Understanding what hydroquinone is, how it works, and why it is so sort after is will help us in our venture of recognising which top 10 alternative ingredients for hydroquinone will be the most suitable.
What is Hydroquinone?
Hydroquinone is most studied to date, and is also considered to be the “gold standard” when it comes to lightening agents. Hydroquinone typically a topical treatment that comes in concentrations ranging from 2% to 4%, although higher concentrations are only made available by prescription. While hydroquinone is generally considered safe for use in skin care products, there is some controversy and concern surrounding its safety. As a result, hydroquinone is banned in some countries and is available only by prescription in others. It is important to use hydroquinone-containing products only as directed and under the guidance of a healthcare professional.
To know which ingredients can be used an alternative to hydroquinone, let’s first understand how skin-lightening agents work.
How Do Skin-Lightening Agents Work?
Different lightening agents in the market work in a their different ways. Skin-lightening agents commonly work by reducing the production of melanin, the pigment that gives colour to our skin, hair, and eyes. Melanin is produced by specialised skin cells called melanocytes, and its production is influenced by factors such as genetics, sun exposure, and hormonal changes.
Skin-lightening agents work in a few different ways to reduce melanin production. Some agents, such as hydroquinone, mequinol, azelaic acid, arbutin, and licorice extract work by inhibiting the activity of an enzyme called tyrosinase, which is involved in the production of melanin. By blocking tyrosinase, these agents can help reduce the amount of melanin produced by melanocytes.
There are skin-lightening agents that also work by interfering with the transfer of melanin from melanocytes to skin cells. For example, kojic acid inhibits the activity of an enzyme called glycosyltransferase, which is involved in the transfer of melanin from melanocytes to keratinocytes (skin cells). By blocking this transfer, kojic acid can help reduce the amount of melanin that ends up in the skin.
Some lightening agents such ascorbic acid (vitamin C) and niacinamide, work by reducing oxidative stress and inflammation in the skin which can help to improve the overall health of the skin and reduce the appearance of hyperpigmentation.
Lightening agents can also work by:
1. Slowing down production of tyrosinase enzyme (N-Acetylglucosamine)
2. Preventing melanin from travelling from melanocytes to skin cells (Soy, Niacinamide, Retinoids)
3. Dispersing pigments (Licorice Extract)
4. Increasing skin turnover, meaning less pigments to go around (Alpha and Beta Hydroxy Acids [AHA, BHA], Retinoids)
Here’s the exciting bit, the top 10 alternative ingredients for hydroquinone!
The 10 Alternative Ingredients for Hydroquinone
Mequinol is the main alternative prescription to hydroquinone. It is not entirely clear how mequinol works, but it appears to work similarly to hydroquinone. It mimics tyrosine and decreases tyrosinase’s ability to produce melanin. Mequinol commonly comes in concentrations of 2% and sometimes in combination with 0.01% tretinoin and ascorbic acid to enhance penetration. It is supposed to be less irritating than hydroquinone but can sometimes cause temporary postinflammatory hyperpigmentation (PIH). Rarely, it can lead to reversible depigmentation.
Retinoids are Vitamin A analogues used for treating many conditions such as acne, sun damage, as well as acting as a penetration enhancer for other treatments. Examples of retinoids are: tretinoin, adapalene, tazarotene, isotretinoin (prescription) and retinol (non-prescription). Retinoids are thought to work in multiple pathways to reduce pigmentation, increase skin turnover, interrupt melanin transfer to skin cells, reduce tyrosinase production in skin, and dispersal of melanin. Retinoids are commonly used in combination with other treatments to treat hyperpigmentation. It is expected that this treatment process will take several months to achieve ideal results. In general, the more effective a retinoid is, or rather the higher the concentration, the more irritating its side effects. Common side effects include redness, dryness, and peeling. PIH is also a risk, especially in darker skin.
3. Azelaic Acid
Azelaic acid is another common alternative to hydroquinone. Azelaic acid is actually produced by a fungus which sometimes infects humans and causes light patches of skin. It is slightly milder than hydroquinone but can come close to the effects of hydroquinone when it is used in conjunction with retinoids. Azelaic acid works by interfering with the tyrosinase activity. Tyrosine mimic, suppresses, and kills abnormal melanocytes. Azelaic acid is known for its little side effects, which commonly involves mild stinging and redness.
