Antioxidants are indispensable in protecting the skin from oxidative stress caused by environmental factors such as ultraviolet (UV) radiation, pollution, and lifestyle-related influences. This review examines the essential role of antioxidants in modern cosmetology, highlighting their dual functionality as protective agents and active components in skincare formulations. Oxidative stress, primarily driven by an imbalance between reactive oxygen species (ROS) production and the skin’s defense mechanisms, accelerates aging processes, damages cellular structures, and compromises skin integrity. Antioxidants, whether natural or synthetic, act by neutralizing ROS, reducing inflammation, and promoting cellular repair, effectively mitigating these harmful effects. This comprehensive analysis synthesizes findings from 280 studies accessed via key databases, including PubMed, Scopus, and ScienceDirect. It investigates the biochemical mechanisms of antioxidant activity, emphasizing compounds such as vitamins (C, E, A), carotenoids, polyphenols, peptides, and minerals, alongside bioactive extracts derived from algae, fungi, lichens, and plants. Carotenoids, including ꞵ-carotene, lutein, lycopene, and astaxanthin, demonstrate potent antioxidant activity, making them crucial for photoprotection and anti-aging. Phenolic compounds, such as ferulic acid, resveratrol, hesperidin, and xanthohumol, play a significant role in neutralizing oxidative stress and improving skin health. This review also highlights bioactives from algae, fungi, and lichens. Algae, particularly microalgae like Haematococcus pluvialis, known for astaxanthin production, are highlighted for their extraordinary photoprotective and anti-aging properties. Brown algae (Fucus vesiculosus) and red algae (Porphyra) provide polysaccharides and bioactive molecules that enhance hydration and barrier function. Fungi contribute a wealth of antioxidant and anti-inflammatory compounds, including polysaccharides, ꞵ-glucans, and enzymes, which support cellular repair and protect against oxidative damage. Lichens, through unique phenolic metabolites, offer potent free-radical-scavenging properties and serve as effective ingredients in formulations targeting environmental stress. Plant-derived antioxidants offer a diverse range of benefits. Plant-derived antioxidants, such as flavonoids, phenolic acids, and carotenoids, further amplify skin resilience, hydration, and repair mechanisms, aligning with the growing demand for nature-inspired solutions in cosmetics. The integration of these diverse natural sources into cosmetic formulations reflects the industry’s commitment to sustainability, innovation, and efficacy. By harnessing the synergistic potential of bioactives from algae, fungi, lichens, and plants, modern cosmetology is advancing toward multifunctional, health-conscious, and eco-friendly products. Future research directions include optimizing delivery systems for these bioactives, enhancing their stability and bioavailability, and expanding their applications to meet evolving dermatological challenges.
The human body is constantly exposed to harmful environmental factors such as ultraviolet (UV) radiation, air pollution, ozone, cigarette smoke, heavy metals, and lifestyle-related stressors. Photoaging results from the cumulative impact of these stressors, which induce oxidative stress and accelerate degenerative changes in skin cells, leading to premature aging. Oxidative stress, characterized by an imbalance between the generation of reactive oxygen species (ROS) and the body’s ability to neutralize them with antioxidants, further accelerates these degenerative changes. The growing understanding of oxidative stress’s role in skin health has fueled interest in cosmetic formulations enriched with antioxidant compounds. As the field of cosmetology advances, the demand for ingredients with antioxidative properties derived from natural sources is increasing. These naturally occurring compounds are valued for their ability to neutralize ROS, thereby protecting the skin from oxidative damage. In an era of widespread environmental pollution driven by industrial expansion and urbanization, consumers increasingly prioritize natural solutions in both nutrition and skincare. Mitigating these harmful effects can be achieved through a diet rich in antioxidants, carefully selected antioxidant skincare regimens, or targeted supplementation. Cosmetology focuses on maintaining and enhancing the external appearance of the human body, including the skin, hair, and nails. This involves the use of cosmetics, skincare treatments, and customer education on proper hygiene and nutrition. Many plant-based compounds with potent antioxidant properties have been utilized in medicine and cosmetology for decades, while others have been identified only recently through ongoing research. These compounds are not only essential in preventing photoaging but also contribute to managing inflammation, enhancing hydration, and improving overall skin resilience. The exploration and application of these bioactive substances represent a significant focus in the pursuit of innovative, nature-inspired skincare and therapeutic solutions.
The history of antioxidants dates back to antiquity, with evidence suggesting that ancient civilizations, such as the Egyptians, possessed advanced technical knowledge of preservation. They used plant extracts rich in phenolic compounds for embalming, demonstrating an early understanding of oxidative processes. The scientific exploration of oxidation and reduction reactions began in the late 19th century, notably with the observation of rubber oxidation in the 1870s. By the 1940s, the mechanisms of free radical autoxidation were elucidated, leading to the identification of several chain-breaking antioxidants. By the late 1950s, research established a link between oxidative reactions, aging, and the progression of various diseases, leading to the hypothesis that antioxidants could mitigate these processes and potentially extend lifespan.
