Our skin has the ability to remove dead cells through a natural exfoliation process. However, as we age, this ability diminishes and can even stop entirely. Without exfoliation, the complexion becomes dull, dry, and flaky, enlarged pores appear, wrinkles form, and the skin loses firmness and an even tone. That's where AHA and BHA chemical exfoliants make a remarkable difference through their ability to remove dead cells from the skin's surface and restore a healthy, radiant complexion. If you want to learn what AHA and BHA are, what a chemical peel is, what the difference between them is, how to use them in your skincare routine, and which one is best suited for your skin type, keep reading this article with detailed information about chemical exfoliants.
The importance of exfoliation: why choose chemical exfoliants?
The skin naturally sheds dead cells, but this process slows down especially after the age of 30 or during stressful periods. The result: radiance fades, blackheads or dry patches appear, and uneven textures and spots seem harder to get rid of. Chemical exfoliants like AHA and BHA speed up this process, so the skin looks cleaner, smoother, and more even-toned.
What benefits does proper use of exfoliants bring?
- Reduces the appearance of blackheads and spots;
- Evens out skin colour and fades pigmentation marks;
- Smooths skin texture;
- Prevents pore blockage and reduces excess sebum if you have oily skin;
- Brightens the overall appearance of your face.
If you'd like a detailed guide on how to correctly introduce exfoliation into your routine and what mistakes to avoid, you'll find details here: facial exfoliation, steps and recommendations.
What exactly are AHA and BHA?
AHA (alpha hydroxy acids) and BHA (beta hydroxy acids) are two types of hydroxy acids that support the skin's natural exfoliation process. These two types of acids are designed to address various skin concerns. Their ingredients help with cell renewal, delivering smoother skin with an even tone. The benefits of exfoliating acids were discovered in ancient times — in ancient Egypt, Cleopatra used to bathe in sour milk to improve the appearance of her skin. Today, chemical exfoliants can be found in skincare products such as facial cleansers, body exfoliants (for example, AHA EXFOLIATOR SCRUB), serums, body lotions, toners (such as AHA 3% SCALING), and many more.
AHA and BHA acids belong to the category of chemical exfoliants — ingredients that remove dead cells without the need to rub or scratch the skin, as is the case with mechanical exfoliants.
Before detailing each acid, here are the key facts about their role in skincare:
- AHA and BHA are chemical exfoliants that help gently remove dead skin cells through a facial peel;
- Chemical exfoliation differs from physical exfoliation, which uses physical objects such as scrub-type exfoliants (with exfoliating particles) to manually remove dead skin cells. Physical exfoliation is often not as gentle on the skin as chemical exfoliation;
- The role of alpha hydroxy acids is to help smooth and soften the skin, as well as reduce the appearance of fine lines and wrinkles;
- Beta hydroxy acids are beneficial for treating rough, bumpy skin, imperfections caused by acne, as well as psoriasis.
What is AHA?
Alpha hydroxy acids are a type of exfoliating acid. They are naturally found in sugar cane (glycolic acid), milk (lactic acid), and fruit sources (citric acid). For the cosmetic formulas used today, alpha hydroxy acids are usually produced in a laboratory.
Alpha hydroxy acids are increasingly sought after in skincare routines due to their ability to reduce signs of skin ageing such as fine lines and wrinkles, prevent sun-induced ageing, and address discolouration. This type of acid is considered safe for skin and can be used to gently remove dead cells, helping to improve the overall appearance and texture of the skin.
What is BHA?
BHA are another category of exfoliating acids known as beta hydroxy acids. They are used for many skin concerns, such as rough and blemish-prone skin, acne, psoriasis, seborrhoeic dermatitis, and more. Similar to AHA, BHAs are naturally found in many plant-based sources but are most often created in a laboratory when included in cosmetic products.
What are the main differences between AHA and BHA?
Although all hydroxy acids share some similarities, there is a major difference between them. While both AHAs and BHAs act as skin exfoliants, AHAs are what is known as "water-soluble", while BHAs are considered "oil-soluble". This means that AHA acts on the skin's surface, while BHA (such as salicylic acid) works both on the surface and inside the pores. For this reason, salicylic acid is recommended for acne-prone skin, working on clogged pores and reducing uneven skin texture. AHA (such as glycolic acid) focuses on reducing fine lines, wrinkles, and signs of sun damage.
