The aim of the study is to compare the effects of multiple-dose 16 weeks daily dietary supplementation with 5 g or 3 g of collagen in combination with 1 g or 1.5 g of MSM and 80 mg vitamin C (see 1.2. Investigational and placebo product profile) on skin in healthy human subjects in comparison to placebo product. The main objective is to show that test products have beneficial effects on dermis density, and also on other skin parameters and to investigate differences in the effects among test products.

Single centre, randomized, double-blind, placebo-controlled, one-period effectiveness study will include 135 subjects. Subjects will be divided in five groups, 27 in each. Test group 1 (IP1 group) will receive investigational product 1 (IP1, daily dose 25 mL: collagen 5 g, MSM: 1,0 g, vitamin C: 80 mg), test group 2 (IP2 group) will receive investigational product 2 (IP2, daily dose 25 mL: collagen 3 g, MSM: 1,5 g, vitamin C: 80 mg), test group 3 (IP3 group) will receive investigational product 3 (IP3, daily dose 25 mL: collagen 3 g, MSM: 1,0 g, vitamin C: 80 mg), test group 4 (IP4 group will receive investigational product 4 (IP4, daily dose 25 mL: collagen 3 g, vitamin C: 80 mg) and the placebo group will receive placebo product without those active ingredients (25 mL: 0 g collagen, 0 g MSM). Participants will test continuous administration of placebo or investigational products for 16 weeks to demonstrate and assess multiple-dose effects.

Inclusion criteria:

• Caucasian female volunteers aged between 40 and 65 years at the time of the signature of Informed consent form (ICF),
• Signed Informed consent form (ICF),
• Fitzpatrick skin phototypes I-IV,
• Signs of skin aging,
• In good general health condition,
• BMI < 35
• Willingness to avoid a consumption of any food supplements containing methylsulfonylmethane (MSM), antioxidants, collagen and other protein-based food supplements during the study,
• Willingness to follow all study procedures and keeping a diary during the study (to follow their compliance and palatability).
• Willingness to maintain their living habits and to not begin or change any oestrogen or progesterone therapies,
• Willingness to avoid shaving/depilation of their arms during the study,
• Willingness not to change cosmetic treatment routine during the study,
• Willingness to avoid rejuvenation treatments during the study.

Exclusion criteria:

• Pregnancy or breastfeeding,
• Known or suspected allergy to any ingredient of the tested products,
• Changes in dietary habits and dietary supplementation in the last three months prior to inclusion,
• Regular use of food supplements containing MSM, antioxidants, collagen or other protein-based food supplements in the last three months prior to inclusion,
• Veganism,
• Changes in cosmetic facial and body care routine in the last month prior to inclusion,
• Diagnosed and uncontrolled/untreated/unregulated disease,
• Any clinically significant history of serious metabolic disease, digestive tract disease, liver disease, kidney disease, haematological disease,
• Intake of drugs with any impact on skin reactions (e.g., glucocorticoids, antihistamines, and immunomodulators),
• Any clinically significant acute or chronic skin diseases,
• Skin pigmentation disorders on measuring sites,
• Anticipated sunbathing or solarium visits before or during the study,
• Invasive rejuvenation treatments (e.g. needle rollers, needle mesotherapy, deep/medium-deep chemical peels, laser therapy etc.) in the last 4 months prior to study entry,
• Non-invasive rejuvenation treatments (e.g. radiofrequency, electrotherapy, ultrasound, IPL therapy) in the last month prior to study entry,
• Shaving/depilation of the arms in the last 14 days before inclusion,
• Mental incapacity that precludes adequate understanding or cooperation.