As far as chemical exfoliants go, there were times when we used to be confused about AHA or alpha-hydroxy acids (glycolic acid, lactic acid) and BHA or beta-hydroxy acids (salicylic acid). When we think that we already get the hang of it comes a new kid on the block, PHA or polyhydroxy acid. Then, we feel like an expert who knows everything there is to know about chemical exfoliant in a skincare routine. Sorry, hold that thought because I will introduce you to yet another member of the acid family: LHA, aka lipohydroxy acid. Many of you may not be familiar with lipohydroxy acid, but as it turns out, it was first developed by L'Oréal researchers in the 1980s. Surprise, surprise! I bet your head is filled with a lot of questions right now. Read more to satisfy your curiosity!
What is LHA? How does it differ from Salicylic Acid (BHA)?
Lipohydroxy acid (LHA), or 2-hydroxy-5-octanoyl benzoic acid, is a salicylic acid derivative called capryloyl salicylic acid. The chemical structure of LHA made up of a long-chain fatty acid that makes it becomes more lipophilic, meaning able to dissolve in oil or sebum than salicylic acid. This allows lipohydroxy acid to penetrate into the sebum-enriched pilosebaceous unit. Furthermore, LHA has a big molecular size, so it cannot go through as deeply as salicylic acid. It also penetrates the skin slower compared to its BHA parent. However, due to its lipophilic nature and slow penetration rate, lipohydroxy acid can exfoliate dead skin cells from the outer layer of the skin more thoroughly, almost like mimicking our physiologic desquamation (skin shedding). In contrast, BHA works more rapidly and aggressively in getting rid of the skin cells, which is likely too harsh for sensitive skin. Also, compared to many other chemical exfoliants that tend to be more acidic, lipohydroxy acid has a pH similar to that of normal skin (5.5), which makes it more gentle and less irritating.
Comparison of BHA vs LHA
Benefits of LHA in skincare?
Gentle chemical exfoliant
Age, environmental stress, hormones and other factors affect our skin to shed slower than its normal pace (around 28 days). As a result, dull, rough and flaky skin may occur. One of the most effective ways to prevent this from happening is to enhance skin cell turnover by exfoliation. The fact that lipohydroxy acid slowly penetrates and gently exfoliates the skin surface cell-by-cell makes it possible for our skin to tolerate it, which in turn improves skin dullness and texture, improving skin clarity and leaving a healthy, radiant complexion.
Clears clogged pores
When debris meets sebum and dead skin cells, it can cause blockage of the pores. Lipohydroxy acid is an excellent comedolytic agent. The lipophilic nature of LHA allows it to penetrate the sebum-rich sebaceous glands to unclog the pores by dissolving the mixture of sebum and dead skin, preventing the formation of whiteheads and blackheads that may eventually develop into acne. According to a study published in 2016, lipohydroxy acid effectively decreases the size and number of comedones.
A few factors contribute to acne, for instance, acne-causing bacteria and abnormal sloughing off of skin cells. Propionibacterium acnes is one of the most common bacteria that partake in the formation of acne. Lipohydroxy acid can stay inside the sebaceous follicle. Along with the antimicrobial and anti-inflammatory properties that lipohydroxy acid has, it helps treat existing acne and reduce future breakouts. In addition to that, regular exfoliation also aids in reducing the barrier of the dead skin cells that tend to clog pores. Using lipohydroxy acid as a first step also allows acne-fighting products to absorb better into the skin and work more effectively.
As if popping on our face every now and then is not enough, acne does not go down without a fight. Yes, it leaves blemishes here and there on our skin that takes time to fade out. That's why including lipohydroxy acid in your skincare routine may be beneficial. LHA helps to even out skin tone by exfoliating the pigmented upper layer of our skin, accelerating skin cell turnover and inhibiting melanin formation. Therefore, lipohydroxy acid can also be used to correct other hyperpigmentation issues.
