Why do I need to exfoliate?
Your skin cells are constantly renewing themselves - your entire
epidermis (outer skin layers) is replaced every 50 days. Millions of dead skin cells
are shed each day from the topmost layer (the stratum corneum) in a natural process called desquamation.
However, many things can interfere with this process, such as ageing, hormonal fluctuations, dietary deficiencies and environmental changes - this can then lead to acne, clogged pores, rough patches, wrinkles, ingrown hairs, and dull, uneven skin. Helping the process along by exfoliating can restore clear, smooth, soft skin.
What exfoliants are available?
Exfoliants can be divided into two types: physical and chemical. Many exfoliants can be bought from the supermarket or department store; additionally, stronger exfoliating treatments can be performed by beauticians and dermatologists.
Physical or mechanical
Anything that is hard and basically scrapes dead skin off: polystyrene beads, plastic grains, crushed apricot kernels, rice bran, oatmeal, facecloths, loofahs, body brushs, razors, face brushes, even clothing. Microdermabrasion is an example of a physical exfoliation technique which can only be performed by a trained professional.
Many scrubs available on the market can be too coarse to be used on most people's faces and end up causing more harm than good - Apricot Scrub is an example. Rounded synthetic beads are a much safer option - however, it's possible that they end up disrupting marine life since polyethylene is generally not biodegradable and beads found in scrubs are too small to be filtered out, but only a very small amount is used. Scrubbing particles which are both environmentally friendly and skin-safe can be found in your kitchen - sugar, salt or baking soda (if your skin is resilient enough).
Scrubs are generally not recommended as the main exfoliating treatment for people with sensitive or irritated skin, and it's very easy to overexfoliate with physical exfoliants simply by scrubbing too hard or too long.
Usually a liquid, doesn't require rubbing to work, contains chemicals which dissolve the "mortar" between the cellular "bricks" and encourage dead skin to lift off. They also sometimes break down the individual dead skin cells. The milder formulations often work best if left on, rather than used in scrubs or cleansers.
AHAs - lactic acid (mild), glycolic acid. Exfoliates surface of skin, may increase turnover/production of new cells. Good for dry and sun damaged skin, since they also have a humectant action.
BHAs - salicylic acid, very similar to AHAs but dissolves oily sebum plugs well, particularly good for acne-prone skin. Also has anti-inflammatory and antibacterial properties
Read more about the differences between AHAs and BHAs here.
Enzymes - certain enzymes have exfoliating properties, including papain (from papaya), bromelain (from pineapple) and keratinase (from bacteria). These have not been the subject of as much research.
Chemical peels - very strong chemicals peels are available from trained professionals. These may give excellent results, but also require recovery time; however, exfoliation is usually not the main desired effect. Some examples are TCA and phenol peels.
How often should I exfoliate?
Exfoliation is great, but it's possible to exfoliate too much! It's different for each person with each different product, so some experimentation is needed - if you overdo it, your skin will let you know, but usually not right away. One of the more common ways people tend to overexfoliate is by using a variety of products at once, then waking up the next day with a red, flaky and itchy face! Some dryness and irritation is common post-exfoliation - make sure you moisturise.
Some medications (e.g. acne medications) make your skin more prone to irritation, so it's important to be cautious when starting a new exfoliating treatment. This goes for anything else that gives you irritated skin, like shaving or sunburn - you don't want to exacerbate the damage!