Most of us have been recipients of much indoctrination regarding the benefits of antioxidants, both for our health and our appearance. Eat your multi-colored vegetables, drink your freshly-obtained green juice, take your vitamins, and slather on expensive skin creams loaded with these nebulous molecules, and you will be fit, appear young, beautiful, active and healthy, right? With claims like these, it seemed inevitable that hair care products showcasing these materials would make their debut on the shelves of hair salons, health food stores, and drug stores, and of course, this is the case, especially in the natural market sector.
But are these ingredients truly beneficial when used in topically applied hair care products, or are they simply a clever marketing strategy with minimal effects? A consumer armed with knowledge of what oxidative damage is, how it occurs, and what can be used to protect against it has the advantage when evaluating product claims and making purchases.
What is oxidative damage?
Oxidation is the process whereby a molecule loses an electron and is cleaved into its substituent atoms or groups. Some of these species are left having an unpaired electron in their outer shell, which leaves them in a highly unstable and reactive state, as they are driven to complete their outer shells via pairing all electrons. These are called free radicals or reactive oxygen species (ROS).
In order to complete its outer shell of electrons, the free radical will attack adjacent molecules and abstract an electron from them, generating a new radical which is also unstable and seeks to “steal” an electron from its neighbors. This initiates a chain reaction, which is the basis of many polymerization reactions, but which can also be very destructive to living cells and systems. These free radicals can attack cell lipid layers, DNA, proteins, and many other essential structures, disrupting key biological processes and resulting in aging, decreased function, and pathological processes such as cancer.
Hair is not comprised of living cells, but its keratin-based structures are still susceptible to oxidative damage from a wide variety of sources. This damage leads to split ends, broken hairs, rough cuticles, frizz, tangling, lack of luster, diminished curl retention, and loss of color (natural or artificial). Identification of the many sources of free radical exposure can help a curly to reduce their overall risk of accumulating this type of structural degradation.
Exposure to ultraviolet radiation is one frequent route for oxidative damage, where the sun’s rays penetrate the hair shaft and deplete the natural melanin resident in the cortex and also alter the protein structures of both the cuticle and cortex. Chemical processes, particularly bleaching and permanent dyeing are culprits in the depletion of natural melanin and creating substantial oxidative damage. Additionally, relaxers, perms, keratin treatments, and heat styling contribute to formation of free radicals, which attack both the lipids and the proteins in the cuticle structures. Exposure to ozone, pollutants, tobacco smoke, substances in our water, as well as radiation all add to the continual exposure to free radicals and their damaging processes. Damage is pervasive and cumulative, and damaged hair becomes more porous and even more vulnerable to oxidative damage. For this reason, prevention and minimization are critical to preserve the health and beauty of hair.
- Vitamin E (α-Tocopherol)
- Beta Carotene
- Vitamin C
- Vitamin A
- Plant extracts (green tea, grape seed extract, lemongrass, oolong, kiwi)
- Trace minerals
How Do Antioxidants Work?
We know from advertisements and reports in the media, as well as from more academic sources, that antioxidants are the key to dealing with this constant attack from free radicals, but what exactly is their role in the process? Antioxidants mitigate and prevent damage to cells and structures from free radical and reactive oxygen species by putting the brakes on the chain reaction that destroys everything around it. The mechanism by which they achieve this varies, depending upon the antioxidant, but generally it is accomplished via an electron or hydrogen donor process. These molecules are called free radical scavengers.
One common antioxidant is Vitamin E (α-Tocopherol), which donates an electron to an unstable free radical, rendering it stable, but becoming oxidized itself. However, rather than becoming a participant in the free radical chain reaction, the oxidized version of α-tocopherol is then either excreted or regenerated via reduction (hydrogen donation) by Vitamin C (ascorbic acid).