Reactive oxygen species or oxygen free radicals exist in our environment and are predominantly generated by air pollution, sunlight (UVA and UVB radiation) and smoking. Oxygen free radicals are molecules where the oxygen atom has an unpaired electron making it unstable. In order for the free radicals to stabilise, they roam around the body searching for an electron to pair up with. These reactions are called oxidation. Due to their reactive nature, free radicals trigger large chain chemical reactions in our bodies that cause oxidative stress, damaging our DNA and other parts of cells.[1] Free radicals can be neutralised by compounds known as antioxidants. Antioxidants bind to free radicals, stabilising them and preventing more oxidation reactions from occurring.  Antioxidants are the agents responsible for keeping the body cells healthy and protected from free radicals. Skin is an external and our largest organ, making it extremely vulnerable to free radicals. When our skin suffers from oxidative stress, it manifests as hyperpigmentation, fine lines, wrinkles and loss of elastin and collagen; leading to prematurely aged skin and in some cases cancer. These consequences can be managed by implementing precautions to keep our skin protected such as applying sunscreen (UVA and UVB SPF) to block UVA and UVB radiation; and incorporating antioxidants in skincare. [2][3] In this article, we will discuss the benefits contributed by antioxidants in skincare. Some of the most widely used antioxidants are vitamin C, vitamin E and carotenoids. These antioxidants are essential nutrients that are predominantly found in plants. In other words, they cannot be synthesised by the human body and must be obtained from external sources. These antioxidants not only protect our skin from oxidative stress by neutralising free radicals but in fact exhibit multiple mechanisms of action on the skin when applied topically.[4]

Vitamin C
L-ascorbic acid aka vitamin C is a potent water-soluble antioxidant that functions in the aqueous compartment of the cell. It effectively neutralises free radicals, providing skin protection and helping maintain healthy skin cells. Vitamin C can also effectively brighten the skin and reduce hyperpigmentation. This is because vitamin C interacts with the copper ions at the tyrosinase active sites, inhibiting tyrosinase enzyme action thereby decreasing melanin production.[5] Oral supplementation of vitamin C can also enhance the health and appearance of the skin. When taken orally, vitamin C improves vasodilation. Our blood vessels in the face and other body parts tend to shrink due to free radical damage. Vitamin C increases the concentration of nitric oxide, which relaxes the blood vessels, causing them to expand because a higher concentration of nitric oxide helps in vasodilation. Vasodilation increases blood flow in the circulatory system and maximises the nutrient delivery to body cells including skin cells.[6] Vitamin C can be found in the following plants:
  • Lemon (Citrus Limon)
  • Aloe Vera (Aloe Barbadensis)
  • Apple (Pyrus Malus)
  • Seaweed (Fucus Vesiculosis)
  • Tomato (Solanum Lycoperiscum)
  • Passionfruit (Passiflora Edulcis)
  • Blueberry (Vaccinium Myrtillus)
  • Grapeseed (Vitis Vinifera)
  • Avocado (Persea Gratissima)
Vitamin E
a-tocopherol aka Vitamin E is a lipid-soluble antioxidant that functions in the lipophilic compartment of cell membranes. Vitamin E effectively mitigates oxidative damage that free radicals cause, providing skin protection and helping maintain healthy skin cells. Vitamin E also boosts hydration of the skin by improving its water-binding capacity. Studies have demonstrated vitamin E exhibiting anti-acne properties. Breakouts and acne can sometimes be caused by the lipid peroxidation of bacterial-induced leakage from sebaceous glands and hair follicles. Vitamin E works to prevent lipid peroxidation, thus preventing inflammation, breakouts and acne. In addition, vitamin E aids in preventing inflammatory damage such as UV-induced swelling and erythema following UV exposure.[7][8] Vitamin E can be found in the following plants:
  • Aloe Vera (Aloe Barbadensis)
