Neurophysiological and Sleep-Related Effects of a Cosmetic Shampoo and Conditioner in Adults With Scalp Discomfort

This was a prospective, single-arm, observational study evaluating the effects of regular use of a cosmetic shampoo and conditioner on scalp comfort, sleep-related experiences, mood, and neurophysiological responses in adults reporting scalp discomfort and sleep difficulties.

Participants were recruited from an internal volunteer database and screened against predefined eligibility criteria. All participants provided written informed consent before any study procedures.

The study consisted of four weekly visits: a baseline visit (EEG, scalp and sleep questionnaires, initiation of Fitbit sleep monitoring), a washout visit one week later with no hair products, followed by two further visits assessing early and extended effects after approximately one and two weeks of product use, respectively. Daily sleep monitoring and weekly questionnaires continued throughout.

EEG recordings were analyzed using Cognalyzer® EEG-based metrics, including mood valence, relaxation, sleepiness, anger, and mental arousal. The primary objective was to evaluate changes in neurophysiological and self-reported measures of scalp comfort, sleep experiences, mood, and well-being following product use; exploratory objectives included sleep-related outcomes and EEG-derived indicators of emotional and cognitive state.

Inclusion criteria

• Age 18 years or older.
• Reported at least one scalp symptom within the past 2 weeks, such as itching, dryness, sensitivity, redness, or flakes.
• Experienced scalp discomfort occasionally or more often during the past 2 weeks.
• Reported a scalp discomfort rating of 4 or higher on a 0-10 scale.
• Reported difficulty falling asleep or staying asleep within the past 2 weeks.
• Experienced sleep difficulty more than once per week.
• Willing and able to use the study shampoo and conditioner at least 3 times per week during the study.
• Willing and able to wear a Fitbit sleep-tracking device during the study.
• Able to attend all scheduled study visits.
• Able to provide informed consent.

Exclusion criteria

• Current use of medicated scalp treatments or use within the previous 14 days.
• Known allergy or sensitivity to ingredients commonly found in shampoos or conditioners.
• Ongoing scalp conditions, including active psoriasis, eczema, or open sores.
• Use of sleep aids, sedatives, antihistamines, or other medications that affect sleep more than once per week during the previous 2 weeks.
• Participation in another clinical, cosmetic, or consumer research study within the previous 30 days.
• Any condition that, in the opinion of the investigators, could interfere with study participation, compliance with study procedures, or interpretation of study results.