Antioxidants and Skin: Oxidative Damage, Routine and Clinical Evidence

Cutaneous oxidative damage is the central mechanism behind extrinsic skin ageing: free radicals generated by ultraviolet radiation, air pollution, tobacco smoke and visible light degrade collagen and elastin, reduce extracellular matrix synthesis and accelerate the appearance of wrinkles, hyperpigmentation and loss of radiance. Antioxidants — topical, dietary and oral — work on complementary fronts. This guide reviews the clinical evidence and explains how to build a coherent antioxidant routine.

What oxidative damage is and why it affects the skin

Oxidative stress is an imbalance between the production of reactive oxygen species (ROS) and the capacity of endogenous antioxidant systems to neutralise them. The skin is one of the organs most directly exposed to external ROS generators: ultraviolet radiation (UVA and UVB), visible light (especially blue-violet), air pollution (PM2.5, NOx, ozone), tobacco smoke and, to a lesser extent, infrared radiation.

When ROS overwhelm the skin's antioxidant capacity, three key processes of extrinsic ageing are triggered: (1) enzymatic degradation of collagen and elastin through activation of matrix metalloproteinases (MMP-1, MMP-3, MMP-9); (2) peroxidation of membrane lipids, which impairs the skin barrier; (3) cellular DNA damage and dysregulation of melanocytes, contributing to hyperpigmentation and chronic low-grade inflammation. The visible clinical consequence is what we call photoaging: wrinkles, loss of elasticity, uneven hyperpigmentation, telangiectasias and loss of radiance.

How antioxidants act on the skin

Antioxidants that act on the skin do so through three complementary routes:

• Topical route: creams, serums and cosmetic formulations containing antioxidants (vitamin C, vitamin E, niacinamide, resveratrol, ferulic acid) act directly on the surface layer. Their penetration depends on the vehicle and the formulation.
• Dietary route: the regular intake of fruit, vegetables, nuts, extra virgin olive oil, green tea and spices supplies polyphenols, carotenoids and water- and fat-soluble vitamins that are distributed systemically, including to the skin.
• Oral supplementation route: specific ingredients at standardised doses (carotenoids, hydrolysed collagen, concentrated polyphenols) formulated as a food supplement, with clinical evidence documented across skin markers.

The three routes are complementary, not mutually exclusive. The strongest evidence supports combined interventions (topical + dietary) over isolated oral supplementation. No single antioxidant reverses established skin damage; the rationale for use is preventive and maintenance-oriented.

Ingredients with the strongest evidence for skin

For information: The content of this section is informational in nature and is based on published scientific research. It does not constitute medical advice or individual dermatological recommendation. Skin conditions require specialist medical diagnosis and follow-up. Always consult your dermatologist before starting any treatment or supplementation.

Astaxanthin (oral and topical)

Astaxanthin, a red carotenoid derived from the microalga Haematococcus pluvialis, has been the subject of a growing body of clinical research on skin. A systematic review and meta-analysis published in Nutrients (Zhou X et al. 2021) synthesised the available evidence on astaxanthin and human skin ageing: the studies document improvements in hydration, elasticity and a reduced appearance of wrinkles with oral supplementation, especially when combined with topical application. The size of the effect is modest and depends on the dose and duration of the study. For more detail, see the Astaxanthin fact sheet.

Lutein and zeaxanthin

Although their most studied action is ocular (the retinal macula), the macular carotenoids also accumulate in the skin and contribute to photoprotection. The review by Kumar et al. published in the Journal of the American Nutrition Association synthesised the photoprotective mechanisms of lutein and zeaxanthin in the macula and, by extension, described their role in cutaneous photoprotection. The main dietary source is dark green leafy vegetables. For supplementation, see the Lutein fact sheet.

Lycopene

Lycopene, the red carotenoid predominant in cooked tomatoes, is one of the antioxidants with the most documented clinical evidence for dietary-based cutaneous photoprotection. A systematic review and meta-analysis published in Critical Reviews in Food Science and Nutrition (Zhang X et al. 2024) synthesised the evidence on tomato and lycopene against molecular and clinical markers of UV-induced skin damage. The studies document reductions in UV damage markers with regular consumption of cooked tomato or supplemental lycopene. Lycopene bioavailability improves significantly with cooking and the presence of fat (olive oil). See the Lycopene fact sheet.

Oral hydrolysed collagen

Supplementation with oral hydrolysed collagen peptides has been the subject of several recent meta-analyses. A systematic review and meta-analysis published in Nutrients (Pu SY et al. 2023), which included 26 randomised controlled trials with 1,721 participants, documented significant improvements in skin hydration and elasticity with oral hydrolysed collagen supplementation. An earlier systematic review (de Miranda et al. 2021, International Journal of Dermatology) reached similar conclusions. The minimum duration needed to observe effects in most studies is 8–12 weeks.

It is worth noting that the effect of oral collagen is not due to the direct incorporation of the peptides into the skin, but to the cell signalling these peptides modulate in dermal fibroblasts.

Vitamin C

Topical vitamin C (L-ascorbic acid) is one of the cosmetic antioxidants with the strongest evidence base. It inhibits melanogenesis, neutralises UV-induced ROS, is an essential cofactor in collagen synthesis and modulates metalloproteinase expression. Formulation stability (low pH, opaque packaging) and concentration (10–20%) are critical factors. Oral vitamin C maintains adequate plasma levels, but its isolated cutaneous impact is modest compared with topical application.

