Acids 101: AHA, BHA, PHA


We’ve all heard catch phrases and marketing spills from various brands that echo in our heads something along these lines, “using AHA, BHA …. product will give your skin glow from sun……………… blah blah blah!”

This post is intended to provide you further information on source of these acids, their purpose in life, how it would benefit the skin and some product suggestions.


Operation Mode

AHA’s are water soluble which basically means it reacts with upper layer of epidermis and dissolves all dead skin cells on surface of skin. AHA’s operate at pH level of 3 – 5 (it’s the level of acidity, when compared to water at pH level 7 which is neutral).

Suitable Candidate or Skin Concerns

People experiencing sun damaged skin, aging, pigmentation, brown spots, wrinkles, rosacea, acne spots, congested skin.

Where should it be on the Ingredient list?

Products containing higher concentration of AHA’s would usually be listed 2nd – 3rd – 4th – 5th in the ingredient list (but these do not necessarily interpret effective result it may mean faster results).

Which acid is most effective? Which acid penetrates deepest in layers of skin?

It simply depends on the relevant acid’s Molecular size….Not all of the acids work in same way. Smaller molecules penetrate deeper in the skin for best results. But they are also the ones that give the skin tingling sensation or irritate very sensitive skins.

The following acids are in the order from . The following table shows the types of AHA’s, in the order of Smallest (deepest penetration in skin) to Largest molecule (more skin surface exfoliation), Source they are derived from, their Purpose in life and Product suggestions:

Type Source Derived from Function

Product Suggestions

Glycolic Acid

(Smallest Molecule)

Sugar Cane Degreasing and controlling production of sebum, and stimulate collagen production in skin. Alpha Hydrox range (12-14% Glycolic Acid)

Peter Roth Thomas Glycolic Range

Kate Somerville Glycolic & Retinol Peel

Alpha H Liquid Gold Range

Bravura London Glycolic Peel (10%) & Moisturizer (15%)

Lactic Acid Milk, Yoghurt, Sour Butter Milk or fermented fruit Antimicrobial, hydrating and adjusts ph level, skin softener, keeps skin moist Priori Gentle Facial Cleanser (13% Lactic Acid Complex)

Bravura London Lactic Acid Peel

Dermalogica Gentle Cream Exfoliant

Sunday Riley Good Genes

Malic Acid Apples, Cherry, Pears Hydrating, soothing and increases tissue respiration, increases oxygen supply to skin Dr Dennis Gross Alpha Beta Peel Packs

Juice Beauty Green Apple Peel

Tracie Martyn Amla Purifying Cleanser & Enzyme Exfoliant

Tartaric Acid Grapes, Berries, Currants, Passionfruit, Red Wine Antioxidant Arcona Raspberry Resurfacing Mask
Citric Acid Tomatoes, Oranges, Lemons (citrus fruits) Brightens skin, anti aging properties Mario Badescu Orange Tonic Mask

Ole Henriksen Truth Collagen Serum

Mandelic Acid Bitter Almonds Helps age spots, discoloration

Vivant Skincare Mandelic Serum

Dr Dennis Gross Ferulic + Retinol Brightening Solution


Operation Mode

BHA’s are lipid (oil) soluble, which basically means it can break down the oils on surface of skin and penetrate deeper in layers of skin. Due to the ability of BHA’s going deeper in skin, they aid in acting against sebum congestion under the skin’s surface. They have anti-inflammatory properties too. Like AHA’s, these operate at pH level of 3 – 5. BHA products may result in dryness and dehydration to the skin.

Suitable Candidate or Skin Concerns

BHA products are suitable for congested skin, blackheads, whiteheads, acne, wrinkles, and ingrown hair.

Where should it be on the Ingredient list?

Unlike AHA products, the products containing Salicylic acid would usually be listed towards end of the ingredient listing. BHA is far stronger and therefore effective on skin.

Type Source Derived from Function Product Suggestions

Salicylic Acid

(Molecule smaller than Glycolic Acid)

Salicylic Acid derived from White Willow Bark. Aspirin is also derived from White Willow Bark and its active ingredient is Salicylic acid. You may have heard Aspirin masks for acne prone skin. Unclog pores, helps with underlying congestion, ingrown hair.

NO impact on sebum production or killing bacteria.

Bravura London Salicylic Acid Peel 2%

La Roche Posay Effaclar Duo (French Version)

Skinceuticals LHA Solution (also has Lipo Hydroxy and Glycolic Acids)

Dr Dennis Gross Purifying Booster

Perfect Image Skincare – TCA (Trichloroacetic Acid) 15% Gel Peel Enhanced with Salicylic Acid

Body scrubs that contain Salicylic acid are brilliant for ingrown hair

Categories/Types of products that contain AHA’s and BHA’s

Cleanser, Toners, Exfoliators, Eye Creams, Serums, Moisturizers, Chemical Peels. Below I have summarized some of the products that contain AHA, BHA, or a combination of two. 

