What is AHA? The Complete Guide to Alpha Hydroxy Acids
- Arya Kapoor
- 4 days ago
- 8 min read
Introduction: The Skincare Buzzword That Actually Works
If you’ve scrolled through skincaretok or been through a skincare aisle lately, you’ve probably seen three letters everywhere: AHA.
Some call them miracle exfoliants, others swear they ruined their skin which leaves many wondering - What exactly is AHA and should I use it or not?
AHAs (Alpha Hydroxy Acids) are dermatologist-backed exfoliants that smooth, brighten, and even out your skin tone when used correctly. But misuse them, and you’re looking at irritation, sensitivity, and a skin barrier screaming for help.
What Are AHAs?
AHAs or Alpha Hydroxy Acids are a group of water-soluble acids which are derived majorly from fruits but also from milk and sugarcane and these are chemical exfoliants.
So everyone who says - Chemicals are bad, don't put anything on your skin that nature didn't make, bla bla bla.... I think y'all should take some time to reflect on your knowledge. Because fun fact: everything - even water - is a chemical. The trick is knowing which ones your skin actually likes.
These highly potent and TOTALLY SAFE to use chemicals are considered better than physical scrubs which basically have microplastics in name of beads or even brushes as they work by dissolving the bonds holding dead skin cells together, so newer, healthier skin can surface.
Unlike BHAs (oil-soluble acids that dive into pores) or PHAs (gentler cousins with larger molecules), AHAs mainly act on the surface layer of skin.
That makes them especially useful for:
Dullness and uneven texture
Hyperpigmentation and acne marks
Fine lines and early aging
How does AHA work on skin? (The Science, Simplified)
Okay let's imagine that our skin is like ..... tiles. (Girl, you couldn't come up with a better example?) Over time, dirt and dead skin cells pile up, making the floor look dull and uneven. AHAs act like a safe cleaning solution, loosening the “glue” (desmosomes) that stick those dead cells together, because while the body is smart enough to shed the deadskin away, sometimes it just isn't FAST enough, hence testing our patience.
Once removed, fresh cells come to the surface. On a biological level, AHAs:
Increase cell turnover (your skin regenerates faster).
Boost hydration (especially with lactic acid, which is also a humectant).
Stimulate collagen production (with consistent use).
Refine texture (smoother, more even skin).
Image Courtesy : Protocol Lab
Types of AHAs (And Which One to Choose)
Not all AHAs are created equal. Each has its own strengths, so the “best” one depends on your skin type and concern.
1. Glycolic Acid (The Power Player)
Smallest molecule → penetrates fastest.
Best for: anti-aging, acne scars, uneven texture and majorly pigmentation.
One of the strongest soldiers in the exfoliant battalion but can be irritating for beginners.
Found in concentrations from 5–10% (serums/toners) to 20–70% (professional peels).
Read more in our [Glycolic Acid Guide]
While higher % of GA isn't commerically available for common public's usage, please don't try to get your hands on anything above 10% without consulting a dermat or worse...illegally! |
2. Lactic Acid (The Hydrator)
Gentler than glycolic and doubles as a hydrating agent.
Best for: sensitive or dry skin + people new to acids.
Naturally derived from milk, now lab-formulated for consistency.
Concentrations: 5–10% for daily products.
The Ordinary 10% Lactic acid + Hyaluronic acid serum
Read more in our [Lactic Acid Guide]
3. Mandelic Acid (The Gentle Multitasker)
Larger molecule = slower penetration, so less irritation.
Great for acne-prone skin and pigmentation issues.
Often paired with salicylic acid in anti-acne formulations.
Best is 5-10% for common use while professionals use 30-40% in chemical peels for post-acne scars in severe cases.
By Wishtrend 5% Mandelic Acid toner
Read more in our [Mandelic Acid Guide]
4. Malic Acid (The Team Player)
Found naturally in apples.
Mild exfoliation + antioxidant properties.
Usually combined with other AHAs for a “boost.”
Read more in our [Malic Acid Guide]
5. Citric & Tartaric Acids (The Extras)
Not usually the star of the show.
Found in small amounts in blends for pH adjustment and added antioxidant benefits.
Benefits and Side effects of using AHA on skin
See, everything has got pros and cons, and anything in moderation is fine (even great sometimes) but anything in excess can of course be harmful.
For example - Sugar! Which also reminds me that you need to REALLY get to know how sugar is harming your skin and how this isn't annnnother social media agenda.
Benefits of AHAs (Backed by Science)
The benefits of using AHA on skin are many. Dermatologists love skin and skin loves science and AHAs....are pure science.
Here’s what consistent AHA use can do for your skin:
Exfoliation → Radiance
If you have dull skin, AHAs should be on top your skincare shopping cart. They help in removing dead cells which gives you a smoother, brighter skin and the results are almost instant.
If you have whiteheads or blackheads, especially around your T-zone (your nose and forehead), considering using 5-7% Glycolic acid toner. In most of the cases that I have seen (including myself), the result is immediate. If you have sensitive skin, prefer lactic acid over glycolic or start with a smaller 2-3% twice to thrice a week at night time. Read more about how to use glycolic acid safely. |
Fade Pigmentation & Dark Spots
AHAs like glycolic and lactic acid are proven to lighten melasma and post-acne marks. While some skincare brands offer AHAs in the form of serums (and they work really good), you will also find the same at pharmacies in form of creams and emulsions that are just as effective. What matters is the percentage, the frequency of usage and of course - consistency!
