Beauty 101

What is LHA? The Latest Skincare Acid Explained

Dr.Ingky Dermatologist
What is LHA? The Latest Skincare Acid Explained

When it comes to skincare, we often heard about alpha-hydroxy acids (glycolic acid, lactic acid), beta-hydroxy acids (salicylic acids), and maybe even polyhydroxy acid (PHAs), but are you brushed up on the new kid on the block, lipohydroxy acid? It is a chemical exfoliator for those whose skin may not tolerate salicylic acid but still want something that can help treat acne-prone skin. Lipohydroxy acid (LHA) is a beta-hydroxy acid (BHA), explains Dr. Ingky. LHA in particular is a salicylic acid derivative with higher molecular weight and stronger lipophilic properties, which means it’s able to dissolve in lipids and fats.

The Differences Among AHA, BHA, PHA & LHA

AHA stands for alpha hydroxy acid. As our dermatologist explains, AHAs are a series of acids, mostly derived from plant and animal sources, although some are synthetically produced. “Well-known AHAs such as lactic acid, malic acid, citric acid, and the most famous and the most popular glycolic acid, can be found in a variety of skincare products such as toners, exfoliators, and serums,” says Dr. Ingky.

Because of its function due to its small molecular size, it does two things. First of all, on the upper layer of the skin which we call the epidermis, AHA exfoliates the epidermal layer but after exfoliating it stimulates your skin to create a new epidermal layer in the process, which we call keratinization. AHAs are water-soluble, meaning they can’t penetrate through the skin’s natural oils. For this reason, they’re mostly used for their exfoliating properties on the skin's surface.

Beta Hydroxy Acid (BHA) is a slightly smaller family. A popular family member of BHA is salicylic acid. Salicylic acid and beta hydroxy acid are oil soluble. So, it's slightly different than AHA whereby AHA it's water-soluble. Why is oiling soluble so important? It means that if you apply a product with BHA on your skin, it seeks out areas with more sebum production or with more oil. Therefore, if you have whiteheads, blackheads, sebaceous filaments or even active acne, it will then act as a homing beacon for the salicylic acid. Then salicylic acid will move around your skin targets. Those particular areas with active sebum production or active sebum reservoirs like your clogged pores, and it gets into the pores and what it does? It exfoliates the pores. So, you can then reduce blackheads, reduce whiteheads, reduce your sebaceous filaments and reduce your acne. BHA is also great to kill off bacteria that cause acne because bacteria that cause acne is sensitive to salicylic acid.

So PHA, Poly Hydroxy Acid it's a particular new term being coined. Poly Hydroxy Acid was always known as an alpha hydroxy acid, so, it's a tier of AHA. However, because of its action, PHA products or PHA chemicals are generally quite large in molecular size, and because of the large molecular size, it doesn't really penetrate deep into the skin. It only affects the epidermal layer and on its own, PHA is not great. The different types of PHA that we have is lactobionic acid and gluconolactone. Now, this particular product comes from sugar and because it comes from sugar, it doesn't really bind or absorb your skin very well.

Hence that's why a lot of products in the market especially from Korea, combine the AHA with the BHA and the PHA as well. And once you've combined PHA with AHA and BHA, it produces a super serum or super cream. The reason because PHA stimulates more collagen production than AHA means that it's a great anti-aging chemical. It helps reduce acne scars as well. Just by using a combination of AHA, BHA, and the PHA product, not only do you reduce active acne, but you also reduce the scars and pigmentation. 

LHA are derived from salicylic acid and have a similar purpose. They are more fat soluble than BHA and more gentle because they penetrate the skin more slowly. Therefore, they are useful for exfoliating and treating acne in those with sensitive skin. LHA may also augment the anti-aging effects of tretinoin, an active form of vitamin A, by stimulating skin cell production.

Benefits of Using LHA

It Gently Exfoliates

According to the National Institute of Health, “The slow penetration of lipohydroxy acid (LHA) results in an individual cell-by-cell exfoliation that is associated with excellent tolerability,” compared to salicylic acid. When dead skin cell build up is sloughed away from the skin’s surface, it can appear clarified and refreshed.

