efficacy and safety. Ten volunteers received a single treatment with each device followed by weekly observations up to 9 weeks.

Methods:
Radio frequency tweezers, a radio frequency patch and needle based electrolysis were used for treatment of test areas each containing 50 hairs on the lower legs of 10 volunteers. Hairs were counted weekly for 9 weeks after one single treatment and the reduction of hair numbers were compared to a shaved control area.

Results:
The radio frequency tweezers, the radio frequency patch and the needle based electrolysis demonstrated reductions in hair counts after 9 weeks of 55.0%, 62.8% and 54.2%, respectively. All hair reductions were statistically significantly better than the shaved control area. The differences between the three treatment methods were not statistically significant.

The side-effects differed markedly among the three treatments in terms of pain scores and inflammation. The tweezers type depilator induced pain rated by the volunteers as 7.3 on a 0-100 visual analog scale, the patch type depilator induced pain rated as 0.2 on a 0-100 scale while the needle based depilator induced significant pain 53.1 on the 0-100 scale. Acute inflammation was rated as number of inflammatory papules one week after treatment was in average 1.5, 0.8 and 29.6 after radio frequency tweezers, radio frequency patch, and needle based electrolysis, respectively. Late side-effects evaluated as mean number of scars 9 weeks after treatment were 0, 0, and 6.4 after radio frequency tweezers, radio frequency patch, and needle based electrolysis, respectively.

Conclusion:
The tweezers-type radio frequency depilator and the radio frequency patch are as effective as needle-based electrolysis but without the pain and side-effects of the latter.

For more than a century electrical current has been used for removal of unwanted hair (1). The first method to be developed was the needle electrolysis which delivered electrical current conducted to the hair follicle by a needle introduced along the hair shaft into the skin. Hair follicles are destroyed either by a thermal effect or by the formation of the chemically highly active NaOH produced by an electrolytic reaction. It is an invasive technique, which is normally moderately painful (2), and which is also followed by side-effects as inflammatory papules infection, ulceration, and scarring (3,4). More recent hair removal techniques avoid use of a needle by utilizing the conducting properties of the hair shaft to deliver destructive energy to the hair follicle. One method delivers radio frequency waves to the hair shaft by electrically conducting tweezers, another applies radio frequency waves via a high frequency-conducting patch glued to the skin surface (5,6,7).

Until now only little information has been available regarding the relative efficacy and safety of different methods. The present investigation was undertaken in order to compare the relative efficacy and safety of a needle-based electrolysis method, a radio frequency tweezers-type depilator, and a radio frequency patch type depilator.

MATERIALS AND METHODS

Volunteers
Ten adult volunteers (5 males and 5 females), mean age 36.5 years (25 to 56 years) participated in the study. None of the volunteers had any prior skin disease. All participants were of Caucasian origin. The volunteers gave their written informed consent and the study was approved by the Regional Scientific Ethical Committee according to the Declaration of Helsinki.

Depilatory devices
The three electrical energy-based depilatory devices were: 1) needle electrolysis depilator (Epilot K2000, Nemectron, Germany), 2) radio frequency tweezers-type depilator (Finally Free F-130 Ultra E.C. consumer depilator, United Production, USA) and 3) radio frequency patch type depilator (Finally Free Patch , United Production, USA).

Evaluation of efficacy
The evaluation of efficacy was based on the protocol of the International Guild of Professional Electrologists, Inc. (IGPE) for evaluation of permanent hair removal, - a standard protocol recognized by the FDA. This protocol defines permanency as at least 40% of the initial number of hairs still absent after 9 weeks (8).

Evaluation of pain in relation to the depilation procedure
All three depilation types were performed during the same session. Pain was scored immediately after each treatment procedure on a 100 mm visual analog scale (VAS). The value 0 was defined as no pain, and 100 was "worst imaginable pain".

Evaluation of side-effects
Side-effects were defined as visible skin changes at one week and 9 weeks following the depilatory treatments. Immediate side-effects were defined as inflammatory papules (folliculitis) present after 1 week. Late effects were scored at week 9 as the number of scars present within each test area of 50 hairs treated.