Anti-Aging Benefits See, we know that AHAs work by breaking down the glue which holds the dead skin fibres, making it easier for our body to just shooo them off. This process triggers the production of newer skin cells and collagen production to maintain a smooth and firm skin, and we all know, the more the collagen, the less appearance of fine lines and wrinkles.
In a study conducted by Diana Tran et al, on the anti-ageing effects of AHAs of human skin, it was found that - "An antiaging skin care system containing AHAs and vitamins significantly improves the biomechanical parameters of the skin including wrinkles and skin texture, as well as elasticity without significant adverse effects." Source : Research Paper |
Improves Acne & Texture While BHA like salicylic acid is better for clogged pores, AHAs help resurface acne scars and prevent buildup.
Better Absorption of Skincare Products
Exfoliated skin = serums and moisturizers penetrate more effectively. Chemical exfoliants like AHAs, BHAs, and PHAs help by preventing buildup and breaking dead skin cells which allows your products to work exactly on their targets, giving you a better value for money (cuz let's be real, we girls especially end up spending a LOT of our hard-earned wealth over skincare bottles, we better be getting them results!!!).
Risks & Side Effects of AHAs
As I said above, everything used in excess...is harmful. So are AHAs. While they are highly effective and pretty safe, we must not forget that they are EXFOLIANTS and over-exfoliation ain't fun! Anybody who's had a bad history with over usage of physical exfoliants (though they are good), think how crazy chemical exfoliants can go.
Common issues with excessive usage of AHAs include:
Redness & irritation - Especially with glycolic acid, I am telling you again and again, it is HIGHLY potent which is why commercially max 10% GA in skincare is available to us
Purging - Temporary breakout as skin adjusts, if you are a beginner, start with lesser concentration and min. frequency.
Photosensitivity - AHAs make skin more vulnerable to UV damage, because they literally are removing the top layer skin cells, which makes it even more important for you to wear a sunscreen.
Safety Tips:
Start low: 5–10% concentrations.
Use 2–3x a week, then build up.
Always apply sunscreen during the day.
Avoid layering with retinol or strong Vitamin C in the same routine.
How to Use AHAs Correctly
Patch Test First → apply behind ear or jawline. Pss Pss... do you know the bad smell behind your ears is because of sebum. While sebum helps with keeping the area soft, moist, sometimes excess production or poor hygeine can cause buildup leading to a smell. Rub a cotton pad with glycolic acid toner sprayed over it. It works wonders & DON'T GATEKEEP!
Start with lower concentration such as 5% (it sounds small but honestly WORKS) with a frequency of 2-3 times per week.
Apply on clean, dry skin → before moisturizer. The rule of thumb when it comes to layering skincare is going thinnest to thickest in terms of consistency. Now you don't need a 20 whole step skincare routine but in case you are feeling fancy, here's how to layer skincare step by step based on their concentration. Now while it is recommended by the experts to use toner to prep your skin for whatever is coming next, in order to absorb it better, if you are beginner or you have sensitive skin, pat dry or air dry your skin first, skip the toner, use your exfoliant and follow up with a moisturiser to lock in everything as well heal your skin.
Pair with hydrating products (hyaluronic acid, ceramides). As mentioned above, when using any kind of exfoliant, make sure you follow up with hydrating agents (these days thanks to science that we have some amazing formulations where exfoliants are blended and balanced well with hydrating and moisturising ingredients). HA, ceramides, peptides help in maintaing water retention as well as healing your skin overnight.
Sunscreen daily (non-negotiable). Remember, photosensitivity? Yep! WEAR A SUNSCREEN.
Pro tip: If your skin stings for more than a minute or looks inflamed, you’re overdoing it. Don't fall for the tiktok scam that - IF IT BURNS, IT MEANS IT'S WORKING. No lady, if it burns, go wash your face! And if it still persists, depending on the level of pain, you have only 3 options - Aloevera, Grandma or a learned, licensed Doctor! |
AHA vs BHA vs PHA (Which One Do You Need?)
AHA: Best for surface-level concerns → pigmentation, dullness, fine lines.
BHA (Salicylic Acid): Oil-soluble → penetrates pores → best for acne, blackheads, oily skin.
PHA: Larger molecules, gentler action → best for sensitive skin beginners.
Full breakdown in our AHA vs BHA vs PHA comparison guide
Conclusion: The Takeaway on AHAs
AHAs are not hype — they’re science. Used right, they can transform dull, uneven skin into a brighter, smoother, more youthful version of itself. The key? Choosing the right acid for your skin type, starting slow, and never skipping sunscreen.
Next up in acid library :
[Glycolic Acid Guide] → anti-aging powerhouse
[Lactic Acid Guide] → hydration & glow
[Mandelic Acid Guide] → gentle acne fighter
[Malic Acid Guide] → the underrated antioxidant
And if you’re still confused between acids, don’t miss our [AHA vs BHA vs PHA breakdown].
FAQs (People Also Ask)
Q: Can I use AHA every day?
Not for beginners. Start with 2–3x/week. Daily use is only safe for low-concentration formulas.
Q: Is AHA safe during pregnancy?
Yes, lactic and glycolic acid in low concentrations are generally safe, but always check with your OBGYN and Dermatologist.
Q: Does AHA remove dark spots?
Yes, consistent use helps fade hyperpigmentation.
Q: Which is better: AHA or retinol?
They do different jobs - AHAs exfoliate, retinol boosts cell turnover and collagen. Basically exfoliants break and retin(als,ols,oids) build. So don't use them in the same routine. Read about the difference between retinal, retinol and retinoid.
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