For more than 2,500 years, traditional medicine, especially acupuncture, has been widely used in health care and recognized by the World Health Organization (WHO) to manage various diseases. Besides, many molecular biological mechanisms of acupuncture in pain management have been elucidated. Acupuncture is a safe, effective, and cost-effective therapy, reducing the overuse of opioid pain relievers. In neck pain treatment, many clinical studies used remote acupoints, which have specific effects on the neck. Among them, the Stream points in the Five Stream acupoints system are the most used acupuncture points in the treatment of neck pain. However, the relationship between these acupoints and the neck has not been proven. The goal of this trial is to compare the change in skin surface temperature at the neck and the cutaneous zone before and after using acupuncture at the control acupoint (SP3) and two research acupoints (TB3 and BL65) in healthy volunteers. The main questions it aims to answer are:

• Whether the Zhongzhu and Shugu acupoints change the skin temperature in the neck area?
• How does the change in temperature correlate with the cutaneous zone distribution of the Shaoyang and Taiyang meridians, respectively?

Participants and Methods: The change in skin surface temperature before and after acupuncture at the control acupoint (SP3) and two research acupoints (TB3 and BL65) in healthy volunteers will be compared in a randomized, double-blinded, self-controlled trial. A total of 30 participants will be assigned to 3 groups (A, B, and C), and the allocation will be 1:1:1. Every group will go through three trial stages spaced out by 24 hours, with each stage corresponding to one acupoint on both sides. Group A: In the first trial stage, acupuncture will apply at BL65, the second trial stage at TB3, and the third trial stage at SP3. Group B: In the first trial stage, acupuncture will apply at SP3, the second stage at BL65, and the third stage at TB3. Group C: In the first trial stage, acupuncture will apply to participants at TB3, the second stage at SP3, and the third stage at BL65. The primary outcome of acupuncture at the TB3, BL65, and SP3 acupoints will be the alteration in skin surface temperature at the neck area and the cutaneous zone. The skin surface temperature was measured by an Infrared Thermal Camera brand FLIR C5 and thermal images were analyzed by FLIR Thermal Studio software.

Inclusion Criteria:

• Healthy participants.

• BMI: 18.5 - 23 kg/m2

• Mental alertness, good contact, cooperation with researchers.

• Having no psychiatric stress problem during acupuncture day (confirmed by answering the DASS21 questionnaire with stress points less than 15 points).

• Vital signs within normal limits:

  • Heart rate from 60 to 99 beats per minute.
  • Systolic blood pressure between 90 and 139 mmHg.
  • Diastolic blood pressure between 60 and 89 mmHg.
  • Body temperature: 36.59 ± 0.43 degrees Celsius.
  • Breathing rate: 16 ± 3 breaths per minute.

• Having no disease or using drugs which may change the body temperature.

• Not currently participating in other intervention studies.

• Volunteers who agree to participate and sign the Informed Consent Form, following a detailed explanation of clinical trials.

• Having no acupuncture knowledge yet.

Exclusion Criteria:

• Participate in vigorous physical activities 2 hours before the procedure.
• Taking stimulants (alcohol, beer, coffee, and tobacco) within 24 hours before participating the study.
• Staying up late at night or having a sleep disorder before the procedure
• Women who were in menstruation period, pregnancy, or breastfeeding.
• Having skin injuries, dermatitis-skin infections, or wounds in the area to be investigated.
• Applying chemical or pharmaceutical products to the site of the skin to be investigated before participating the study.
• Using physical therapy, heat therapy, cupping therapy, massage, and acupuncture on the site of the skin to be investigated within 24 hours before participating the study.

Demographic characteristic and outcome data will be shared

Beginning 3 months and ending 1 years after the publication of results

Participants: They did not know about acupuncture, meridian theory, and acupoints. The investigator informs the information about the specific location of the acupoints used and the purpose of the study. The investigator provided a questionnaire to assess the participants' knowledge of meridian and acupressure theory, expectations, and motivation to participate.

Infrared image analyst: The person analyzing the infrared images is not familiar with acupuncture methods. We trained them for two weeks on using FLIR Thermal Studio software and identifying experimental skin areas. After analysis, the infrared image analyst encodes the data and sends it back to the data analyst.

Data analyst: The investigator analyzed the data and was not involved in the randomization and data collection stages.