Skincare Science:
Lightening creams

Introduction

In the last post, we discussed the importance of regularly using sunscreen. What if you already have uneven skin pigmentation? Sunscreen won’t reverse existing problems, so what are your over-the-counter options? Cosmeceutical companies often sell lightening creams or brightening creams that promise to improve skin pigmentation. Of course, there is no clear industry definition of what a lightening or brightening cream is. So we have to look at the ingredient list to figure out what a cream does.

There are several types of chemicals commonly found in these creams. Each type attacks the pigmentation problem in a different way. You’ll often find that brightening creams will include compounds from more than one category to increase the combined effect.

Tyrosinase inhibitors

An albino lion roaringAlbino animals don’t have a working tyrosinase enzyme

These molecules short circuit melanocytes (the pigment producing cells in the epidermis). More scientifically, they inhibit the enzyme tyrosinase found in melanocytes. This enzyme is a key player in the production of melanin. However, stopping the production of melanin does not immediately lighten the skin. Although melanin is produced by melanocytes, it is absorbed and held by all the other cells of the epidermis. So the skin will gradually lighten over time as old skin cells are shed and new ones (with less melanin) take their place.

There are three main compounds in this category:

Hydroquinone

2% is the maximum concentration you can get over the counter – any higher (usually 4%) and you need a prescription. Long term use of high concentration hydroquinone has been associated with a permanent yellowish pigmentation of the skin called ochronosis. This is very rare and only reported after years of use. The European Union banned hydroquinone for use in over the counter skin lightening creams. The FDA is carrying out testing of hydroquinone to make sure it is safe. For now, it remains available in the US.

Kojic acid

Kojic acid is usually a little more expensive than hydroquinone. Most studies suggest that it has similar effectiveness to hydroquinone. It also has antioxidant properties, so it is often added to food as a preservative. You’ll often find this in lightening skin creams.

Azelaic acid

Again, most studies suggest that Azelaic acid has similar effectiveness to Hydroquinone and Kojic acid. It does have a slightly higher rate of side effects like burning and stinging. Azelaic acid also reduces inflammation and kills bacteria – so it is often used to treat acne and rosacea.

Arbutin

Arbutin is closely related to hydroquinone. In fact, it can actually be made from hydroquinone. Like Kojic acid, it is a bit more expensive than hydroquinone. There aren’t any significant safety concerns with Arbutin. It was declared safe for use on the face, neck, or hands by the SCCS (the European consumer safety commission) in 2015.

Exfoliants

Peeling painted wood

Exfoliation is like sanding down old floorboards to reveal the beautiful wood grain below

These chemicals slough off the top most layers of your epidermis. Tyrosinase inhibitors reduce future pigment production, but exfoliants can treat the existing pigment. By peeling the upper layers of skin, uneven pigment is quickly removed. But without a tyrosinase inhibitor added on, the results can be short-lived, as the skin just produces more pigment.

There’s two main types of exfoliants:

Tretinoin and related retinoids

This includes retin-A, Vitamin A, retinol, retinoic acid, and tazarotene. They act by speeding up the rate at which skin cells are naturally shed and new ones are made. We’ve covered the retinoids in a previous blog post – check it out to learn more about them.

AHAs and BHAs

These are weak acids that chemically peel off the top layers of skin. The common ones are glycolic acid, lactic acid, citric acid, and salicylic acid. We’ll go into more detail on these in a future post on chemical peels.

Steroids

Its not entirely clear how steroids reduce pigmentation, although there is no doubt that they do. Its possible that they reduce the activity of the pigment producing skin cells (melanocytes). Steroids are also useful because they reduce the side effects (such as burning and stinging) of other lightening agents. They’re quite safe when used for short periods under the direction of a doctor. Unfortunately, steroids have unpleasant side effects when they are used over a long period of time. Steroids can cause stretch marks (due to thinning and weakening of the skin). They can also lead to high blood sugar, weight gain, and hormonal imbalances.

There are a plethora of steroids – too many to name – but some common ones are: hydrocortisone, triamcinolone, betamethasone, and dexamethasone.

Conclusion

Improving skin pigmentation should ideally be a war fought on multiple fronts. Production of new pigment should be decreased, while also improving the existing pigment. Most skincare will contain several of the chemicals we’ve discussed here for this synergistic effect. Finally, there are usually prescription or professional versions of most over-the-counter creams, that use higher concentrations of the active ingredients. The key is making sure you are on a consistent skincare regimen. And remember: prevention is better than a cure!

Footnotes

  1. EU cosmetics directive about hydroquinone
  2. Skin-lightening products revisited. Petit L, Pierard GE. Int J Cosmet Sci 25
  3. Azelaic acid in the treatment of papulopustular rosacea: a systematic review of randomized controlled trials.
  4. SCCS opinion on Arbutin