Quick answer: AHAs exfoliate on the surface and suit dry or pigmented skin. BHAs go into the pore and suit oily or acne-prone skin. PHAs are the gentlest option and suit sensitive or reactive skin. On Indian skin, sun protection the morning after any chemical exfoliant is not optional. It is what separates a good result from a hyperpigmentation flare.
Every few months, a new serum makes its way into Indian skincare conversations. Glycolic acid, salicylic acid, lactic acid, mandelic acid, gluconolactone. The ingredient lists are getting longer and the marketing is getting more confident. If you have tried a few of these products and found that your skin reacted badly or simply saw no change, the most likely reason is not that the ingredient does not work. It is that the wrong type was matched to the wrong skin.
This post explains the clinical difference between AHAs, BHAs, and PHAs, what each one does inside the skin, and how to choose the right one for your specific concern. The information is written for Indian skin types, because Fitzpatrick IV to VI skin, which covers most patients across Kerala and Tamil Nadu, has specific characteristics that change how these ingredients behave.
Written by Dr. Sarath Chandran, MD DVL, IADVL-registered dermatologist and Managing Director, DermaVue Clinics.
Table of Contents
- What Is a Chemical Exfoliant
- AHAs: Alpha-Hydroxy Acids
- BHAs: Beta-Hydroxy Acids
- PHAs: Polyhydroxy Acids
- Comparison Table: AHA vs BHA vs PHA
- Why Indian Skin Needs Extra Caution
- Common Mistakes Dermatologists See
- How to Introduce a Chemical Exfoliant Safely
- When to See a Dermatologist
- Chemical Exfoliant Assessment at DermaVue
- Recommended Viewing
- Frequently Asked Questions
What Is a Chemical Exfoliant and What Is It Actually Doing
Physical exfoliants use friction. Scrubs, loofahs, brushes. They manually buff away dead skin cells from the surface.
Chemical exfoliants use acids or similar compounds to dissolve the bonds holding dead skin cells together. Instead of scrubbing the cells away, the acid breaks the attachment between them and the layers beneath, allowing the cells to shed more evenly and reveal the newer skin underneath.
The difference matters because friction-based exfoliation can cause micro-tears in darker skin tones and is more likely to worsen pigmentation through mechanical irritation. Chemical exfoliation, when done correctly, tends to produce a more even result on Indian skin. When done incorrectly, it can cause significant irritation, redness, and the very pigmentation it was meant to address.
The three main categories of chemical exfoliants used in skincare today are AHAs (alpha-hydroxy acids), BHAs (beta-hydroxy acids), and PHAs (polyhydroxy acids). Each category works by a different mechanism, at a different depth, and for a different set of skin concerns.
AHAs: Alpha-Hydroxy Acids
What they are
The most common AHAs in skincare products are glycolic acid, lactic acid, and mandelic acid. Citric acid and tartaric acid also fall into this category but are less commonly used as primary exfoliants.
How they work
AHAs are water-soluble. They work on the outermost layers of the skin by breaking the bonds between dead skin cells and the surface below them. Glycolic acid has the smallest molecular size of all AHAs, which means it penetrates the most quickly and works the most aggressively. Lactic acid has a larger molecular size and penetrates more slowly. Mandelic acid is larger still and is the most gentle of the three.
Aside from exfoliation, AHAs at higher concentrations also stimulate collagen production. The US-FDA has published guidance on alpha-hydroxy acids in cosmetics confirming their established safety profile at OTC concentrations. Dermatologist-administered AHA peels at concentrations of 30 to 70 percent are used for texture, fine lines, and scarring. Over-the-counter products typically use concentrations of 5 to 15 percent for daily or weekly use.
What AHAs are good for
- Dry or dehydrated skin that looks dull
- Uneven skin tone and surface pigmentation (post-inflammatory hyperpigmentation, sun spots)
- