As Spring brings us longer sunnier days, our exposure to UV rays is slowly increasing and the risk of hyper pigmentation (brown spots) rises. Many of my clients find Winter to be an appropriate time to treat hyper pigmentation as exposure to UV is minimal. While this approach can be effective, it's extremely important that we look forward to some preventative measures to ensure the recurrence of hyper pigmentation year round.
How is hyper pigmentation formed? A simplified explanation...
There are many factors involved in why your skin turns dark (UV rays, hormones, medications, injury, genetic makeup) but here in New Zealand the main culprit for uneven skin tone is UV radiation. The cell responsible for your skin turning dark is called your melanocyte.
The melanocyte sits deeper down in your first layer of skin (epidermis) in the bottom layer know as your stratum basale. The melanocytes main role is protection against DNA mutation to your cells from UV rays. Melanocytes produce melanin - a protective pigment in the skin to prevent against skin cancer. Melanocytes "inject" melanin upwards into your skin cells, and is presented as discolouration on the stratum corneum (top layer of skin).
When UV rays penetrate the skin a process occurs where the enzyme tyrosinase (which sits alongside melanocytes) converts the amino acid tyrosine to oxidize and create the melanin to be transported. Over many years of UV exposure our cells become damaged, and tyrosinase has the ability to misfire which essentially leads to the overproduction of pigment = hyper pigmentation.
Very long story short - if you inhibit the enzymatic activity by tyrosinase with topical solutions you can brighten existing lesions, and prevent hyper pigmentation.
It goes without saying that a broad spectrum SPF used daily (yes, even in winter!) is one way to prevent skin discolouration and skin cancer. SPF alone however, is not considered to by a tyrosinase inhibitor. Specific cosmeceutical preparations can help to lighten and brighten existing hyper pigmentation, as well as prevent further dark spots.
All skins can benefit from a tyrosinase inhibitor, especially those with darker skin tones with the ability to tan. Even if you have pale, clear and unblemished skin - prevention will always be better than the cure.
*L-Ascorbic Acid (Vitamin C) - A powerful antioxidant. Tyrosinase requires an oxidizing atmosphere to work, hence why using an antioxidant such as L-Ascorbic acid is very effective. L-Ascorbic acid also lightens existing hyper pigmentation.
*Licorice extract - It's main active ingredient is "glabridin" which has shown to offer 50% inhibition of tyrosinase activity. Also brightens skin tone.
*Retinoids (Vitamin A) - inhibits tyrosinase induction and accelerates cell turnover, leading to loss of pigment
*Alpha Hydroxy Acids (AHA's) - accelerates cell turnover, inhibits melanin formation in melanocytes and enhances penetration of other tyrosinase inhibitors.
Products containing these ingredients are usually in a serum form for optimum penetration, and applied on a daily basis under moisturiser/SPF. In higher percentages they may be used in clinical treatments as part of a series.
In conclusion. While we have great success at treating hyper pigmentation with various modalities, if we prevent the formation of dark spots with topical preparations then long term results will be more easily maintained.
Draelos, Z.D. (2005). Procedures in Cosmetic Dermatology - Cosmeceuticals. Philadelphia, USA: Elsevier Saunders.
Barrett-Hill, F. (2004). Advanced Skin Analysis. Auckland, NZ: Virtual Beauty Corporation.