Bleaching products fade areas of unwanted pigmentation by disrupting the production and distribution of melanin in the skin by targeting overactive melanocytes (pigment-producing cells). There are a variety of ways to accomplish this and studies have shown that the best results occur when using a combination of two or more of these ingredients.
Tyrosinase is a copper enzyme that stimulates melanin production in the melanocyte. Most whitening agents fall under this category, as they interfere with the enzyme's function thereby reducing pigment production in the melanocyte.
Hydroquinone (HQ) is a hydroxyphenolic compound that has been widely used for skin lightening for 50 years. It is the only FDA-approved product for skin bleaching on the market, and a prescription is required to obtain products with a concentration above 2%. HQ is the most widely studied bleaching agent available, and its effectiveness is solidly supported through scientific studies, but its use can come at a cost. The product can be very irritating to sensitive skin, and in some cases can even cause pigmentation to darken and get worse, particularly in those with very dark skin types. Long term use of HQ, particularly in higher concentrations of 4% or more, can lead to the development of a permanent condition known as exogenous ochronosis. HQ is also very difficult to stabilize and will oxidize quickly if exposed to light and air. If a product containing HQ has darkened from an off-white or a creamy, pale yellow to a gold or brown color, it is no longer effective and should be discarded. It is best to start using HQ products gradually, every couple of days or so, and build up a tolerance. As the skin adjusts, you can then increase to daily use. PrecisionMD VIVATIA Brightening Complex (2% HQ) matches the performance of 4% HQ in its lightening effect of the skin.
When using hydroquinone, it is imperative to stay out of the sun as much as possible in order for the treatment to work. Exposure to sun deteriorates the HQ and renders it ineffective. Always wear a full-spectrum sunblock, and if you must go outside, be sure to wear a hat. Elta MD UV Clear Broad-Spectrum SPF 46is a lightweight, oil-free and non-comedogenic sunscreen that is easy to use under makeup.
Kojic acid, a by-product of rice fermentation, was first discovered in Japan in 1907. Kojic acid is the second most-common bleaching agent and is a more natural and gentle alternative to the stronger effects of the more frequently used hydroquinone. It penetrates the upper skin layers and inhibits the production of epidermal melanin. Kojic acid does pose the risk of causing allergic or sensitizing reactions in a small number of people.
A natural skin brightener found in wheat, rye and barley, azelaic acid (AZA) is most effective in concentrations of 20%, which is closely comparable in activity to 4% hydroquinone. In a study consisting of 329 melasma sufferers, half were treated with a 20% azelaic acid solution, and half were treated with a 4% hydroquinone solution. Of the patients treated with AZA, 56% had good to favorable results, while 73% treated with HQ had a similar result. However, when the AZA was combined with tretinoin or alpha hydroxy acids, the results were noticeably improved and rivaled the results of the high-concentration HQ. Azelaic acid also is antibacterial and anti-inflammatory, so it is effective in the treatment of rosacea and acne.
Arbutin(also known as alpha arbutin, bearberry extract or uva ursi extract)
A botanical, naturally-occuring cousin to hydroquinone, arbutin is derived from the bearberry plant (also known as uva ursi plant). Compared to HQ, arbutin has been shown to be significantly less cytotoxic to the melanocyte, making it a much safer, yet very effective, alternative to hydroquinone. In a clinical trial involving Japanese women with melasma, a 3% concentration of arbutin produced good to excellent results in 71.4% of patients within a three-month period.
One of the safest and most-gentle bleaching agents available, licorice extract is a potent anti-inflammatory and antioxidant. The ingredients responsible for the skin whitening aspect of the plant are known as glabradin and liquiritin. Liquiritin (in a 20% concentration) has been shown to provide good to excellent results in 70-90% of patients with hyperpigmentation and melasma with minimal side effects and only minor irritation.
Mulberry extract is derived from the root bark of the mulberry tree. Morus Alba L. Studies have confirmed it to effectively reduce tyrosinase activity at much lower concentrations than either hydroquinone or kojic acid.
N-acetyl glucosamine is a more stable form of glucosamine, an agent most widely known as an arthritis treatment. Recent studies have shown it to successfully reduce the amount of melanin in melanocytes by blocking tyrosinase conversion. Interestingly, the product's results improve significantly when combined with niacinamide (see below).
