For five years, Kao has worked on Research on Skin Care Linked to Emotions with a focus on stimulation that creates pleasant feelings. Kao extracted 12 emotional factors to evaluate emotions while wearing cosmetics and created an emotional assessment scale. With this scale, it was able to objectively understand changes in the state of mind and emotions while wearing cosmetics. Additionally, in 2017, Kao confirmed that the continuous application of a pleasant touch on the facial skin arouses positive emotions and improves skin appearance, demonstrating the effect of a daily skin care ritual.
Kao recently obtained the following research findings through the Research on Skin Care Linked to Emotions.
1) Salivary oxytocin increases as a result of the application of tactile stimulation that creates pleasant feelings
2) Higher salivary oxytocin level is associated with a higher skin appearance (visual skin condition)
This research was was presented at the 82nd Society of Cosmetic Chemists Japan Research Debate. Based on past research results, Kao will further build on its study of skin care with a focus on the physiological effects of stimulation through the five senses.
Specifically, Kao examined the effect of the physiological changes due to tactile stimulation that creates pleasant feelings on the skin condition under the following testing conditions:
Subjects: 33 women aged 20-49 years without major skin problems
Study method: Saliva was collected before applying tactile stimulation and 4 weeks after the application. Changes in salivary hormones, including oxytocin, were evaluated.
Kao instructed the subjects to continuously apply stimulation on the outer forearm using a cheek brush, which reportedly creates pleasant feelings. Stimulation was applied at a speed of about 3 cm/s, with a load of about 20-40 g, twice a day (morning and night, 3 min/time) for 4 weeks (continuous application of tactile stimulation). Saliva was collected before and after the application of tactile stimulation, and changes in salivary hormones were evaluated.
Study results: It was confirmed that salivary oxytocin increases due to the continuous application of tactile stimulation, which creates pleasant feelings.
Subjects: 89 women aged 20-49 years without major skin problems
• Salivary oxytocin level was measured.
• Participant's skin appearance (visual skin condition) was evaluated using a 7-point response [-3 (most negative) to 3 (most positive)]by sensory experts trained in visual assessment using the evaluation parameters of skin appearance
Evaluation results: A weak positive correlation was demonstrated between the salivary oxytocin level and the skin appearance score (skin texture, skin tone evenness, complexion, and skin surface smoothness)
Study 3 -Confirmatory study to verify the results of study 1 and 2
Kao instructed them to include the following behavior in their skin care routine and repeat the entire course five times: to touch softly the facial skin with the palms of both hands for 30 seconds, remove their hands, and rest for 30 seconds. The following evaluations were conducted before and after the application of tactile stimulation:
• Saliva was collected and the change in the level of oxytocin after the application of tactile stimulation was calculated.
• The evaluated value of pleasant feelings was represented on a 10cm visual analog scale to calculate the difference before and after the tactile stimulation (level of pleasant feelings created by the stimulation).
The results showed a weak positive correlation between the change in salivary oxytocin level and the difference in the evaluated value of pleasant feelings before and after applying tactile stimulation to the facial skin (level of pleasant feelings created by the stimulation). It was suggested that the oxytocin level within the body increases and skin texture improves as more pleasant feelings are created by tactile stimulation during skin care, such as covering the face with the palms.