The purpose of this study is to compare the differences in various chemical and biologic parameters of scalp and and hair parameters between young and old Caucasian females. The hair state and scalp blood flow in younger and older age groups with typical hair care practices will be qualified by measuring various parameters of the hair shaft and scalp with correlation back to hair and scalp satisfaction as measured in the subject. This is a single center study with an anticipated 4 month enrollment period. The investigators will compare various scalp and hair parameters between young and old Caucasian females by obtaining the following biological and chemical/structural information. Hair growth rate, anagen to telogen ratio, hair density (determined via phototrichogram and digital imaging), Vascular blood flow (Laser Doppler Flowmetry), Histamine stimulation and Hair diameter (clipped hairs). In addition, a detailed questionnaire will be administered to each subject regarding satisfaction of the subject's hair state, including typical hair care regimens and symptoms in scalp and/or hair shafts. This information will be correlated to the biologic and chemical/structural information about hair and scalp health. Approximately 50 healthy, Caucasian female subjects will be enrolled in this study. Twenty five participants will be 19-25 years-old and 25 participants 60 years or older. There will be two visits, Baseline and approximately 48 hours after baseline.

Inclusion Criteria:

• Must be willing to sign informed consent
• Female in age groups 19-25 years old and 60 years or older
• Must be of Caucasian descent, to avoid any ethnic differences in hair biology or pigment among different races
• Must be willing to have a thorough scalp and hair shaft examination
• Must be willing to discuss current and past hair care regimens
• Must have washed hair at least 48 hours, but not less than 12 hours prior to study visit
• Must be willing to not wash hair between Baseline and second visit.
• Pregnant and nursing females will not be allowed in the study; a baseline pregnancy test will be done to exclude pregnancy on females of childbearing potential
• Must be >6 months (26 weeks) postpartum
• Must have sufficient contrast between scalp skin color and hair color (Fitzpatrick skin type I-IV)
• Must have hair at least 2 inches long
• May have mild itching and mild scaling of the scalp, but not dandruff
• Must be willing to have hair clipped and shaved to 1 mm within an approximately 1cm2 test site
• Must be a non-smoker for the past 6 months
• Must be in good stable general health, with no current infections
• Must be able to return to the study site 48 hours after the Baseline visit for the second visit.

Exclusion Criteria:

• Must not have hypertension, diabetes, or any neurological disease since all these can affect scalp blood flow
• Must not take any antihistamines for two weeks prior to the baseline visit and throughout the study.
• Must not have any known allergy or past history of anaphylaxis to histamine
• May not have sewn-in or glued hair pieces or extensions at the time of the study
• Must not cut hair during the study
• Must not have hair loss beyond what is considered normal in the opinion of the Investigator at the time of the study
• Must not color hair or have other salon-type procedures (relaxer, permanent, highlighting, etc.) performed within 2 weeks of the initial visit
• Must not have any other underlying scalp disorder that could interfere with the test procedures or findings
• Must not have lost ≥10% of body weight within the past 12 months
• Must not have been on a weight reduction program overseen by a physician or nutritionist within the past 12 months
• Has used hair growth products e.g. minoxidil in the past 18 months
• Has undergone a hair transplant or scalp reduction surgery
• Has participated in a hair growth study within the past 15 months
• Is currently participating in another clinical study at this or any other facility
• Is taking, for a chronic condition, any prescription or over the counter medication(s) that in the opinion of the Investigator are likely to affect the hair properties (e.g. immunosuppressive agents, corticosteroids, or chronic use of anti-inflammatory medication)
• Application of any over-the-counter or prescription drug to the scalp on a routine basis within the past 3 months including but not limited to retinoids (e.g. retinal, tretinoin, retinylpalmitate, retinyl acetate, retinyl propionate), topical corticosteroids, benzyl peroxide, or any topical hormone therapy (e.g. Eterna 27)

Selected from the Wake Forest University Health Sciences Dermatology clinics and responders to Institutional Review Board (IRB) approved advertising