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Your Guide to Understanding What Chemical Peels are in Skincare

Chemical Peels - Which is the Best For Your skin?

Beautiful skin and acid are an unusual combination. Generally, acids are feared for their corrosive properties. But trust the ingenuity of cosmetic scientists to harness this very property of acids to enhance your facial skin quality and looks! Certain acids such as AHA, BHA, TCA, and PHA have been found safe and effective in skin care and treatments such as chemical peels. There are hundreds of acid-based skincare products to help you look good and add to your confidence levels. 

What is more, today, chemical peels are widely used to treat various skin conditions. Superficial pigmentation, scarring, acne, rough texture, and uneven skin – you name it, and your aesthetic medical practitioner will probably have a solution for treating your specific condition. So, what exactly are these acids in your chemical peels and skincare products?  

Which of these are Better in  Chemical Peels

Some skincare products such as toners, lotions, and treatment products such as skin peels used in aesthetic procedures, use a special set of acids. These acids are clubbed under four categories - Alpha Hydroxy Acids (AHAs), Beta Hydroxy Acids (BHAs), Trichloroacetic Acid (TCA) and Polyhydroxy Acids (PHAs).

Several acids are used as the raw material for the multitude of skincare and treatment products that we use in our daily lives. While these acids are all essentially exfoliators, they vary in terms of their application for different skin issues. Usually, the lower the percentage of acid, the milder or less potent will be the formula.  

Alpha Hydroxy Acids (AHAs)   

A mainstay of daily skincare routines and chemical/medical skin peels. Alpha Hydroxy Acids (AHAs) are often found in the skincare serums, cleansers, toners, and creams that we regularly use. As chemical exfoliators, AHAs find extensive use in tackling oily skin and for treating blemishes. Typical examples of AHAs include glycolic acid and lactic acid. They literally gobble up the dead skin sediments on the skin surface. AHA products and AHA chemical peels are recommended for reducing wrinkles, uneven skin texture and epidermal pigmentation. If you feel a mild, prickly sensation when AHAs are applied to your skin, just relax. It is only the acids at work!  

Types of AHAs

  • Glycolic Acid
    Glycolic acid's small molecular structure allows it to penetrate deep into skin layers and do a thorough job of exfoliation. It can help your ageing facial skin regain its healthy glow. 
  • Lactic Acid
    Derived from milk, lactic acid is a relatively light chemical peel. It is ideal for treating sensitive skin types. It also has strong moisturising properties and works well on dry skin. 
  • Mandelic Acid
    Used widely for its anti-ageing properties. This acid helps clear away the surface-level dead skin and boost cell turnover in the skin. The increased cell turnover reveals a smoother and toned look. Mandelic acid also helps reduce fine lines and wrinkles on the face, especially when used as chemical peels.  
  • Citric Acid
    Apart from its exfoliating properties, citric acid also acts as a pH balancer. It is also brimming with antioxidants, making citric acid a favourite ingredient in skincare and treatments like facial skin peels. It helps reduce mild pimple scars, blemishes, and age spots. Its pH balancing properties help the skin to tackle the effects of sun exposure and pollution.

Beta Hydroxy Acids (BHAs)   

These are also a class of chemical exfoliators like AHAs. However, BHAs are used to treat different sets of skin problems. This class of acids is used in medical skin peels to treat oily or greasy skin problems, like pimples. This is because BHAs are oil-soluble; they can get through and under the oily layers that cover the skin and clog up your pores. Moreover, this class of acids possess antibacterial and anti-inflammatory properties. That is why you will find that this class of acids is especially handy when tackling skin conditions such as acne, milia, and blackheads. Due to their ability to penetrate the oily layers, BHAs can reduce the spots and redness that accompany these skin conditions. Salicylic acid is a good example of BHA and is used widely in acne treatments and products that rid facial skin spots.   

Types of BHAs

  • Salicylic Acid
    Strong on exfoliation as well as oil control, with high antibacterial and anti-inflammatory properties. This acid also helps control acne by targeting the bacteria responsible for infection and inflammation.   
  • Jessner's Solution

    This formulation comprises salicylic acid, lactic acid, and resorcinol. It is used to treat conditions ranging from epidermal hyperpigmentation to acne scars and wrinkles. It is a combination of AHA and BHA and therefore works on a range of skin conditions. While the salicylic acid disintegrates solidified skin cells in the epidermis, the lactic acid hydrates the skin, and resorcinol's antiseptic properties help sanitise the treatment zone. The peeling process begins after the solution is applied to the skin and remains undisturbed for six to eight hours without any water or oil. The peeling process unfolds over several days before it completes its course.

Trichloroacetic Acid (TCA) 

A derivative of acetic acid that is better known as vinegar, TCA is a non-toxic chemical agent used in chemical/medical peels for more than two decades. This peel is useful for treating skin conditions caused by ageing or sun exposure. Typically, TCA peels are a non-invasive approach for reducing superficial hyperpigmentation, fine lines, acne scars, discolourations, and improving skin tone. These peels are used for treating skin surfaces on the face, neck, décolleté, and limbs. They are also useful for 'spot improvement' of skin in specific areas of the body. 

