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Skincare acid guide. AHA vs BHA vs PHA. The best skincare acid exfoliation for your skin type.

Updated: Jul 28, 2020

Why should we use acid exfoliant skincare products? Are all the acids the same? Do you know the difference between skincare acid exfoliant and how to choose one right for your skin type? AHA vs BHA?

skincare acid exfoliant droplet

We are all very familiar with skincare acids such as AHA vs BHA and PHA and their benefits by now. Are we using the right acid for our skin type and condition? AHA vs BHA and PHA on a basic level, exfoliate your skin and reveal fresher skin cells making our complexion looks brighter.

However, there are many differences between these acids and knowing the differences and choosing the right acid will provide better skin health and results.


3 key factors when choosing acid exfoliation products:

Types of skincare exfoliant acid. what to look out for when buying? Information of acid types, concerntration and PH levels.

For example: if you buy 2 products, both with 10% glycolic acid:

One with PH level 3, the free acid percentage is 8.71%.

Other with PH level 5, the free acid percentage is 0.63%


As you can see, the PH level significantly changes the efficiency of glycolic acid. By dropping 2 PH levels, the acid is suddenly many times more potent.


Knowing these factors, you can then choose how you would implement acid exfoliant into your routine.

1. A gentle daily exfoliant

2. A weekly exfoliant


AHA - Alpha Hydroxy Acid


Alpha Hydroxy Acid is a group of natural or synthetic actives which exfoliates your skin. AHA can be formulated into different concentrations to provide various strengths of exfoliations. This can varies from gentle daily exfoliant to weekly exfoliant to an intensive dermatologist peel.


PHA - Polyhydroxy Acid


Polyhydroxy acid is the next generation of AHA. PHA provides the same exfoliating properties but is gentler than AH due to their larger molecular size. PHA works on the surface and does not penetrate as deeply as AHA (acids and formulation dependant).


BHA - Beta Hydroxy Acid


Beta Hydroxy acid is an oil soluble acid. Being oil soluble means BHA can penetrates oil film on your skin and clearing pores. BHA is best for oilier and acne prone skin.


What do these acids do?


AHA, BHA and PHA are all exfoliants. They work by melting the intercellular glue which holds the skin cells together. Using these acids will accelerate the cell turnover rate revealing fresher skin cells.


Why do we need chemical exfoliation when our skin turns over itself?


During our 20’s, our skin cells turnover every 28 days. As you age, your skin cells turnover rates slow (up to every 45 days), you may need the helping hand to exfoliate dead skin bringing fresher skin cells to the surface. These younger cells hold water better and allow the moisturiser to penetrate better.


Apart from exfoliation, Acid can:

1. Reduce wrinkles and fine lines.

2. Boost collagen

3. Help reduces pigmentation

4. Treat acne


What is the difference between the acids? How do you choose the right acid?


Here is a list of common AHAs in respective to their molecular sizes (Glycolic acid being the smallest). The smaller the molecular size, the stronger exfoliating effect it has on the skin.


Types of AHAs (Alpha Hydroxy Acid)

 Types of AHAs (Alpha Hydroxy Acid), the pros, cons and what to watch out for when using these skincare exfoliating acids.

BHA (Beta Hydroxy Acid)

BHA (Beta Hydroxy Acid) salicylic acid, the pros, the cons and what to watch out when using Salicylic acid
BHA (Beta Hydroxy Acid) Salicylic acid

Types of PHAs (Polyhydroxy acid)

Types of PHAs (Polyhydroxy acid) the pros, cons and what to watch out when using Types of PHAs (Polyhydroxy acid)

Which acid exfoliant is best for your skintype?

Types of acid for different skin types

This indicates acid best for selected skin types. This is not to say that you cannot use other acids which are not indicated but to show whcih acids works best for different skin types. This is strictly based on acid type. Acid concentration and PH are taken into consideration in this table.


What works with Acid and what doesn’t?


Acids' compatibility with other skincare ingredients

Acids' compatibility with other skincare ingredients. niacinamide, ceramindes, sqaluene, retinoids, vitamin c

* We recommend using a formulation containing both acids and not mixing single ingredient product/ acids in your routine as they are harder to control.


When and how should you use an acid exfoliant?

Once you determined how you would like your exfoliating acid to perform in your routine, you can decide when and how to use it.


As a gentle daily exfoliant,

1. Choose a lower concentration acid (which suits your skin type)

2. A low PH formulation (between 3 to 4)

3. If you are new to acid exfoliant, start off with 3 times weekly in the evening. Increase or decrease frequency depending on your skin’s reaction.

As a weekly exfoliant,

1. Choose a higher concentration (which suits your skin type)

2. A low PH formulation (between 3 to 4)

3. Use once weekly in the evening


Using exfoliant acid nightly is fine if you are not using retinol. What if you are using retinol in the evening?

In that case, either

1) Use your acid exfoliant in your morning routine. Some people do not like this due to sun exposure during the day.

2) Use your acid exfoliant and retinol on alternate evenings, never on the same evening especially if you have sensitive skin.


Use of exfoliant acids increases skin sensitivity