Arbutin is sometimes also referred to as the “natural hydroquinone”. Its chemical structure is very similar to that of hydroquinone’s. It is found in extracts of bearberry leaves, and to a lesser extent in cranberry and blueberry leaves. It works in our bodies by slowly turning into hydroquinone and acting as a tyrosine mimic to slow down production of melanin. It also interferes with maturation of melanosomes. There are mixed conclusion in studies regarding the efficacy of Arbutin. The most common formulation is 5% although higher formulations are also available. Risks of higher concentrations of arbutin includes the risk of PIH.
5. Kojic Acid
Kojic acid is produced by a bacteria found in the fermentation of rice while manufacturing Sake. A derivative of kojic acid, kojyl-APPA, has also been investigated for its whitening effect and its ability to improve skin penetration. It works by binding itself to copper in tyrosinase, which results in preventing the enzyme from producing melanin normally. Kojic acid is often combined with hydroquinone, retinoids, glycolic acid, emblica extract or corticosteroid. Kojic acid can be very irritating and is also a potential allergen. Preparations prior to the use of Kojic acid typically includes the use of steroids to reduce the chances of a reaction.
6. Licorice Extract
Licorice extract is extracted from the root of the licorice plant (Glycyrrhiza glabra), and is widely used as a whitening ingredient in cosmetics. Its main effects are through two whitening components, glabridin and liquirtin. Glabridin protects skin from UV-B induced pigmentation whilst also acting on tyrosinase to slow down melanin production. Liquirtin on the other hand, disperses melanin. Licorice extract contains a number of antioxidants and anti-inflammatory chemicals which are very beneficial for the skin, and is also likely the reason why licorice extracts are mild and have few side effects.
7. Ascorbic Acid (Vitamin C)
Ascorbic acid is an ingredient in many skincare products and is widely popularised in the skincare industry. It is a potent antioxidant, but is very unstable and is usually combined with other ingredients to treat hyperpigmentation. Ascorbic acid works by turning dopaquinone back into L-DOPA, undoing the reaction that tyrosinase does. It is less irritating than hydroquinone and has an excellent safety profile. Interested in Vitamin C treatment options? Try out Ionto Vita C facial for yourself!
N-acetylglucosamine is a sugar found abundantly in nature and is a precursor of hyaluronic acid. It works by slowing down the production of tyrosinase, and has been found to improve pigmentation at 2% in clinical studies. N-acetylglucosamine is often used in conjunction with niacinamide. Occasionally, N-acetylglucosamine can cause mild to moderate skin irritation.
Niacinamide is also known as nicotinamide or Vitamin B3. It is an antioxidant, but unlike vitamin C, niacinamide is very stable. It works by inhibiting the transfer of pigments to skin cells. Several studies have shown that niacinamide is the most effective at 2-5% concentration for reducing hyperpigmentations. Although niacinamide is a stable ingredient, some skin irritation can still occur.
Cysteamine is the new kid on the block when it comes to treating pigmentation. It is a chemical compound that can be biosynthesized in mammals (this includes humans!) by degradation the enzyme, co-enzyme A. Cysteamine was conventionally used as a treatment for cystinosis. Recently, ScientisPharma had compounded it into a 5% cream for the treatment of hyperpigmentation for overall skin lightening. Cysteamine is a metabolite of L-cysteine which inhibits melanin synthesis. The way it is thought to work includes inhibition of tyrosinase and peroxidase, scavenging of dopaquinone, chelation of iron and copper ions, and increasing intracellular glutathione. Randomised controlled trials have confirmed the efficacy of cysteamine cream in the treatment of epidermal melasma. Side effects are generally mild, with temporary heating up or burning sensation and redness that is typically short-lived.
Those were the top 10 alternative ingredients for hydroquinone. When choosing an alternative to hydroquinone, it is important to consider the concentration of the ingredient, the formulation of the product, and any potential side effects. Some ingredients, like vitamin C, can be unstable and may require special formulations to be effective. It is also important to use these ingredients only as directed and under the guidance of a doctor to minimise the risk of side effects. Good luck in your journey to clearer skin!