It Can Help Promote Youthful-Looking Skin

To help address the natural visible effects of aging like fine lines and wrinkles, products formulated with LHA can reveal brighter-looking skin.

How to Use LHA Properly?

It is always recommended to consult your dermatologist before adding a new ingredient to your skincare routine. However, there are some simple facts that you should know if you’re considering trying something new for acne and LHA seems like a good candidate:

  • LHA is less acidic in nature compared to other acne fighting ingredients; hence, making it more tolerable for those with even the most sensitive of skin.
  • Be cautious about over-exfoliation! If you are adding LHA in your skincare routine, make sure you balance it out with the other products in your routine. Overdoing physical or chemical exfoliants can damage the protective barrier of your skin, making it even more sensitive to external factors.
  • Lastly, always do a patch test before using a new product!

AHA, BHA, PHA, LHA - How to pick the suitable acid for your skin concerns?

Everyone who is into skin care knows of AHA’s and BHA’s, the powerhouse ingredients that help in achieving skin goals. PHA’s and LHA’s, though less commonly known, are just as effective. To understand their benefits to our skin, here’s the lowdown.

AHA, alpha hydroxy acid, is derived from fruits, nuts milk or sugars. They are hydrophilic, meaning attracted to water. In skin care they work to break down the bonds between cells to make for easier exfoliation. AHA’s are water-soluble.

AHA’s are used in skin care to brighten skin by increasing exfoliation therefore aiding in cell turnover. Citric and lactic acid are among the most beneficial and popular due to both being compatible and having multiple benefits. 

BHA, beta hydroxy acid, is derived from willow tree bark, wintergreen oil or sweet birch. The most common BHA is salicylic acid. It is widely used in oil control and acne medications because of its lipophilic (attracted to oil) and keratolytic softening of skin to improve moisture binding) properties. It is able to penetrate the oils in the skin and clear pores of excess debris and dead skin cells. Beta hydroxy acids are oil soluble.

PHA, poly hydroxy acid, functions the same as AHA’s but are gentler and less irritating due to its larger molecule size. This makes PHA’s very beneficial in treating sensitive skin types that are prone to AHA irritation. PHA’s have anti-inflammatory and antioxidant benefits as well as assisting with exfoliation.

LHA, lipo hydroxy acid, are a type of BHA that is similar to salicylic acid but more lipophilic. They penetrate less deeply into cells and have the same pH as skin (5.5). This makes LHA’s very gentle with no irritation.

LHA’s are preferred in treatments for sensitive skin that may or may not have acne as well as a treatment for rosacea. They are anti-inflammatory, antibacterial and mimic the effects of tretinoin which is the active ingredient in professional Retin-A products. It helps in the unclogging of pores and enhancing cell production.

Since AHA’s are water-soluble, they are best used on skin that is clean and completely dry. Any dampness on the skin will hamper the benefits and results. BHA’s, being oil soluble, should be applied to skin that is freshly cleansed and dried. If you use toner, use one that is suitable for oily skin. Apply BHA’s after toner and allow a minute or two for it to “soak in” before applying any moisturizers. Here’s are the quick lowdown:


  • Glycolic or lactic acid are the most popular and suitable for almost all skin types. These are great for exfoliation.
  • AHA’s are used to rejuvenate and brighten the skin. Good for hyperpigmentation.
  • Lactic acid should be your choice of AHA if you have sensitive skin.


  • Great for exfoliation of oily skin and normal/combo skin that tends to be more oily
  • Helps with acne and keeps skin free from impurities
  • Helps to unclog pores and clear out dead skin cells and excess oil


  • Choose gluconolactone for gentle exfoliation on dry or normal/combo skin
  • Brightens and renews skin, helps with hyperpigmentation for skin that can be sensitive
  • Reduces acne lesions without irritating


  • Best for exfoliation of sensitive skin or oily skin that tends to also be sensitive
  • Helps clear acne and pore debris
  • Good for rosacea

In the standard beauty market, AHA’s and BHA’s will be the most widely used and purchased. PHA’s are found in some products but not as widely marketed. Meanwhile, LHA’s are found in higher end products and prescription skin care from a dermatologist.

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