It's important to understand exactly how they differ before choosing the right product.
Brief definitions and basic differences
- AHA (alpha hydroxy acids): acids that dissolve in water and act on the skin's surface. Glycolic, lactic, citric, and mandelic are examples of AHA. You'll usually find them in serums, masks, or exfoliating creams, with an optimal skin pH between 3 and 4;
- BHA (beta hydroxy acids): oil-soluble, which helps them penetrate deeper into the pores. Salicylic acid is the main representative of this category and is noteworthy for its benefits for combination, oily, or blemish-prone skin.
AHA and BHA acids can come from natural sources or be obtained through synthesis. The source doesn't necessarily matter — what counts is compatibility with your skin's needs.
| Criterion | AHA (alpha hydroxy acids) | BHA (beta hydroxy acids) |
|---|---|---|
| Solubility | Water-soluble | Oil-soluble |
| Area of action | Skin surface | Surface + deep within pores |
| Suited skin type | Dry, dehydrated, sensitive, mature | Combination, oily, acne-prone, enlarged pores |
| Primary effect | Exfoliation, hydration, evening out | Pore cleansing, sebum regulation, acne reduction |
| Example acid | Glycolic, lactic, citric, mandelic | Salicylic |
| Advantages | Smooths, stimulates collagen, hydrates | Reduces breakouts, soothes skin |
| Possible drawbacks | May cause irritation or sun sensitivity | May dry out or irritate, especially dry skin |
Recommendation by skin type
- Choose AHA if your skin feels dry, you have pigmentation marks, or you want to reduce fine lines.
- Opt for BHA if you deal with blackheads, acne, or excess sebum.
Example: someone with combination skin who has dry areas and areas with blemishes can use AHA on the cheeks and BHA in the T-zone (forehead, nose, chin).
The most popular types of AHA and BHA and what each one does
Types of AHA
Although there are several different types of AHA, the most commonly used alpha hydroxy acids you'll find in cosmetic products are lactic acid and glycolic acid. Sometimes, these two types can be combined for their multifunctional benefits, such as in the AHA 6% peeling gel by dr. Hedison, which combines both types of AHA (3% lactic acid and 3% glycolic acid) for deep exfoliation while maintaining optimal skin hydration.
The types of AHA are:
- Lactic acid: Derived from milk, it has a moisturising effect. Many people tolerate it well, including those with sensitive skin.
- Glycolic acid: Derived from sugar cane, it has a small molecule and acts quickly. It's suited for mature skin, fine lines, and visible pigmentation marks.
- Citric acid: Extracted from citrus fruits; it brightens skin and evens out complexion tone.
- Mandelic acid: Larger molecule, so it penetrates slowly and the risk of irritation decreases. Consider this acid if you have reactive skin.
Lactic acid
Lactic acid is a common AHA used in skincare exfoliation products that remove dead skin cells. This gives the complexion smoothness, softness, and improved texture when used regularly in a skincare routine. Lactic acid is also part of the skin's natural moisturising factor, which can help the skin retain moisture.
Glycolic acid
Glycolic acid is another of the most frequently used AHAs in skincare. This exfoliating acid has the lowest molecular weight of all alpha hydroxy acids, allowing it to penetrate the skin easily and efficiently. To enjoy the benefits of this ingredient, you can try the super-hydrating GLYCOLIC ACID DAILY TONER Q+A, which balances hydration levels, offering multiple skin benefits and restoring radiance.
Citric acid
Citric acid is an AHA derived from citrus fruits and is valued for its ability to brighten and revitalise the skin. It helps gently remove dead cells, contributing to evening out the complexion tone and reducing dullness. Citric acid also has antioxidant properties, supporting the skin's protection against external factors and adding freshness and radiance to the skincare routine.
Mandelic acid
Mandelic acid is an alpha hydroxy acid with a larger molecule, meaning it penetrates the skin more slowly and has a lower potential to cause irritation. It's a suitable choice for those with sensitive or reactive skin, as well as for those dealing with imperfections or pigmentation marks. Through gentle exfoliation, mandelic acid helps improve skin texture and achieve a more even, smoother appearance.
Lactic acid
Beyond its exfoliating properties, lactic acid is recognised for its moisturising effect, as it is part of the skin's natural moisturising factor. It supports maintaining optimal moisture levels, contributing to a more supple and velvety complexion. Due to its good tolerability, it is often recommended even for sensitive skin, providing an efficient balance between exfoliation and hydration.
