Comparison of the efficacy and safety of three different depilatory methods

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Comparison of the efficacy and safety of three different depilatory methods

• Henrik Egekvist
• Peter Bjerring
• Thomas Blake

Department of Dermatology, Marselisborg Hospital, University Hospital of Aarhus, Denmark

Correspondence to:
Peter Bjerring, Department of Dermatology, Marselisborg Hospital, University Hospital of Aarhus. P.P. Orumsgade 11, DK-8000 Denmark

 

Abstract:
Three methods of electrical energy-based depilation were compared for safety and efficacy. The protocol used was basically that of the International Guild of Professional Electrologists which is used to define "permanent" hair removal. Ten volunteers had one treatment with each device followed by weekly observations up to 9 weeks. Radio frequency tweezers, direct current tweezers and needle based electrolysis demonstrated reductions in hair counts after 9 weeks of 60.3%, 65.8% and 55.9%, respectively. The differences were not statistically significant. However, large differences in side effects and pain scores existed. The tweezers type epilators both induced pain rated at 13/100 while the needle based depilator induced significant pain at 59/100. Furthermore, acute inflammation and late scarring was seen only following treatment with the electrolysis needle.

 

Conclusion:
The tweezer-type epilators are as effective as needle-based electrolysis but without the pain and side-effects of the latter.

Key words: electrolysis, hair removal, tweezer-type epilator, radio frequency, pain score, scarring

For the last 122 years electrical current has been utilized for removal of unwanted hair (1) Most widespread is the method of electrolysis whereby the electrical current is delivered to the hair follicle by introduction of a needle along the hair shaft into the skin. Hair follicles are destroyed either by the thermal effect of the electric current or by the formation of NaOH resulting from the electrolytic reaction. It is an invasive technique, which is painful (2), and with a potential for side-effects, e.g. inflammatory papule 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 direct current to the hair shaft by electrically conducting tweezers, another applies radio frequency waves similarly (5,6).

Until now only little information has been available by which the relative efficacy and safety of different methods could be judged. Therefore this present investigation was undertaken in order to compare the relative safety and effectiveness of needle-based electrolysis and two different types of tweezer-type epilators.

 

MATERIALS AND METHODS

Volunteers
Ten adult volunteers (7 males and 3 females, mean age 38.3 (23 to 55 years) participated in the study. Here the protocol differed slightly from the IGPE guideline, which restricted the age group to between 20 - 30 years. 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.

Devices

• Needle electrolysis (professional) system: Epilot K2000, Kontron, Germany
• Radio frequency tweezer-type (consumer use) epilator: Finally Free Ultra, Mehl Group Marketing, USA
• Direct current tweezer-type (professional) epilator: Guaranty Hair Removal Epilator 629, Stephens Manufacturing, USA.

Evaluation of Efficacy
For the evaluation of efficacy the basic protocol of the International Guild of Professional Electrologists (IGPE) for evaluation of permanent hair removal was used (7). This protocol defines permanency as at least 40% hair removal after 9 weeks. Recognized by the U.S. Food and Drug Administration as a Performance Standard, it is the basis by which that government agency allows "permanent hair removal" claims for depilatory devices. In contrast to the IGPE protocol, however, no attempt was made to identify and discount anagen hair at 2 weeks, thus causing these study results to be more conservative than would normally be reported.

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 analogue scale (VAS). The value 0 was defined as no pain, and 100 was worst imaginable pain.

Evaluation of side-effects
Inflamed hair follicles (papules) were counted 24 hours after treatment. Side-effects were defined as visible skin changes following the depilatory treatments. These were observed and scored one week after treatment as follows:

• 0: no changes
• 1: <5 papules, no erythema
• 2: 5-10 papules and/or slight erythema
• 3: >10 papules and/or moderate erythema.

Late effects were scored as number of scars present within each test area.

Depilation procedure
On the middle 1/3 of the right lower leg 4 test areas were marked, each containing 50 hairs. A plastic film template was made in order to accurately delineate the individual test areas for subsequent direct hair counting and close-up photography.

The test areas would each be treated with one of the three test devices; a fourth untreated area served as a control. The actual treatment of each area was determined by randomization. The treatments were performed by certified, experienced electrologists according to the manufacturers' guidelines.

Hair counts
Direct hair counts were performed at baseline, then 2 and 9 weeks post-treatment using a plastic film grid and close-up photography. This allowed the counts to be made 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 methods induced a statistically significant reduction in hair number compared to the control area. The variation in efficacy between the three methods were, however, not statistically different. The Finally Free radio frequency device reduced the mean hair count by 60.3%; the Guaranty Hair Removal DC tweezer reduced the mean hair count by 65.8%; and the needle electrolysis system reduced mean hair count by 55.9%. By contrast, the hair count in the control area showed a 3.5% increase in hair number after nine weeks (Tables 1 and 2).

