Everything You Need to Know About Exfoliating with AHA, BHA, PHA

aha bha exfoliant scrub skincare

Our skin naturally sheds layers of dead cells which accumulate over time. This happens invisibly on a regular basis, but the older we get, the slower this process gets. Aging, environmental damage, and sun exposure all contribute to the slowdown of the natural exfoliating process. So, as a result, our skin ends up looking prematurely aged and dull. AHA’s and BHA’s are chemical exfoliators which can aid in speeding up the exfoliation process – revealing younger, smoother, and even-looking skin.

In this article, we explore the difference between chemical exfoliators, how they benefit you, and which one you should use.

Alpha Hydroxy Acids (AHA) works on the skin’s uppermost layers - giving it a smoother look, reducing sun damage and hyperpigmentation. Also, because it’s naturally hydrating, it’s recommended for those with drier skin.

Beta Hydroxy Acids (BHA) is oil soluble, so it can penetrate into skin’s deeper layers. Because of that, BHA is ideal for people with oilier skin, clogged pores, and acne.

How Do Chemical Exfoliators Work?

The word “chemical” may sound scary, but in reality it’s both safe and simple to use. All chemical exfoliators fundamentally work similarly – they break down the adhesive holding dead skin cells together, allowing them to shed, and making way for new skin cells to be revealed.

Side note: retinol is not an exfoliator. It work’s fundamentally differently – it doesn’t weaken the skin bond, instead it ‘tells’ new skin cells to grow ‘normally’.

Exfoliation is an important step in your skincare regimen because it has a wide range of benefits for basically everyone. Exfoliation delivers general anti-aging benefits because it increases skin cell turn over: the rate where old skin is shed, and new skin is revealed.

How is Chemical Exfoliation Different from Scrubbing?

When the word ‘exfoliation’ comes to mind, many of us visualize using something to scrub off dead skin. The truth is that this is the roughest method of exfoliation, and at best deliver mediocre results. This method of exfoliation known as mechanical or physical exfoliation and only removes the skin’s topmost layer.

Physical exfoliation isn’t nearly as effective on deeper levels than even the weakest of chemical exfoliators. It’s still an option, but it shouldn’t be the main way that you exfoliate.

Read more about scrubbing here

What is AHA

AHA’s work on the topmost layers of skin because it’s only water soluble. It’s also naturally hydrating so it does benefit dry skin and those suffering from dehydrated skin. They also provide other benefits such as firming, smoothing, and brightening. AHA’s are great for those who are looking to reduce sun damage, hyperpigmentation, and uneven skin.

AHA’s are found in many fruits (citruses), as well as dairy products. But, in cosmetics, they are usually man-made.

There are several kinds of AHA’s to pick from to accommodate people with various skin sensitivities. There is a direct link between effectiveness and gentleness with regards to the different forms of AHA. The bigger an AHA’s molecule is, the slower it can penetrate the layers of skin – resulting in a milder but less effective AHA.

General concentrations of AHA in skincare products vary between 4 to 15%, and peels typically contain higher concentrations. For daily, or more regular exfoliation, we suggest concentrations between 5 and 10%.

Forms of AHA

Glycolic Acid

Glycolic acid is the most typically used form of AHA and is regarded as the standard for AHA’s.

The molecule size is the smallest, and as such, it has the best ability to get through the skin’s most uppermost layers. Because glycolic acid is a humectant, it can direct water to the skin’s most upper layers to moisturize it.

Sugarcane is the main source of glycolic acid, but synthesized glycolic acid is generally found in skincare products as it’s simpler to stabilize and formulate with other ingredients.

Lactic Acid

Lactic acid does all the things that glycolic does, but more gently and slowly. Originating from milk, lactic acid is a moderately bigger molecule, and that’s why its penetration rate is slower. However, lactic acid can still effectively act as a lone exfoliator. You’ll often see it as an ingredient in several AHA exfoliators.

Malic Acid

Malic acid originates from apples. It has a bigger molecule size in comparison to glycolic and lactic acids. In AHA products, it tends to be used as a supporting acid rather than a lone ingredient (such as glycolic or lactic acid). It offers multi-level exfoliation when used with other AHA’s.

Tartaric Acid

Contained in red grapes, tartaric acid is approximately double the size of glycolic acid. But in similar concentrations to glycolic acid, it can still provide exfoliation benefits. Tartaric acid is often used in formulations as a pH adjuster so that ingredients can deliver its intended benefits.

Citric Acid

Derived from citric fruits like oranges and lemons. Although it can be used alone in greater concentrations, citric acid is quite acidic (approximate pH of 2.2), and as such, can irritate sensitive skin.

Similar to tartaric acid, citric acid tends to be used as a pH adjuster and an antioxidant in products.