Promotes cell renewal
We know how damaging UV exposure is to the skin. It can cause pigmentation changes (i.e. sun spots, freckles) or decreased elasticity of the skin, resulting in the appearance of fine lines and wrinkles. Lipohydroxy acid has been shown to improve blood flow and increase the stimulation of structural skin proteins and lipids, such as glycosaminoglycan, hyaluronic acid, collagen and elastin, thereby boosting the growth of new skin cells. By doing so, LHA effectively maintains skin's elasticity and firmness that can also help reduce signs of photoaging. The efficacy of LHA is comparable to the effectiveness of using tretinoin (also known as retinoic acid) which is the gold standard in the treatment of photoaged skin.
Suitable for sensitive skin
A few characteristics that make lipohydroxy acid is gentle, non-irritating and well tolerated by even the most sensitive skin are its pH level that is similar to skin's pH and its slow penetration.
How to use it?
Incorporate exfoliation into your skincare routine two to three times a week. Or, you can use it according to the instruction on the product's label. However, there's no general rule as to the frequency to exfoliate. It varies from person to person, depending on your skin's condition, products type and concentration, as well as your skin's tolerance to it. Even though lipohydroxy acid is very gentle and suitable for sensitive skin, still approach with caution as to not over-exfoliate and compromise your skin barrier. It is better to start slow (frequency) and low (concentration), then you can gradually and mindfully increase the frequency and concentration. Listen to your skin. If it shows any signs of irritation (such as redness, itchiness, stinging sensation), stop exfoliating and focus on soothing and calming your skin first.
If you just started adding lipohydroxy acid into your skincare routine, I do not advise using other exfoliating ingredients, vitamin C and retinol afterwards. It may be too much for your skin to handle, especially those with sensitive skin type. Just use it one at a time and observe how your skin reacts to it. You can slowly step up your game by alternating the use every other night or at different times of the day.
With a variety of acids widely available in the market, you might get confused from time to time when choosing between varying chemical exfoliants. Nevertheless, they all serve the same purposes for our skin: to exfoliate, unclog pores, tackle acne formation, fade out blemishes, etc. Different types of acids may do their job a tad differently from one to the others, and some may be more effective than its 'rivals', but it all comes down to choosing an acid that suits your skin type and skin condition. That being said, it does not mean that lipohydroxy acid is more superior to salicylic acid; the former offers a more gentle and better-tolerated exfoliation because of its larger molecular size that results in slower, less-deep skin penetration.
ACWELL Real Aqua Balancing Toner
Liquorice root extract: An extract from the root of Glycyrrhiza glabra has amazing skin-brightening effects. It inhibits the production of tyrosinase, therefore obstructing melanin synthesis. It also offers antioxidant and anti-inflammatory benefits.
Hyaluronic acid: A polysaccharide that is naturally found in your skin. It retains moisture, keeping your skin moisturised and radiant. It can absorb into the skin quickly. Plus, it is non-irritating and safe for use with all skin types.
Houttuynia cordata extract: An antioxidant-rich ingredient that can soothe and calm irritated skin. Besides, it also possesses antimicrobial and anti-inflammatory properties suitable for oily, acne-prone, and sensitive skin.
Propanediol: A colourless liquid derived from corn sugar. It is an excellent solvent for salicylic acid. With the help of propanediol to dissolve the ingredients and decrease the product's viscosity, it can result in optimal absorption of each ingredient. There are many reasons why propanediol is commonly used in skincare products. It hydrates the skin and locks moisture in, for instance.
Tricholoma matsutake extract: Brightens complexion and fades pigmentation by inhibiting tyrosinase activity, decreasing melanin formation. Furthermore, mushrooms are a source of kojic acid that inhibits melanin production and works well when paired with other skin-brightening ingredients. Moreover, it has anti-wrinkle, antibacterial and anti-inflammatory properties.
Rhododendron chrysanthemum leaf extract: A soothing ingredient that helps to protect the skin against harmful external factors. It can also mask the scent of other ingredients.
Oxygen: It increases the delivery of the skincare ingredients directly into the skin.
- By Claudia Christin (@funskincare)
MBBS, Ph.D. (Dermatology)