Table 1: Hair Counts at 0, 2 and 9 Weeks after a Single Treatment with Three Hair Removal Devices

Click for Table 1

Summary Table 2: Mean Percent Reduction in Hair Counts Nine Weeks After a Single Treatment with Three Hair Removal Devices

Finally Free	Guaranty Hair Removal	Electrolysis	Control area
60.3%, SD: 19.8%	65.8%, SD: 21.9%	55.9%, SD:21.3%	103.5%, SD:12.7%

Pain associated with the treatments
The pain associated with the three different treatment was scored by each volunteer on a 100 mm long visual analog scale (VAS) just after the treatment. The Finally Free tweezers induced a mean pain score of 13.0, the Guaranty Hair Removal tweezers induced a score of 13.1, and the Kontron needle based electrolysis system induced the highest pain rating of 58.7 (Tables 3 and 4). The pain experienced during treatment with Finally Free was not statistically different from the pain experienced during treatment with Guaranty Hair Removal, but both of these were statistically less painful than the needle based electrolysis.

Table 3: Subjective Pain Rating on a 100 mm Visual Analogue Scale: 0= No Pain. 100 = Worst Imaginable Pain.

Pt. No.	Finally Free	Guarant Hair Removal	Electrolysis
1	8	6	42
2	13	6	94
3	9	8	39
4	9	18	8
5	6	8	88
6	12	17	9
7	22	35	85
8	9	17	49
9	2	5	86
10	40	11	87

Summary Table 4: Mean Pain Scores for Three Hair Removal Devices (0-100)

Finally Free	Guaranty Hair Removal	Electrolysis
13.0, SD: 10.8	13.1., SD: 9.2	58.7, SD: 37.6

 

Safety

Inflammation
Inflammation of the treated follicles (papules) were mainly observed after needle electrolysis ranging from 0 to 51 papules per test area (Table 5).

Table 5: Number of Inflammatory Papules in Each Test Area 24 Hours After a Single Treatment with Three Hair Removal Devices

Pt. No.	Finally Free	Guaranty Hair Removal	Electrolysis	Control
1	1	0	51	0
2	0	0	0	0
3	0	0	16	0
4	0	0	5	0
5	0	0	23	0
6	0	0	8	0
7	4	3	43	0
8	0	0	47	0
9	0	0	31	0
10	0	0	7	0

Severity of Side-Effects
Side-effects were scored according to the following scale:

• 0: no changes
• 1: <5 papules, no erythema
• 2: 5-10 papules and/or slight erythema
• 3: >10 papules and/or moderate erythema.

Late effects were scored as number of scars present within each test area.

Table 6: Side-effect Scores One Week After a Single Treatment with Three Hair Removal Devices

Pt. No.	Finally Free	Guaranty Hair Removal	Electrolysis	Control
1	1	0	51	0
2	0	0	0	0
3	0	0	16	0
4	0	0	5	0
5	0	0	23	0
6	0	0	8	0
7	4	3	43	0
8	0	0	47	0
9	0	0	31	0
10	0	0	7	0

Scarring
At week 9, three volunteers undergoing needle electrolysis demonstrated between 13 and 30 discrete scars. The other two treatments produced no scarring.

 

DISCUSSION

Electrodepilation with either tweezers on a needle inserted directly into the hair follicles applying direct current, high-frequency alternating current or pulsed high-frequency alternating current are -to our best knowledge - the most frequently used electrical methods for depilation. These three methods have been compared in the present study regarding efficacy, and side-effects evaluated as pain, inflammation and scarring associated with the treatment. In the present study, we found no statistically significant difference between the three methods in hair removal abilities nine weeks after a single treatment. Further, all three methods exceeded the standards for "permanent hair removal" as defined by the International Guild of Professional Electrologists and recognized by the FDA. Radio frequency waves applied through tweezers on individual hairs for several seconds provides the most painless method, followed by the tweezer-based direct current. The needle-based, pulsed alternating current is significantly more painful than either of the two other methods. Also, inflammation and scarring is marked with needle-based therapy, but virtually nonexistent with the tweezer devices. Using the present standard observation time of 9 weeks, it is therefore concluded, that electrodepilation with needle-based systems should not be used, because safer and far less painful tweezer-based systems are equally effective.

 

REFERENCES