Tranexamic acid, arbutin acid, vitamin C, glycolic acid, azelaic acid, niacinamide… These are just some of the active ingredients for dark spots used in skin care products. What are the differences in their mechanism of action? Which are the best hyperpigmentation ingredients?
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- Active Ingredients
- What Are the Best Ingredients for Hyperpigmentation in Skincare?
What Are the Best Ingredients for Hyperpigmentation in Skincare?
- What Are Dark Spots?
- Origins and Mechanisms of Action of the Main Hyperpigmentation Ingredients
- Which Are the Best Ingredients for Hyperpigmentation of Different Types?
- Sources
What Are Dark Spots?
Hyperpigmentation is the dermatological term used to describe the persistent dark spots that appear on the skin's surface. This phenomenon occurs as a result of a disturbance in the pigmentation process: melanin, the pigment responsible for the skin's natural coloring, is overproduced in certain areas. The resulting blotches vary in size and impact the evenness of the complexion. Hyperpigmentation can be divided into three categories:
Melasma or pregnancy mask, caused by hormonal imbalances;
Solar lentigo, also known as age spots or sun spots, caused by excessive exposure to UV rays;
post-inflammatory hyperpigmentation, resulting from overproduction of melanin after inflammation (wounds, burns, blemishes, acne flare-ups).
Please note: The use of certain perfumes and medications such as oral contraceptives, anti-malarial drugs and Imipramin can also cause hyperpigmentation.
Origins and Mechanisms of Action of the Main Hyperpigmentation Ingredients.
In the world of beauty, more and more ingredients that lighten skin are being developed. Below is a non-exhaustive list of the best ingredients for hyperpigmentation.
Niacinamide
Also known as vitamin B3, nicotinamide or vitamin PP (Pellagra Preventive), niacinamide is a water-soluble B-group vitamin with antioxidant, antibacterial and anti-inflammatory properties. With regard to its anti-spot activity, it inhibits the transfer of the melanosomes from melanocytes to keratinocytes. As a reminder, skin pigmentation is a complex process that begins within cells called melanocytes, which themselves contain organelles (melanosomes) in which melanin is synthesized. These melanosomes are then transferred to the surrounding keratinocytes, which subsequently transport the pigment and eventually degrade it.
Tranexamic acid
This is a synthetic derivative of lysine, an amino acid found in the skin. It was only recently discovered by a health professional that it is one of the ingredients that lighten skin. Its mechanism of action is based on inhibition of the release of inflammatory mediators involved in triggering melanogenesis. Several studies have shown this active ingredient to be particularly effective in reducing the appearance of melasma, or pregnancy masks, as well as sunspots.
Glycolic acid
Of natural or synthetic origin, glycolic acid is the shortest of the alpha-hydroxy acids (AHA). Its ability to stimulate skin cell renewal enables it to correct skin damaged by UV rays (sun spots), dull skin and erase the marks left by imperfections. By penetrating deep into the skin thanks to its small size, it regulates the action of melanocytes in melanin production, reducing the appearance of pigmentation spots.
Alpha-arbutin
Of natural origin (derived from bearberry leaves) or synthetic, alpha-arbutin, also known as arbutin acid, is a fairly recent anti-spot active ingredient. When applied to the skin, its remarkable efficacy is due to its perfect affinity with the active site of tyrosinase, an enzyme involved in melanin formation. This competitive inhibition of the enzyme's active site blocks its activity and, consequently, melanin synthesis. The equation is simple: less tyrosine and less melanin means less pigment, fewer brown spots and a more even skin tone.
Azelaic acid
This compound is a dicarboxylic acid found naturally in wheat, rye, and barley. It is recognized for its anti-comedogenic, antibacterial and anti-spot effects. Azelaic acid's mode of action against hyperpigmentation has been discovered: It reduces the capacity of melanocytes to produce melanin by inhibiting the tyrosinase enzyme and regulating the activity of the thioredoxin reductase enzyme. Furthermore, it targets only pigment-laden or atypical melanocytes. As a result, it does not interact with healthy cells. What's more, thanks to its antioxidant properties, azelaic acid protects the skin from the free radicals responsible for the appearance of signs of aging, including dark spots.
Vitamin C
This skin care essential needs no introduction! Vitamin C (or ascorbic acid) protects against free radicals, smoothes tired features and brightens dull complexions: it's the ultimate radiance booster. In dermatology, several studies have demonstrated vitamin C's depigmenting power. Its mechanism of action is based on inhibition of tyrosinase, an enzyme responsible for converting the amino acid tyrosine into melanin, thereby reducing pigmentation. For example, one study demonstrated that a 20% vitamin C serum is capable of reducing signs of photoaging, including dark spots caused by UV rays.
Licorice extract:
Named INCI “Glycyrrhiza Glabra Root Extract”, licorice extract contains 95% glabridine, a compound involved on several levels in regulating the phenomenon of hyperpigmentation. It considerably reduces the amount of endothelin-1 (a mediator involved in the pigmentation process) released by keratinocytes after UV exposure. In addition, it inhibits the activity of phospholipase A2 (PLA2), an enzyme released by epidermal keratinocytes after UV exposure or during inflammation, which stimulates tyrosinase activity and hence melanogenesis. Other active compounds, such as glabrene, isoliquiritigenin licuraside, isoliquiritin and licochalcone A, isolated from licorice extracts, have also been shown to inhibit tyrosinase.
Which Are the Best Ingredients for Hyperpigmentation of Different Types?
Although all the active ingredients listed in the previous paragraph are active on all three types of pigmentation spots, some are more relevant than others in specific cases.
In the case of melasma (or pregnancy mask), according to scientific studies conducted over the last few years, they have all, without exception, demonstrated interesting activity in reducing their appearance.
To combat acne marks or post-inflammatory hyperpigmentation, niacinamide, licorice extract and azelaic acid stand out.
For sun spots caused by overexposure to UV rays, vitamin C, tranexamic acid and arbutin-acid are excellent compounds to include in your daily skincare routine, either separately or together. These three compounds are not photo-sensitizing and can be used in the morning. They limit the overproduction of melanin generated by UV rays during the day.
Sources
TELANG PS. Vitamin C in dermatology. Indian Dermatol Online J (2013).
BUI T. P. & al. Azelaic acid: pharmacokinetic and pharmacodynamic properties and its therapeutic role in hyperpigmentary disorders and acne. International Journal of Dermatology (1995).
H. MOHAMMADAMINI & al. A comprehensive review of the therapeutic potential of alpha-arbutin. Phytotherapy Research (2021).
THAPPA D. M. & al. Comparative study of trichloroacetic acid versus glycolic acid chemical peels in the treatment of melasma. Indian Journal of Dermatology, Venereology and Leprology (2010).
BOISSY R. E. & al. The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer. British Journal of Dermatology (2002).
MONCADA B. & al. A double-blind, randomized clinical trial of niacinamide 4% versus hydroquinone 4% in the treatment of melasma. Dermatology Research and Practice (2011).
WANG J. V. & al. Tranexamic acid for melasma: Evaluating the various formulations. Journal of Clinical and Aesthetic Dermatology (2019).
Yong Chool Boo, Arbutin as a Skin Depigmenting Agent with Antimelanogenic and Antioxidant Properties, Antioxidants, (2021).
Joseph Bikowski, Managing Melasma with Azelaic Acid Gel, Practical Dermatology, (2008).
Haikh ZI, Mashood AA. Treatment of refractory melasma with combination of topical 5% magnesium ascorbyl phosphate and fluorescent pulsed light in Asian patients. Int J Dermatol. (2014).
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