Inhibition of Melanosome Transfer
Some skin-bleaching agents lighten unwanted pigmentation by interfering with the transfer of melanosomes from the melanocyte to the keratinocytes. Niacinamide (or nicotinamide) is a biologically active form of niacin (vitamin B3) that has been shown to interrupt melanocyte transfer by 35-68%. The company Nia24 has built an entire brand around this key ingredient. NIA24 Intensive Recovery Complex is ultra hydrating and helps rebuild the skin's lipid barrier while effectively decreasing dark spots. RWJ 50353
RWJ 50353 is a thrombin-inhibitor used in medication as an anticoagulant. It also has been found to effectively reduce melanocyte uptake with no irritation or side effects.
Soybean Trypsin Inhibitor
Soybean Trypsin Inhibitor (STI) is a depigmenting agent derived from soybeans. STI reduces pigment in the skin by inhibiting the activation of a pathway necessary for the melanosome transfer to take place. In addition, STI has been shown to prevent UVB-induced pigmentation.
Other skin ligtening agents:
- Skin Turnover Acceleration
These compounds lighten pigmentation by increasing cell turnover, speeding up the removal of pigmented keratinocytes. The effectiveness of these agents are enhanced the most when combined with a bleaching agent that reduces active melanin production, ensuring that the old, pigmented keratinocytes are not replaced with newly hyperpigmented cells.
- Alpha Hydroxy Acids
Alpha hydroxy acids are fruit- and food-derived acids that increase exfoliation by loosening the bonds that hold together keratinocytes, allowing them to flake or fall off the skin more readily. There are several alpha hydroxy acids, the best-known ones being lactic acid (from milk and dairy), glycolic acid (from sugar), mandelic acid (from the bitter almond), citric acid (from citrus fruits), malic acid (from apples) and tartaric acid (from grapes).
- Mandelic Acid
Mandelic acid is an alpha hydroxy acid that stands out as being superior in the treatment of hyperpigmentation, due in part to its non-irritating properties. Irritation can actually increase pigment-producing activity, which is a potential drawback for the better-known bleaching agents like HQ and kojic acid. The most-remarkable feature of mandelic acid is its effectiveness in fading dermal melasma, a condition that typical bleaching treatments (hydroquinone, kojic acid, arbutin, azelaic acid, etc.) have difficulty treating without irritation. M2 Advanced High Potency Skin Refinish or Mama Lotion is a combination of mandelic and malic acids. The product is perfect for persistent dark spots but remains gentle on the skin.
Vitamin A derivatives, including tretinoin, retinol and retinaldehyde, trigger cell division in the skin, producing a more rapid cell turnover and exfoliation. As an added bonus, retinols encourage collagen production and thicken the dermis, thereby reducing the appearance and number of wrinkles. Retinols are potentially irritating, so when choosing a retinol product, it is best to start at the lowest strength and then work your way up to the higher concentrations. SkinMedica Retinol Complex comes in three different strengths, starting at 0.25% and going to 1.0%.
Safer and effective skin-lightening agents continue to be discovered as alternatives to the traditional hydroquinone. New skin-lightening peptides are being discovered and tested, and a variety of natural extracts exist that have various UV-protecting and melanin-suppressing activities. Examples of these natural ingredients are watermelon extract, stone crop extract and elder flower extract. The key to success with these more natural, gentle alternatives is long-term, consistent use.
How do I use bleaching products?
Bleaching products differ in recommended applications, but a few basic guidelines apply:
- Always wear a broad-spectrum sunscreen. The sun can deactivate hydroquinone. The sun is also responsible for contributing to pigmentation problems. If you want to solve hyperpigmentation, then you must avoid contributing factors, particularly exposure to the sun.
- Keep the routine simple. The fewer products you use, the less chance there is of irritation. Many bleaching products are aggressive, and it can be difficult to combine bleaching products with other skin care treatments without causing irritation. There are a few products that can enhance a bleaching cream's performance. These can include vitamin C products, tretinoin, a separate alpha hydroxy acid product, and special cleansers or toners to prep the skin. With the exception of the prepping products, it is wise to alternate the use of the two products rather than applying both at the same time. This will minimize the risk of irritation or adverse reactions. After a few weeks of use, some products may be applied together with the bleaching cream.
- If melasma is being treated, it is vital to keep using the product until permission is given from a doctor to stop. Sometimes, even if the melasma has faded to the point where it is no longer noticeable, it is still there. The only way to tell if the melasma is completely gone is with a Wood's lamp examination. Otherwise, it is very easy for the same spot to reappear.