The Impact of Probiotics on Skin Hydration in Youth with Mild Acne

Inclusion Criteria:

1. Age between 15 and 26 years (limits included),

2. Suffering from mild acne vulgaris for at least 1 year (GEA score 1 or 2),

3. For women (adolescents and adults) who have started their sexual life: bemenstruated and with the same reliable contraception method since at least sixmonths before the beginning of the study and agreeing to keep it during the entireduration of the study. Following contraception methods are allowed: hormonalcontraception, intra uterine device, surgical intervention, condoms withspermicides. Contraceptive implants (e.g. Nexplanon®) are not allowed. For women whohave not started their sexual life yet, who do not intend to start their sexuallife, who do not use a contraception: be menstruated and keep the habits unchanged;

4. For women (adolescents and adults): negative urine pregnancy test result;

5. Good general and mental health within the opinion of the investigator: no clinicallysignificant and relevant abnormalities of medical history or physical examination;

6. Agree to maintain the same skin care regimen throughout the study;

7. Able and willing to participate in the study by complying with the protocolprocedures, as evidenced by their dated and signed informed consent form. Foradolescents (15-17 years): informed consent form signed by the guardians/parents andthe individual willing to participate;

8. Affiliated with a social security scheme. For adolescents: affiliated with thesocial security scheme of the guardians/parents;

9. Agreeing to be registered on the national file of volunteers in biomedical researchfile.

After 1 month following to the non-inclusion of the participant for failure to comply with one or more of the inclusion criteria listed above, a re-screening could be performed.

Exclusion Criteria:

1. GEA score <1 or > 2 (corresponding to the absence of acne or a moderate, severe orvery severe acne vulgaris),

2. Any disease that affects the secretion of sex hormones,

3. Any other dermatological disease (psoriasis, atopic dermatitis, allergy, eczema,etc.);

4. Suffering from a metabolic disorder (diabetes, uncontrolled thyroidal condition,uncontrolled arterial hypertension, etc.) and/or from severe chronic disease (cancer, renal failure, HIV, immunodeficiency, hepatic or biliary disorders,arthritis, uncontrolled cardiac disease, etc.) or from a disease found to beinconsistent with the conduct of the study by the investigator;

5. Immunodeficiency (immunodeficient and immunocompromised participants, e.g. cancer,HIV, lymphoma, participants on long-term corticosteroid treatment, chemotherapy, andallograft participants);

6. Positive COVID-test results within the last 2 weeks and/or currently showingsymptoms of COVID-19;

7. Use of any systemic antibiotic or oral zinc treatment within 4 weeks prior torandomization, or isotretinoin within 3 months prior to randomization.

8. Regular consumption of probiotics, fiber supplements, fermented milk, and/or yogurtcontaining probiotics within 2 weeks prior to randomization and agreeing not toconsume this type of product during the whole study;

9. Use of hormone replacement therapy (including oral contraceptives) for less than 6months;

10. Under treatment or dietary supplement which could significantly affect skinmicrobiota according to the investigator or stopped in a too short period before V1;

11. Use of topically applied products (including topical acne drug) that could modulatepotential skin improvement within 4 weeks prior to randomization. This includesproducts with a pH ≥ 8 such as hormone treatments, retinoid and other skin cleansingproducts, Micellar waters pH ≤ 5 can be used without rubbing the skin too hard witha cotton wool pad in order not to induce a Köbner phenomenon (appearance of new acnelesions on healthy but traumatised skin);

12. UVA or UVB exposure in the last 4 weeks or expected exposure during the study (shortdaily sun exposure is acceptable). The use of a UVA and UVB protection sunscreenfactor 50 is mandatory during the study to protect against UVs;

13. With a known or suspected food allergy or intolerance or hypersensitivity toingredient of the study products (yeast);

14. Pregnant or lactating women or intending to become pregnant within 3 months ahead;

15. With significant change in dietary or physical activity habits in the 3 monthsbefore randomization and not agreeing to keep them unchanged throughout the study (hyper or hypocaloric diet, planned start or stop of sports activity in the next 3months);

16. With a personal history of anorexia nervosa, bulimia, or significant eatingdisorders within 3 years prior to randomization;

17. Consuming more than 2 standard drinks daily of alcoholic beverages or not willing tomaintain their drinking habits unchanged throughout the study;

18. Participating in another clinical trial or in the exclusion period of a previousclinical trial, or participating in cosmetic tests with or without patch tests orconsumer tests with food supplements containing probiotics;

19. Smoking more than 5 cigarettes per day;

20. For adults (age ≥ 18 years): Under legal protection (guardianship, wardship) ordeprived of his/her rights following an administrative or judicial decision;

21. Presenting psychological or linguistic incapability to sign the informed consent;

22. Impossible to contact in case of emergency;

23. Having received, during the last 12 months, indemnities for clinical trial higher orequal to 4500 Euros.

After 1 month following to the non-inclusion of the participant for failure to comply with one or more of the exclusion criteria listed above, a re-screening could be performed.