The goal of this observational study is to evaluate the effect of age on skin microbiome.

Inclusion Criteria:

1. Healthy subject;
2. Sex: female
3. Age: 50% having between 25 to 35 years old or 50% between 55 to 65 years old
4. Type: Caucasian
5. Phototype: I to III on the Fitzpatrick scale
6. Subject, having given freely and expressly her informed consent.
7. Subject, psychologically able to understand the study related information and to give a written informed consent;
8. Subject able to comply with protocol requirements;
9. Female of childbearing potential should use a medically accepted contraceptive regimen since at least 12 weeks before the beginning of the study and during all the study.
10. Women between 55 to 65 years old should be menopausal (last menstrual period at least 12 months before the screening visit

Exclusion Criteria:

1. Pregnant or nursing woman or planning a pregnancy during the study;

2. Subject who had been deprived of their freedom by administrative or legal decision or who is under guardianship;

3. Subject who is under guardianship or who is not able to express her consent;

4. Subject in a social or sanitary establishment;

5. Subject suspected to be non-compliant according to the investigator's judgment;

6. Subject having received 6000 euros indemnities for participation in a clinical research in the 12 previous months, including participation in the present study;

7. Subject enrolled in another clinical trial or which exclusion period is not over.

8. Subject with a condition or receiving a medication which, in the investigator's judgment, put the subject at undue risk or which may interfere with the evaluation;

9. Subject suffering from a severe or progressive disease.

10. Subject with current cutaneous inflammatory or infectious processes (eg, acne, herpes), abscess, an unhealed wound, or a cancerous or precancerous lesion on the face that could interfere with the evaluation.

11. Subject with a tattoo, a scar, moles, acne, too many hairs or anything on the studied zones which might interfere with the evaluation.

12. Subject having received injection on the face with botulinum toxin in the year before the screening.

13. Subject having received injection of filling product on the face in the year before the screening visit.

14. Subject having received injection of mesotherapy in the face in the past 6 months before the screening visit.

15. Subject having done a superficial or medium peeling or a superficial scrub on the face within the 2 previous months.

16. Subject having received tensor threads on the face in the two years before the screening visit.

17. Subject having received treatment with a laser, ultrasound or radiofrequency treatment, a dermabrasion, a surgery, a chemical peeling or any other procedure based on active dermal response on the face within the past 6 months.

18. Subject having used LED mask in the three weeks before screening visit

19. Subject undergoing a topical treatment on the face or a systemic treatment:

    • anti-inflammatory medication and/or anti-histamines during the previous 2 weeks and during the study;
    • corticosteroids during the 2 previous weeks and during the study;
    • retinoids, anti-acne treatment and/or immunosuppressors during the 3 previous months and during the study;
    • any medication stabilized for less than one month.

20. Subject having started or changed her oral contraceptive treatment during the three previous months.

21. Subject under oral hormonal substitutive treatment during the year previous the screening visit

22. Intensive exposure to sunlight or UV-rays within the previous month and/or foreseen during the study;

23. Subject having changed her life habits within the previous month and/or during the study;

24. Subject with an excessive consumption of alcohol (more than 2 glasses of wine per day) and/or tobacco (more than 10 cigarettes per day).

25. Subject having started or changed her face care products and or make-up within the previous month

The population to be studied will be women between 25 to 35 years old and between 55 to 65 years old in order to evaluate the relationship between skin collection and saliva sampling and skin measurements.