Depilation procedure
On the middle 1/3 of the lower legs 4 test areas were marked each containing 50 hairs. A plastic film template was made to accurately delineate the individual test areas for subsequent direct hair counting and close-up photography. Three of the test areas would each be treated with one of the test devices and an area was shaved as a control. The actual treatment of each area was determined by randomization. All treatments were performed by certified, experienced electrologists according to the manufacturers' guidelines.

Hair counts
Hair counts were performed weekly for 9 weeks using a plastic film grid on close-up photographs. All hair counts were performed in a blinded fashion.

Statistics
The ANOVA and the Mann-Whitney's test were used. Significance level: 5%.

RESULTS

Efficacy
After nine weeks, all three depilatory methods statistically significantly reduced the hair number compared to the shaved control area (tweezers depilator: p=0.007, patch depilator: p =0.008, and needle depilator: p =0.003. The variation in efficacy between the three methods were, however, not statistically different. The radio frequency tweezers reduced the mean hair count by 55.0%, the radio frequency patch reduced the mean hair count by 62.8% and the needle electrolysis reduced mean hair count by 54.2%. There was no significant change in the hair count of the control area which showed a 9.6% decrease in hair number after nine weeks (table 1).

Table 1:

Pain associated with the treatments
The pain associated with the three different treatments was scored by each volunteer on 100 mm long VAS scales just after the treatment. The radio frequency tweezers induced a mean pain score of 7.8 mm, the radio frequency patch induced a score of 0.2 mm, and the needle electrolysis system induced the highest pain rating of 53.1 mm (Table 4). The pain experienced during treatment with tweezers was not statistically different from the pain experienced during treatment with the patch, but both of these were statistically less painful than needle electrolysis.

Table 2: Subjective pain rating on a 100 mm visual analog scale: 0= no pain, 100 is worst imaginable pain.

Summary table 3: Mean pain score (0-100)

Safety

The immediate damage to the skin was evaluated by the number of inflammatory papules (folliculitis) (Table 4 and table 5). These were mainly observed after needle electrolysis ranging from 0 to 49 papules per test area (50 hairs treated).

Table 4: Number of inflammatory papules in each test area after 1 week.

Summary table 5: Mean number and standard deviation of inflammatory papules.

Scarring
At week 9, 6 volunteers undergoing needle electrolysis demonstrated between 4 and 23 discrete scars while the other two treatments did not produce any scars (Table 6 and table 7).

Table 6: Late side-effects were scored as number of scars present within each test area at week 9.

Summary table 7: Mean number and standard deviation of scars.

DISCUSSION

Electrodepilation with either tweezers or needles inserted directly into the hair follicles are the most frequently used electrical methods for depilation. Recently, a new device for epilation - the high frequency electro-patch - was developed. These three methods have been compared in the present study regarding efficacy measured as percentage of hairs still gone after 9 weeks and regarding side-effects evaluated as pain, inflammation and late scarring associated with the treatment. In the present study, we found no statistically significant difference in hair removal abilities after nine weeks between the three methods. All three methods exceeded what has been defined by the International Guild of Professional Electrologists Inc. and recognized by the FDA (7) as permanent hair removal. Radio frequency applied through tweezers probing every single hair for several seconds as well as radio frequency applied through an electrically conducting rubber patch attached to the skin treating multiple hairs simultaneously provide equally painless and efficient hair removal. The needle-based, pulsed alternating current is significantly more painful than either of the two other methods, Also, inflammation and scarring is prominent with needle-based therapy, but virtually non-existing with the tweezers device and the patch method. Using the present relatively short standard observation time of 9 weeks, it is therefore concluded, that electro depilation with needle-based systems should not be used, because other, far less painful tweezers-based and patch-based systems are equally effective.

REFERENCES

Address:

Peter Bjerring
Department of Dermatology Marselisborg Hospital
University Hospital of Aarhus P.P. Oumsgade 11
DK-8000 Denmark
Tel: +45 4063 4878
Fax: +45 8741 5123