Concentrations of TCA Chemical Peels

The concentration levels of TCA influence the extent of peeling depth. Apart from concentration levels, the volume and duration of the application also plays a role in the depth at which peeling occurs. For instance, peels with TCA concentrations below 20% effectively reduce fine lines and superficial wrinkles. While superficial or light chemical/medical peels contain TCA in concentrations ranging between 10% and 25%, medium peels use TCA in up to 35% concentration levels. TCA chemical peels with concentration levels ranging between 35 to 50% are used to treat the more intense conditions such as severe photo-ageing, epidermal hyperpigmentation, and solar keratosis.

How Do TCA Chemical Peels Work?

Superficial peels are effective on the stratum corneum or top layer of the skin. However, the efficacy of the more intense treatment modalities – medium peels – depends on the specific skin depths targeted in individual patients. The healing process usually lasts around a week after the TCA peel treatment. However, depending upon the dermal depth and time spent in TCA treatment, downtime can spread over a longer timeframe.  

TCA chemical peels procedures are customised according to the individual patient's skin condition and desired outcomes. Therefore, these specialised modalities are clinical procedures that are performed by trained and experienced practitioners only.

Poly Hydroxy Acids (PHAs)   

The fourth category of acids used in aesthetic skin procedures; Poly Hydroxy Acids (PHAs) is larger-sized molecule versions of the Alpha Hydroxy Acids. These acid categories work in much the same fashion – attack and loosen the "glue" binding the dead cells to the skin surface. But because of their larger molecular structures, the PHAs work at the superficial level – on the upper layers of skin.

The advantage of PHAs is that since they work entirely on the external layers of skin, the delicate inner layers remain intact. The bottom line is maximum skin renewal with minimum damage and irritation. PHAs are ideal for people who need skin treatments but are wary of stronger acid formulations. Even the most sensitive skin types can generally endure the treatments done with PHAs. Typical examples of this class of acids include tongue-twisters such as gluconolactone, galactose and lactobionic acid. 

Types of PHAs

  • Lactobionic Acid
    Commonly known as LA, this compound is a product of lactose oxidation in the human body. It is high in antioxidants and moisturising properties. Therefore, offers protection against pollution and harsh weather. Its large molecular structure keeps it safe for sensitive skin types.  
  • Galactose Acid
    Galactose is naturally present in our body as sugar converted by the liver to provide energy. It is used as an exfoliant in skincare treatments because of its prebiotic and antioxidant properties. Galactose Acid has large molecular structure. Hence, galactose acid is gentle on the skin. Therefore, it is ideal for treating sensitive skin, even if there are accompanying skin conditions like dermatitis and eczema.  
  • Gluconic Acid
    Besides exfoliation and cell renewal, gluconic acid helps regulate the keratinisation process. Its antioxidant and regenerative capabilities make it an ideal choice to treat damaged skin barriers. 

Comparison of Acids - AHA vs BHA vs PHA 

Alpha Hydroxy Acid (AHA) 

Beta Hydroxy Acid (BHA) 

Poly Hydroxy Acid (PHA) 


Small molecular size allows penetration to deeper skin layers. 

Larger molecular size compared to AHA making it a much gentler peel 

Relatively even bigger in molecular structure than BHA, which limits the penetration capabilities in the skin layers. 


  • Soluble in water
  • Derived from naturally occurring substances such as sugar cane, grapes, citrus fruit, almonds, and milk. 
  • Soluble in oil 
  • Act at the superficial and deeper layers as well of the skin.  
  • These acids decongest pores by disintegrating the sebum and dead skin cells that pile up. 
  • Soluble in water  
  • PHAs are gentle exfoliation peels that targets the superficial level of the skin 

  • They can cause less irritation and redness. 

  • Ideal for all skin types, but especially ideal for people with sensitive skin. 


  • AHAs start by peeling away the skin surface, to target roughness, and uneven skin texture. 
  • They also reduce wrinkles, enlarged pores, and signs of sun damage. 

  • Suitable for individuals with oily or combination skin. 
  • They targets whiteheads, blackheads, breakouts, and enlarged pores. 

  • These acids are also useful in reducing acne, spots, rosacea and inflamed skin. 

  • They clear away dead skin cells and excess debris from the surface, helping in gaining an even skin tone and texture.  
  • These acids  help to minimize pigmentation, fine lines, wrinkles, and acne scarring. 

  • They also keep the skin hydrated, boost cell renewal, and retain moisture. 

Types of acid peels 

  • Glycolic Acid 
  • Lactic Acid 

  • Mandelic Acid 

  • Citric Acid 

  • Salicylic Acid 
  • Jessner Peel Acid

  • Lactobionic Acid 
  • Galactose Acid 

  • Gluconic Acid 

As we can see, acids can treat and protect your facial skin effectively. But it is crucial to know which acids suit your skin type and can assure you of optimum results. Your doctor can help you gain a complete picture of AHAs, BHAs, TCAs and PHAs. Seek the proper treatment for your skin.