Salicylic acid, a BHA acid
BHA acids are valued in skincare routines for the way they work in depth and for the benefits they bring to skin prone to excess sebum, enlarged pores, or imperfections.
Salicylic acid is the best-known and most widely used, ideal for cleaning pores and reducing imperfections. You'll find it in many forms, including acne-prone skin care products or cleansing formulas like the salicylic acid cleanser;
Found naturally in the bark of certain plants — such as white willow and wintergreen leaves — salicylic acid is a beta hydroxy acid commonly used for its gentle yet effective exfoliating properties. Among the beneficial effects of salicylic acid are: reducing inflammation, swelling, and redness, reducing the appearance of enlarged pores, deep-cleansing them, removing dead cells and excess sebum, contributing to cell regeneration and diminishing wrinkles, fine lines, or superficial scars.
However, salicylic acid must be used in an appropriate concentration, as it can irritate the skin.
Salicylic acid is found in numerous cosmetic products, such as cleansers, toners, lotions, serums, as well as body care products. If you deal with issues like body blemishes or even acne, you can try SALICYLIC ACID SMOOTHING LOTION, which exfoliates the skin, removes dead cells, and prevents new blemishes. It also soothes irritated skin, deeply hydrates, and reduces excess sebum.
Can AHA and BHA be used together?
AHA/BHA can be used together when included in specially formulated products; however, alternating them is generally recommended. While most people choose to use just one, there's nothing wrong with using both or experimenting to see which works best for you. The important thing is to test how your skin reacts to each. Based on the response, you can choose to continue with both or just your preferred one. Keep in mind that both can cause irritation, especially when not used in the right concentrations or not applied correctly.
Used together, AHA and BHA can deliver remarkable results if you're dealing with multiple skin concerns (such as sun damage, deep wrinkles, clogged pores, puffiness, dull complexion, flaky skin). In fact, alternating AHA and BHA exfoliants is considered the perfect solution for addressing all skin concerns.
How to integrate AHA and BHA into your skincare routine
Ideally, use AHA and BHA alternately. For example, AHA one day, BHA another. They can be used in the same routine in specially formulated products, but alternating is generally recommended.
Apply the AHA/BHA exfoliant after the cleansing and toner steps. For the best effect, the skin needs to be thoroughly cleansed of impurities, and the toner helps regulate pH.
You can achieve better results and avoid unpleasant reactions by applying the acids in steps suited to your skin.
The right time for chemical exfoliants:
- Apply AHA preferably in the evening. These acids increase light sensitivity.
- You can use BHA both morning and evening, but don't forget to use sun protection if you prefer the morning.
Application order:
- Start with make-up removal and cleansing;
- Continue with the chosen exfoliant (serum, toner, mask) on clean skin;
- Apply your next hydrating products, serums, or creams;
- In the morning, always use sun protection (SPF 30+).
Example routine
- For dry or sensitive skin: opt for lactic or mandelic acid. Apply once every two to three days, in the evening only. Avoid other potentially irritating products (e.g. retinoids, vitamin C) in the same routine;
- For oily or combination skin: use salicylic acid two to three times per week. Monitor your skin's reaction, and if you see good results, you can gradually increase the frequency;
- For mature skin: glycolic acid, applied regularly, can reduce fine lines and add radiance.
Frequency and alternation
- Start with 1–2 applications per week;
- Increase the number of sessions over time if the skin tolerates it well;
- Don't combine AHA and BHA on the same day at first; alternate them to see how your skin reacts. For example, use AHA on Monday and BHA on Thursday.
How to alternate exfoliants:
A gentle chemical exfoliation once a day, morning or evening, depending on personal preference.
If you want to alternate AHA and BHA, you could choose one for a week, then switch to the other the following week.
Once or twice a week, introduce a higher-concentration AHA or BHA treatment into your routine for impressive results.
Remember, when using these ingredients, you must always apply sun protection, regardless of the season.
AHA and BHA are extremely beneficial acids for skin health, offering multiple advantages for different skin concerns. If you want a radiant complexion free of visible wrinkles, enlarged pores, and imperfections, with an even tone, then AHA and BHA are the answer to all your skin concerns.