AHA & BHA General Knowledge

1) Most important thing to bear in mind is AHA and BHA do cause skin sensitivities especially to sun exposure. Basically all hard work done with skin care products, can be reversed with unprotected sun exposure or inadequate sun protection.

2)  Skin regeneration is turnover of new skin cells that is critical for healthy, radiant and clear skin. Whilst AHA’s, BHA’s and PHA’s are brilliant for chemical exfoliation which continually “promote” growth of collagen in skin, it should be noted that AHA, BHA, PHA don’t generate new collagen. These are a great prep point for repairing products that have specific ingredients aimed at repair and nourish various skin concerns.

3)  There are number of companies and products that have a combination of AHA and BHA (Salicylic Acid). As for AHA’s you will need to read the ingredient list to ensure which type of acid is included in the product. Some companies also used synthetically sourced AHA and BHA, which is not naturally sourced. Think of it as, Vanilla extract (in a bottle with alcohol) as against using natural vanilla pod! Similarly some companies use AHA concentrate rather than extracts from natural fruit or vegetable. 


For sensitive skins, that are irritated with deep penetration of Glycolic Acid or cannot handle the tingly sensation from AHA’s, the Poly Hydroxy Acids (PHA’s) come to their rescue.

Polyhydroxy acids enhance exfoliation of the outermost layer of the skin and normalize its thickness. Products containing PHA’s cause less irritation to sensitive skin due to their large molecular structures. Considering it has a larger molecular structure it doesn’t penetrate deep in layers of skin, however it has has been proven the efficacy is not impacted in anyway compared to any other AHA.

Generally, the two types of PHA’s available are Gluconolactone (from oxidized glucose – natural sugar found in human body) and Lactobionic acid (from oxidized lactose – milk sugar).

Some product suggestions with PHA’s:

Thanks for taking the time to read the post and hopefully it has answered some of your burning questions.




  1. You have no idea how helpful this post is! I’m bookmarking it!
    I use Lotion P50 everyday and Good Genes once a week. Just from the perspective of having a well rounded routine, I don’t use any product with glycolic acid, but should I?

    Advaita | Blush Canvas

  2. I’ve never commented on a single blog post before but this one is beyond helpful for those of us who want to take care of their skin but feel overwhelmed by the jargon. Thanks you so so much!

  3. This is such a helpful post! I keep seeing the words AHA and BHA thrown around skincare and I honestly had no idea what they all did. I’m bookmarking this for future reference just in case haha!

    Lindsey Elyse | lindseyginge

  4. I’ve been using Neostrata products for 35+ years. The glycolic acid keeps my face clear, radiant, and no lines. I use aha and pha. My face is sensitive and the products do tingle but you know it’s working. It makes my face red sometimes but it exfoliates and keeps my face firm and brightens my skin. I order from amazons where it’s the cheapest I’ve found. It lasts forever and you only use a little bit. There are lotions and gels. These products work. They have 8% up to 20%. You have to use sun screen after using. Worth the money. Better than anything in the department stores. They used to be only sold at dermatologists.

    1. Wowww that’s a long time you’ve been using aha. Neostrata almost seems like veteran on aha. It was one of my first foray into acids too and my skin saw immediate improvement. Thank you for taking the time to read and comment xx

  5. This saved my life literally thank you so much
    In addition to this I was also wondering what you would recommend for uneven skin tone bearing in mind im only 15

    1. I’m very glad this post helped you. Aaisha you’re very young to adopt strong aha or bha unless you’re breaking out. For uneven skin tone I’d say make sure you have proper sunscreen and sun protection hat or clothing. At a minimum have a solid cleanser, toner and moisturiser. That’s all teenage skin needs with proper sun care. In about 5 or so years, you can start making your skincare routine more robust. Hope this helps xx

  6. What a wonderful post! It’s obvious that you love skincare as you’re so thorough and informative. Thank you!
    Just wondering if you know anything about long term side effects? Is there such a thing as too much of a good thing?


    1. Well as with anything too much acid or excessively done may thin out your skin barrier, using acids without appropriate sun protection may do more damage. Balancing the use of acid with more hydrating, nourishing and replenishing products is crucial.

  7. Im new to skincare and my first chem exfoliators are cosrx’s aha and bha power liquid. Both made me break out at first and then i just used the bha one around my nose and inner cheek area and its fine. I use the aha for the rest of my face and i still break out from it a lil bit only on my cheeks (i get tiny whiteheads). Im a college student so i cant afford to buy expensive ones but it seems that this brand’s chemical peels didnt work out for me. Im thinking of finishing the ones i have now and switching to bravura but im afraid that ill just have the same result. Do you have any suggestions? :”(

    1. Hi Kirsten, thank you for taking the time to read. I havent tried Cosrx toners so wouldn’t be able to compare them with any others. However I’ve used Bravura London for 3ish years now and keep going back to it. Given that you’re breaking out to the acid, may be you’re skin is asking for more or something else in addition to the acid. Ensure skin is properly hydrated and moisturized too. Oils are balanced in skin.

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