In this study, the investigator will try to highlight the presence of carbonyl compounds in the hair follicles of women with telogen effluvium (ET) linked to stress of various origins (fatigue, infectious diseases, emotional stress ...).

At the cutaneous level, oxidative stress induces the formation of carbonyl compounds which, by binding to proteins, produce nonfunctional adducts inducing cutaneous aging. Is this mechanism, called "Carbonyl stress", also present in the scalp and can it be one of the mechanisms involved in the occurrence of reactive hair loss ? To demonstrate this, samples of hair follicles are made. The proteins are extracted from the samples and then assayed. The oxidized (carbonyl) proteins are labeled with specific fluorescent probes.

Inclusion Criteria:

Criteria related to the Population :

• Women aged from 18 to 40 ans (included)
• Phototype I à IV included, according to Fitzpatrick Classification
• Hair length 5 cm on the sampling area (centro-parietal part)
• Last shampoo at least 2 days before the inclusion visit, without application of styling product, care or water between this last shampoo and the inclusion
• Informed consent signature

Criteria related to the studied condition:

• ET group: hair loss related to various etiologies evaluated by a questionnaire according to the investigator's opinion and positive pull test (at least 3 hair collected per lock of 50 to 60 hair) AND
• Control group : no hair loss, evaluated by the questionnaire and negative pull test (less than 3 hair collected per lock of 50 to 60 hair)

Exclusion Criteria:

Criteria related to Population :

• Menopause
• Pregnancy, breastfeeding, childbirth for less than 6 months

Criteria related to Pathology :

For both groups:

• Alopecia causing hair loss on the upper part of the scalp
• Dermatological pathology or evolving cutaneous lesion in the scalp
• Control group only:
• Chronic unstabilized condition
• Acute evolving pathology

Criteria related to theTreatments :

For both groups:

• Use for at least 1 month of Minoxidil, Aminexil in the 3 months before inclusion or ongoing
• Systemic treatment affecting hair growth
• Any treatment or dietary supplement for antioxidant or capillary

Control group only:

• Treatment of general thyroid disorders initiated or modified for less than 3 months prior to inclusion
• Treatment of anemia if started less than 3 months before inclusion
• General treatment initiated or modified for less than 3 months prior to inclusion in the study

women

Proof of concept study, with confidential data

Monocentric, Exploratory study, open, comparative, in parallel groups