The Effect of 16-week Dietary Intake of Food Supplements Containing Collagen and MSM on Facial Erythema and Other Skin Parameters

Inclusion criteria: * Caucasian female volunteers aged 35 to 65 years at the time of signing the Informed Consent Form (ICF). * Signed Informed Consent Form (ICF). * Fitzpatrick skin phototypes I-IV. * Presence of visible signs of skin ageing. * Presence of visible facial telangiectasias, primarily on the cheeks. * Presence of facial erythema with a baseline score ≤ 3 on the 5-point Clinical Erythema Assessment (CEA) scale. * Stable erythema-prone facial skin for at least 3 months prior to study inclusion, without clinical signs of active rosacea. * In good general health, as determined by medical history. * Body Mass Index (BMI) \< 35. * Willingness and ability to: * Comply with all study procedures and complete a subject diary. * Maintain usual lifestyle habits throughout the study. * Not initiate or modify oestrogen or progesterone therapies during the study. * Maintain the same cosmetic and skincare routine and comply with sun protection guidelines throughout the study. * Avoid rejuvenation treatments during the study. * Refrain from consuming food supplements containing collagen or other protein-based supplements, methylsulfonylmethane (MSM), or anti-inflammatory and/or antioxidant compounds with a known or potential impact on skin inflammation or vascular response for the duration of the study. Exclusion criteria: * Pregnancy or breastfeeding. * Vegan diet. * Heavy smoking or frequent alcohol-induced flushing. * Occupational or hobby-related excessive heat exposure (e.g. chefs, sauna workers) likely to interfere with vascular stability. * Anticipated sunbathing or solarium use, or major planned changes in sun exposure before or during the study. * Planned major changes during the study in: * Skincare routine * Hormonal therapy (contraception or hormone replacement therapy) * Significant changes in dietary habits or dietary supplementation within 3 months prior to inclusion. * Regular use within 3 months prior to inclusion of food supplements containing: * Methylsulfonylmethane (MSM); * Collagen or other protein-based supplements; * Anti-inflammatory supplements (e.g. bioflavonoids/rutin, curcumin, EPA) and/or antioxidant supplements with a known or potential impact on skin inflammation or vascular response. * Any diagnosed, uncontrolled, untreated, or unstable medical condition. * Clinically significant history of metabolic, gastrointestinal, hepatic, renal, or haematological disease. * Mental incapacity or psychiatric condition that may impair understanding of the study or compliance with study requirements. * Any clinically significant acute or chronic inflammatory skin disease, including but not limited to acne, perioral dermatitis, psoriasis, atopic dermatitis, or lupus. * Skin pigmentation disorders at the assessment sites. * Active rosacea within 3 months prior to study entry, defined as the presence of papules/pustules, frequent flushing episodes typical of rosacea, or ocular involvement. * Frequent vasomotor hot flushes (e.g. perimenopausal or menopausal), which may interfere with erythema assessments. * Use of medications affecting skin or vascular reactivity, including but not limited to: systemic corticosteroids, anticoagulants (e.g. coumarins, heparin), vasodilators (e.g. hydralazine, nitroglycerin), antibiotics with potential to affect erythema or vascular response, immunomodulators, regular or long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) * Use of systemic retinoids within 3 months prior to study entry. * Changes of skin care routine regimen within 4 weeks prior to study entry. * Use of highly concentrated topical products (\>15% azelaic acid, 10% vitamin C…) affecting inflammatory or vascular facial responses within 4 weeks prior to study entry. * Invasive rejuvenation treatments (e.g. medium or deep chemical peels, ablative or vascular laser therapies) within 6 months prior to study entry. * Non-invasive or minimally invasive rejuvenation treatments (e.g. microneedling, mesotherapy, superficial chemical peels, radiofrequency, electrotherapy, ultrasound, IPL) within 3 months prior to study entry. * Known or suspected allergy to any ingredient of the investigational product(s).