  • Seaweed (Fucus Vesiculosis)
  • Tomato (Solanum Lycoperiscum)
  • Avocado (Persea Gratissima)
  • Pomegranate (Punica Granatum)
  • Rose (Rosa Damascena)[9]

Beta carotene
Beta-carotene is converted to retinyl esters by the epidermis and thus acts as a precursor of vitamin A. Beta-carotene, or vitamin A, not only offers potent antioxidant properties preventing oxidative damage from occurring; but it also increases the rate of skin cell turn over, giving the skin a more uniform tone, brighter complexion and encourages healthy skin cell function.[10][11] Beta-carotenoids can be found in the following plants:
  • Carrot (Daucus Carota)
  • Melon (Cucumis Melo)
  • Seaweed (Fucus Vesiculosis)
  • Tomato (Solanum Lycoperiscum)
  • Passionfruit (Passiflora Edulcis)
  • Moringa (Moringa Oleifera)
Antioxidants tend to work more effectively when they are combined with other antioxidants. This is because combining antioxidants together can often lead to synergistic mechanisms of action. The antioxidant effects of beta-carotene, vitamin C and vitamin E are synergistic when combined. Beta-carotene is more lipophilic than vitamin E, which enables it to scavenge radicals within the lipophilic compartment of cell membranes more efficiently than vitamin E. Vitamin E helps preserve the efficacy of vitamin C by preventing it from being oxidized quickly. Together, this trio works effectively to optimise antioxidant activity.[12] Studies have also indicated significant synergistic antioxidant activity when vitamin C was combined with vitamin E and ferulic acid. Ferulic acid improves the chemical stability of vitamin C and E, increasing photoprotection from UV radiation on the skin between fourfold to eightfold.[13] To optimise the protection of your skin from environmental stressors, use a product that contains multiple antioxidants. Our Antioxidant Complex Concentrate Serum contains 24 plant extracts, each comprising of an array of antioxidants working in concert to maximise antioxidant activity on the skin.   DISCLAIMER As a service to our readers, Eliksir aims to provide an objective standpoint in all its articles. Please note the date of the article, as future research may discredit past research. No content on this site, regardless of date, should ever be used as a substitute for direct advice from your dermatologist, doctor or another qualified clinician.   References:
  1. M. McCord, “The evolution of free radicals and oxidative stress”,The American Journal of Medicine 108.8 (2000): 652-659
  2. D. Fox, et al; “Controversies in Sunscreens: A Practical Approach”, The American Journal of Medicine 133.12 (2020): 1378-1379
  3. A. Addor, “Antioxidants in dermatology”, Anais brasileiros de dermatologia92 (2017): 356-362
  4. Herranz-López, María, et al; “Antioxidants and Skin Protection.” (2020): 704.
  5. M. Sanadi, et al; “The effect of Vitamin C on melanin pigmentation–A systematic review.” Journal of Oral and Maxillofacial Pathology: JOMFP24.2 (2020): 374
  6. Mak, et al; “Vitamin C prevents hyperoxia-mediated vasoconstriction and impairment of endothelium-dependent vasodilation.” American Journal of Physiology-Heart and Circulatory Physiology 282.6 (2002): H2414-H2421
  7. A. Keen, et al; “Vitamin E in dermatology.” Indian dermatology online journal7.4 (2016): 311
  8. Wu, et al; “IL-8 production and AP-1 transactivation induced by UVA in human keratinocytes: roles of d-α-tocopherol.” Molecular immunology 45.8 (2008): 2288-2296.
  9. Shintani, et al; “Elevating the vitamin E content of plants through metabolic engineering.” Science 282.5396 (1998): 2098-2100
  10. Antille, et al; “Topical β‐carotene is converted to retinyl esters in human skin ex vivo and mouse skin in vivo.” Experimental Dermatology 13.9 (2004): 558-561
  11. Arct, Jacek, et al; “β-Carotene in skin care.” Pol J Cosmetol 19.3 (2016): 206-21
  12. Niki, Etsuo, et al. “Interaction among vitamin C, vitamin E, and beta-carotene.” The American journal of clinical nutrition 62.6 (1995): 1322S-1326S.
  13. Lin, Fu-Hsiung, et al. “Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin.” Journal of Investigative Dermatology4 (2005): 826-832.