This period marked the first in vivo experiments in which antioxidants were administered to rodents, providing statistically significant evidence of lifespan extension. Consequently, extensive research efforts were undertaken to explore the sources, biological effects, and potential toxicity of antioxidants, resulting in a vast body of scientific literature—now exceeding 150,000 publications on the topic. The longstanding use of plants for nutritional and medicinal purposes is, in part, attributed to the biological activity of their secondary metabolites, many of which exhibit antioxidant properties. Key compounds such as phenolics, vitamins C and E, and carotenoids contribute to these beneficial effects, underscoring the fundamental role of natural antioxidants in health and disease prevention.
The figure below illustrates the effects of antioxidants on the skin, including benefits such as reducing wrinkles, enhancing skin radiance, evening out skin tone, increasing firmness, stimulating regenerative processes, protecting against harmful radiation, boosting collagen synthesis, and preventing hyperpigmentation.
A comprehensive literature review was conducted utilizing key databases, including PubMed, Google Scholar, Scopus, and ScienceDirect, as well as the recent literature. A total of 280 notable research articles were examined, with no restrictions on publication date.
Antioxidants are bioactive compounds that mitigate or delay oxidative damage to cellular structures induced by free radicals—highly reactive molecules produced through exposure to external factors such as tobacco smoke, ultraviolet (UV) radiation, and environmental pollutants. By stabilizing free radicals and reducing oxidative stress, antioxidants play a pivotal role in safeguarding the body against pathologies such as cardiovascular diseases, malignancies, and neurodegenerative disorders.
Reactive oxygen species (ROS), commonly referred to as free radicals, are highly reactive molecular entities that play a dual role in biological processes, contributing to both physiological and pathological states. Oxidative stress arises when there is an imbalance between ROS production and the body’s antioxidant defense systems’ ability to neutralize them effectively.
By definition, ROS are molecular species capable of independent existence that contain an unpaired electron, a characteristic that confers high reactivity and enables them to donate or accept electrons, thereby acting as oxidizing or reducing agents. Free radicals can carry a positive, negative, or neutral charge. For example, a neutral radical, such as nitric oxide (NO•), retains its unpaired electron without altering the charge of its parent molecule. A positively charged radical forms upon electron loss, while a negatively charged radical results from electron acquisition. These electron transfer mechanisms underpin redox reactions, wherein the electron-donating species undergoes oxidation and the electron-accepting species undergoes reduction.
Although oxygen radicals are the most widely studied, other types of radicals also exist, including those based on carbon (C), nitrogen (N), and sulfur (S). Among the oxygen-containing free radicals most implicated in pathological conditions are the hydroxyl radical (•OH), superoxide anion radical (O 2•−), hydrogen peroxide (H 2 O 2), singlet oxygen (1 O 2), hypochlorite (ClO−), nitric oxide radical (NO•), and peroxynitrite (ONOO−). These ROS are highly reactive and can damage critical biomolecules, including DNA, proteins, lipids, and carbohydrates, within cellular nuclei and membranes. Their activity leads to cellular dysfunction, the disruption of homeostasis, and tissue damage, which are central to the pathogenesis of numerous diseases.
In a well-functioning organism, a homeostatic balance exists between the generation of reactive oxygen species (ROS) and the activity of antioxidant defense mechanisms. Excessive ROS production leads to oxidative stress, which disrupts cellular metabolism. Oxygen homeostasis within the body can be disturbed by both intracellular sources of ROS, such as immune system responses and redox processes within the mitochondrial respiratory chain, as well as extracellular factors.
Lifestyle choices—including diet, alcohol consumption, stimulant use, excessive physical exertion, psychological stress, and prior viral or bacterial infections—significantly impact the efficiency of the body’s antioxidant defense mechanisms.
Oxidative stress is defined as an imbalance between the rate of ROS production and the capacity of the antioxidant defense systems to neutralize them. This imbalance is often implicated in the pathogenesis of various diseases, particularly those associated with chronic and carcinogenic effects of free radicals. The toxic byproducts of oxidative reactions can damage cellular membranes and induce cell death through apoptosis or necrosis.
The cellular redox balance is maintained by a range of antioxidant enzymes, including catalase, superoxide dismutase, and glutathione S-transferase, as well as non-enzymatic compounds such as vitamins A, C, and E and glutathione. These molecules facilitate the detoxification of excess ROS, thereby protecting cells from oxidative damage.
It is hypothesized that free radicals and other reactive oxidants, which are metabolic byproducts whose production increases with aging, are primarily responsible for cellular degradation during the aging process. The destructive effects of reactive oxygen species (ROS) may also manifest in the accumulation of oxidatively modified cellular components within the aging organism. This accumulation is
