Antioxidants are molecules capable of neutralizing free radicals, unstable substances generated by environmental aggressors such as UV radiation, pollution, and lifestyle factors, which can damage cells, proteins, and DNA.

In the skin, oxidative stress accelerates photoaging, a process characterized by the appearance of wrinkles, spots, loss of elasticity, and uneven tone, primarily induced by chronic exposure to ultraviolet radiation.

Melanin is the pigment produced by melanocytes that determines skin color and serves a protective function against UV radiation. It is formed through melanogenesis, an enzymatic process regulated by multiple cellular signals.

UV radiation increases the production of reactive oxygen species (ROS), which activate signaling pathways that stimulate melanogenesis. Antioxidants such as glutathione (GSH) and vitamin C help neutralize ROS and can modulate this process; therefore, maintaining an adequate antioxidant balance is key to limiting oxidative stress and excessive hyperpigmentation.

Tanning, the result of increased melanin following exposure to UV radiation, is a natural skin defense mechanism, but it also serves as a marker of skin damage.

Antioxidants can help minimize the oxidative stress induced by UV radiation; however, they do not replace the use of sunscreen, as no single antioxidant has demonstrated photoprotection equivalent to sunscreen filters.

Dietary antioxidants contribute to photoprotection by neutralizing the reactive oxygen species generated by UV exposure, reducing oxidative stress and DNA damage, which can complement traditional photoprotection strategies.

Glutathione is a tripeptide composed of cysteine, glycine, and glutamic acid that is naturally present in cells and plays a central role in antioxidant defense and cellular detoxification processes.

It is frequently called the “master antioxidant” due to its regulatory role within the intracellular antioxidant system.

• Oral: supplements, with evidence suggesting greater bioavailability in reduced or liposomal forms.
• Topical: creams and lotions formulated for dermatological use.

Melanin is the main determinant of skin color, and its production increases after sun exposure.

Some studies suggest that glutathione:

• May reduce melanin production, contributing to a more uniform skin tone in photo-exposed areas.

• May modestly contribute to improving skin elasticity and the appearance of wrinkles in specific clinical contexts, such as in individuals with visible signs of skin aging.

Important:
Although results are promising in certain controlled trials, the available evidence is not yet conclusive. The efficacy of glutathione depends on the form of administration, dosage, and duration of treatment, and its use should be evaluated by a healthcare professional.

Dietary antioxidants play a relevant role in maintaining oxidative balance. Vitamin C, vitamin E, coenzyme Q10, as well as other bioactive compounds, including carotenoids and polyphenols, have been widely studied for their ability to reinforce antioxidant defenses and contribute to photoprotection.

Human intervention studies with diets rich in carotenoids have demonstrated photoprotective effects, requiring treatment periods of at least 10 weeks to observe clinically relevant benefits.

Antioxidants neutralize free radicals before they damage structural skin cells like collagen and elastin. Additionally, some antioxidants activate defense pathways such as Nrf2, strengthening the skin's intrinsic antioxidant capacity.

• Vitamin C: Inhibits tyrosinase in a dose-dependent manner; this is the key enzyme in melanin synthesis. Furthermore, it promotes collagen synthesis and contributes to photoprotection.

• Vitamin E: A fat-soluble antioxidant that acts synergistically with vitamin C to neutralize free radicals, protect cell membrane lipids, and repair skin damage. The combination of both vitamins has been shown to significantly reduce erythema and the number of damaged cells after UV exposure.

• Coenzyme Q10: UVB radiation stimulates the production of matrix metalloproteinases (MMP), enzymes that degrade collagen and elastin. CoQ10 reduces this damage by decreasing free radicals induced by UVB radiation and attenuates the activation of inflammatory mediators such as IL-6, which suggests its usefulness as an adjuvant in the prevention of sun-induced skin aging.

• Polyphenols (green tea, resveratrol): Neutralize free radicals and activate cellular antioxidant defenses through pathways such as Nrf2. In vivo and clinical studies show that they reduce hyperpigmentation and UV-induced sunburn. Furthermore, they inhibit melanogenesis by blocking tyrosinase and the expression of pigmentary genes.

• Carotenoids (β-carotene, lycopene, lutein, etc.): Carotenoids offer protection against ultraviolet radiation-induced skin damage through various mechanisms such as neutralizing reactive oxygen species (ROS) and suppressing UV-induced cellular inflammatory responses. They require prolonged treatment periods (a minimum of 10–12 weeks) to achieve significant photoprotective effects.

1. Daily use of sunscreen as the first line of defense against sun damage and photoaging.
2. Supplements such as glutathione and other antioxidants may offer moderate cosmetic benefits, but they do not replace sun protection.
3. Incorporating topical antioxidants into one's daily routine can help neutralize free radicals and improve skin texture and tone.

Exposure to ultraviolet radiation is one of the main factors responsible for cutaneous oxidative stress and photoaging, manifested by alterations in skin tone, texture, and elasticity.

In this context, photoprotection remains the primary and essential strategy for preserving skin health and preventing sun-induced damage.

Antioxidants play a relevant complementary role by contributing to the neutralization of reactive oxygen species generated by UV radiation, helping to protect key skin structures such as collagen, elastin, and cellular DNA. Both dietary and topical antioxidants can support and contribute to a better skin response against oxidative stress.

Glutathione, due to its central role in regulating redox balance and its interaction with other antioxidant systems, is emerging as a compound of interest in skin care. Available evidence suggests that it can modulate melanogenesis and contribute modestly to the improvement of skin tone and quality; however, its clinical efficacy depends on factors such as the method of administration, dosage, and duration of use, and it still requires further support through high-quality clinical studies.

Therefore, a comprehensive strategy for skin health must prioritize adequate photoprotection and may benefit from the use of antioxidants, such as glutathione, vitamins, and bioactive compounds, as adjuvant tools.

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