Choosing the product and examples
You can try lightweight liquid exfoliants, serums, or dedicated toner-type products, depending on how familiar you are with this type of skincare. Browse this exfoliants collection for inspiration.
Precautions and practical recommendations for using AHA and BHA
Chemical acids are part of an effective routine but come with certain conditions to stay safe.
What to follow to avoid irritation and achieve visible results:
- Protect your skin with a high SPF (minimum 30), regardless of the season;
- Don't use chemical exfoliants combined with other irritating products (mechanical scrubs, retinoids, excess alcohol).
- If you feel stinging, persistent redness, flaking, or new breakouts appear, stop applying and seek a dermatologist's advice.
- Avoid application on damaged, irritated skin or if you have conditions like rosacea or eczema.
- Adjust the concentration and frequency if unpleasant reactions occur — occasionally, even a single use per week may be enough.
Frequently asked questions about chemical exfoliation
What are AHA and BHA acids and how do they work in skincare?
AHA (Alpha Hydroxy Acids) and BHA (Beta Hydroxy Acids) are two types of chemical exfoliants used in skincare products. These acids provide a facial peel by removing dead cells from the skin's surface, thus promoting cell regeneration and improving the texture and radiance of the complexion.
What AHA concentration is beneficial for skin?
AHA concentration in skincare products can range from 5% to 30%, but the recommended concentration for beginners is generally between 5% and 10%. To achieve visible benefits and minimise the risk of irritation, it's important to start with a lower concentration and gradually increase as your skin adapts.
What BHA concentration is beneficial for skin?
BHA concentration used in skincare products typically ranges between 1% and 2%. This concentration is sufficient to provide exfoliation benefits and help clean pores without excessively irritating or sensitising the skin.
Why must I use sunscreen when using AHA and BHA?
Using AHA and BHA can make the skin more sensitive to the harmful effects of ultraviolet radiation, which may increase the risk of sunburn. Therefore, it's essential to apply sunscreen with an adequate SPF every morning, even on cloudy days or when you don't spend much time outdoors. This will protect the skin against the harmful effects of sun rays and prevent premature signs of ageing, such as pigmentation marks and wrinkles.
How do I know if the exfoliant suits me?
Test it on a small area of skin (for example, the jawline) before applying it to the entire face. If no reactions appear within 24 hours, gradually increase the area of application.
Can I use chemical exfoliants during pregnancy or breastfeeding?
Talk to your doctor. Certain concentrations and types of acids are recommended to be avoided during these periods.
Can chemical exfoliants be paired with other popular skincare ingredients (collagen, peptides, PDRN)?
Yes, but apply them in separate steps of your routine and pay attention to how your skin reacts. Many formulas containing collagen or peptides help soothe and regenerate after exfoliation, but avoid accumulating irritants.
Adapting your routine to the season and the right product
During summer, pay extra attention to sun protection. Exfoliated skin reacts more quickly to UV rays, and the risk of pigmentation marks increases without adequate protection.
Alongside acids, you can complement your routine with lightweight moisturisers or creams containing soothing ingredients (e.g. allantoin, centella asiatica). In the warm season, choose gentle exfoliation (for example, lactic or mandelic acid applied every 3–4 days).
If you explore Korean products or established skincare brands, you'll discover plenty of options adapted to various needs. This guide remains valid regardless of which range you purchase your exfoliants from, prioritising your skin type.
How to choose between AHA and BHA
- Analyse your skin's main concern: dryness, spots, uneven texture – choose AHA. Congested pores, shine, frequent blemishes – try BHA;
- Consider the season and your personal tolerance;
- Don't rush results; take it step by step and adapt your routine based on your skin's reaction;
- Browse the range of skincare products suited to your skin type.
Conclusion
Responsible use of AHA and BHA acids helps maintain a healthy complexion with a fresh, well-cared-for appearance. Whatever your choice, start with low concentrations, follow the recommended frequency, and make sure to include daily sun protection. For any unusual reaction or if you have pre-existing medical conditions, seek a dermatologist's advice.
Take care of your skin! Discover the products that meet your needs on SKINSEEN.ro and try introducing chemical exfoliants with patience and knowledge!
Disclaimer: This article is for informational purposes only and does not replace specialist medical advice. Always follow your doctor's recommendations, especially if you have skin conditions or are undergoing dermatological treatment.