Mandelic Acid

Mandelic acid is the biggest AHA and originates from bitter almonds. Mandelic acid hasn’t been researched enough to determine what it’s best used for. As such, you won’t see it listed on many skincare formulation ingredient labels. However, it does offer potential for people with sensitive skin due to its mildness and slow penetration rate.

What is BHA

Beta Hydroxy Acid (BHA) works very much like AHA’s because it loosens the adhesive that binds skin cells. Unlike AHA, BHA is oil-soluble, so it can penetrate deeper into skin layers and pore linings for deeper exfoliation.

Additionally, BHA is naturally anti-bacterial and anti-inflammatory, making it soothing. This is the reason why BHA is recommended for people with acne-prone or oily skin. However, all skin types can benefit from BHA because it can address a variety of concerns such as:

  • Milia (Whiteheads)
  • Acne
  • Dull Skin
  • Blackheads
  • Chicken Skin (Keratosis Pilaris)
  • Rough or Bumpy Skin
  • Rosacea
  • Enlarged Pores
  • Psoriasis

BHA products tend to be sold in 0.5 to 9% concentrations. To see results through regular use, we suggest a rate between 1 and 2%.

Betaine Salicylate

Although salicylic acid is essentially the BHA in modern skincare products, some exfoliators contain betaine salicylate instead, which is a milder and weaker BHA derivative. It’s typically seen in K-beauty products because of the regulatory limits of salicylic acid in Korea. It takes approximately twice the betaine salicylate concentration to have the same effect as salicylic acid.

What is PHA

Polyhydroxy Acids (PHA) is the newest form of exfoliating acids which are gaining in popularity in many skin care products. Like AHA and BHA, they refer to a group of acids, but the most common ones are Gluconolactone acid and Lactobionic acid.

They work similarly to AHA – exfoliating the topmost layers of skin but touted to be gentler than them due to its larger molecular structure. Despite it being gentler, its supposedly doesn’t hamper its effectiveness. If you have extra sensitive skin, this is something that we would recommend you try.

Exfoliator Acidity

pH ScaleAlthough active ingredient percentage concentration is a vital factor in exfoliators, a properly formulated exfoliator must contain the right pH (acidity) level as well. Overall, to have an impact, AHA’s and BHA’s need to be formulated with a pH between 3 and 4.

The skin has to convert AHA’s and BHA’s into free acids before it can be used. The conversion rate into free acids is contingent on the solution’s acidity. As such, a more acidic solution (lower pH) will create more free acids, which then can be used by skin.

Each type of acid has its own rate of conversion and the reasons why products are not made to be as acidic as possible is due to irritation. It’s a balance that needs to be struck because if the product is too acidic, it has a higher chance to irritate our skin.

Irritation When Using AHA or BHA

Irritated SkinYou’re prone to irritation when putting anything on your face, water included. Irritation becomes more prevalent when acids get involved. This is because people might not know how much to use when trying out high concentration products for the first time.

Any exfoliator should be gradually integrated into your regimen. Some people use layers of AHA and BHA several times a day. Others exfoliate a few times per week. Don’t rush into using it. See how your skin responds to it at first by using the exfoliator every other day or so.

Purging

Skin purging can happen when new to using any active ingredients due to the increase in skin cell turnover (like with AHA and BHA). As such, microcomedones, including pimples, which were already in the process of forming, are quickly ‘pushed’ to the surface. Generally, this can last for approximately 3 to 4 weeks. We advise sticking with your exfoliator for 4 to 6 weeks before determining if the product is the actual cause of the problem.

Photosensitivity (Light Sensitivity)

This is a common side effect of AHA. Dead skin acts as a sort of natural UV barrier, so when the skin’s top layers are exfoliated to reveal newer skin, skin becomes more sensitive. Because of that, we suggest using AHAs at night.

That’s not to say that you can’t use AHA in the day. If you’re using AHA’s during the daytime, we encourage the use of at least an SPF 30 sun protection product.

Using AHA and BHA at the Same Time?

While it’s not necessary to use AHA and BHA together, the use of both exfoliators simultaneously is common because the combination offers several benefits. If you have multiple concerns such as dull skin and acne; or if using just one type isn’t giving you the results you were expecting, then think about integrating both types into your regimen!

Closely monitor your skin when using both and adjust the frequency and use based on how your skin responds. Your skin will tell you if you’re over-exfoliating – if it’s red, inflamed, peeling, or flaking, then you know it’s time to scale things back a bit.

How to use AHA and BHA at the same time:

  1. Switch up their use in a day: AHA at night, BHA during the day
  2. Switch up their use each day - BHA on one day, AHA on the next
  3. Use them together - layer one product on top of another, AHA first, then BHA next


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