Other ingredients with evidence (summary)

• Vitamin E: a fat-soluble membrane antioxidant. Synergy with vitamin C is documented. Topical + oral.
• Niacinamide (vitamin B3): topical. Improves the skin barrier and reduces hyperpigmentation.
• Resveratrol and other polyphenols: topical. Activators of Nrf2 (the factor that switches on the cell's antioxidant defences), with modulation of inflammation.
• Green tea polyphenols (EGCG): topical. Photoprotection documented in small studies.
• Curcumin: oral. Systemic NF-κB modulation (an inflammation signalling pathway) with an indirect impact on cutaneous inflammation. See the Turmeric fact sheet.

Oxidative damage and skin ageing

Skin ageing is clinically divided into two components: intrinsic (genetic, chronological, unavoidable) and extrinsic (environmental, preventable and modifiable). Most of the visible signs of facial ageing are extrinsic in origin (according to various dermatological estimates). Of these factors, UV radiation is the main aggressor (photoaging), followed by air pollution, tobacco smoke and visible light.

Visible and blue-violet light on the skin

Beyond its retinal impact, visible light (including the blue-violet fraction from screens and sunlight) penetrates the dermis and induces hyperpigmentation, especially in phototypes IV–VI. The clinical evidence on the magnitude and reversibility of this effect is still evolving, but current dermatological recommendations include the use of sunscreens with visible-light coverage (tinted) in people with melasma or a tendency to hyperpigmentation.

Air pollution and the skin

Fine particles (PM2.5) and the associated polycyclic aromatic hydrocarbons penetrate the skin barrier, generate ROS through activation of the aryl hydrocarbon receptor (AhR) and are associated with a higher incidence of pigment spots and wrinkles in urban cohorts compared with rural populations. Protective measures include double-phase facial cleansing at the end of the day and regular use of a sunscreen with antioxidant properties.

How to build an effective antioxidant routine

Sunscreen: the non-negotiable foundation

No antioxidant strategy replaces sunscreen. Daily sun protection with SPF 30+ (50 for intense exposure or fair phototypes) is the intervention with the strongest clinical evidence for preventing photoageing. Modern formulations include filters with UVA + UVB + visible-light coverage and often incorporate antioxidants (vitamin E, niacinamide, ectoine).

A basic antioxidant routine

• Morning: gentle cleansing + antioxidant serum (vitamin C 10–20%, optionally + vitamin E + ferulic acid) + moisturiser + SPF 30–50 sunscreen.
• Evening: double cleansing (especially important in polluted urban environments) + an active ingredient suited to your goal (retinoid, niacinamide, peptides) + a repairing moisturiser.
• Daily (dietary route): a Mediterranean diet with an emphasis on fruit and vegetables of varied colours, cooked tomato with olive oil (lycopene), oily fish (omega-3), nuts (vitamin E) and green tea.
• Oral supplementation: when chosen, align it with your goals. Astaxanthin, hydrolysed collagen and combined carotenoids are the options with the strongest evidence base.

Effective combinations

The topical + oral synergy is better documented than isolated oral supplementation. The PLENIAGE® Antiox Pro formula combines eight ingredients featured in antioxidant research: NAC 300 mg, glutathione 120 mg, CoQ10 100 mg, turmeric 100 mg, pomegranate 100 mg, astaxanthin 4 mg, lutein 4 mg and lycopene 6 mg. Each ingredient is backed by its own scientific research; the specific combination in this formula has not been the subject of a dedicated clinical trial.

Safety, contraindications and precautions

• Topical vitamin C: may irritate sensitive skin at high concentrations. Start at 10% and increase gradually.
• Topical retinoids: incompatible with vitamin C in the same routine (alternate morning/evening). Contraindicated during pregnancy and breastfeeding.
• Carotenodermia: prolonged, very high intake of astaxanthin or lycopene can produce a slight orange-yellow tint to the skin, which is completely reversible once intake is reduced.
• Supplements in oncology: people undergoing cancer treatment should consult their oncologist before starting antioxidant supplementation.
• Pregnancy and breastfeeding: concentrated oral extracts (high-bioavailability turmeric, etc.) require medical advice.
• Sunscreen is not optional: no antioxidant strategy (oral or topical) replaces daily sun protection.

This page is part of the Antioxidants and defences cluster. To explore specific ingredients in more depth, see also the fact sheets for Glutathione, Pomegranate and N-acetylcysteine.

Cutaneous oxidative damage is the central mechanism behind visible extrinsic ageing. The most effective strategy combines daily sun protection (non-negotiable), a cosmetic routine with topical antioxidants (vitamin C + vitamin E + ferulic acid), dietary antioxidant density (a Mediterranean diet + cooked tomato with olive oil) and, optionally, targeted oral supplementation (collagen, astaxanthin, carotenoids). No single antioxidant reverses established damage; the rationale is preventive and based on sustained maintenance.

At PLENIAGE® we publish scientific content on evidence-based supplementation. You can explore the Antioxidants and defences cluster for more fact sheets and related articles.