We’ve all heard of acids such as glycolic acids, and if you’re acne prone- salicylic acid and the rest. These acids are used in skincare products as chemical exfoliants i.e they help to chemically detach cells in the upper most layer of the skin from one another, yielding a more youthful, smoother, brighter skin.

What are the various types of acids used in skincare ?

How do they work?

Lower strength acids as found in OTC cosmetics (usually <10%) works at the level of the epidermis specifically at the stratum corneum (upper most layer of skin) and causes exfoliation.

Higher strength acids (>20%) are used as in-office procedures by professionals as chemical peels. Higher strength and lower molecular size acids such as glycolic acid can penetrate deep into the skin (upto the dermis) to boost collagen, GAG’s production thereby increasing the thickness of skin, and reversing signs of photoageing such as wrinkles, deep lines, sun spots etc.

Concept behind exfoliation

As we age our skin cell turn over (cells from the lower layer, divide and mature and are eventually shed off) slows down. As a results more cells from the startum corneum accumulate on the surface which gives aged skin a more dull, and rough appearance. Chemical exfoliation using acids helps speed up the process of shedding the upper layers of the skin. Hence, incorporating acids in our skin care are of benefit a we age and and for addressing certain skin concerns. They are un-necessary for younger age groups as their skin can naturally exfoliate at a good rate.

Acids beyond exfoliation

Uses of acids in skin care products can be more than just for exfoliation. Different acids have a slightly unique properties that help address specific concerns.

How to choose a chemical exfoliant?

Firstly, not everyone needs a chemical exfoliant in their routine. If you do not have any skin concerns, or if you are happy if your existing routine, continue what works for you regardless of whether you have such acids or not in your routine.

Amongst AHAs : 

1. Glycolic acid is most commonly used and widely available in skincare products. However being of smaller molecular size, it can penetrate the deeper layers of the skin and cause irritation for some. 
2. Lactic acid: another common AHA, but has additional properties of being able to retain water thus hydrating the skin. It’s also less irritating as compared to GA 
3. Mandelic acid : a larger molecular weight AHA that is great for people not tolerating other acids or for people with sensitive skin as it is least irritating. 

PHA and PBHAs, the newer generation acids. Not only do they provide gentle chemical exfoliation, some PBHAs such as lactonionic acid help hydrate and soothe the skin. 

Note: The tolerability of such acids are also dependent on the overall formulations. Some products have a combination of these acids for maximum benefit and least irritation. Most often you only require a single product, and try not to use too many chemical exfoliants in your skin care routine without a professional consultation. 

What can go wrong with such products?

Irritation is the most common side effect of using such products. It can present as redness, burning or itching. It can also be seen as bumps resembling acne. Start by using such products just once-twice a week instead of every night and do not forget your sunscreen.

Some people may be allergic to certain acids, always perform a patch test prior to using such products especially if you have sensitive skin.

Over exfoliation can disrupt your skin barrier, making it sensitive, dry and irritated. In this case, stop using such chemical exfoliants and jut stick to the basics: cleanser, moisturiser and sunscreen.

If you already have a routine for your acne or pigmentation, please consult your dermatologist prior to incorporating such products in your routine.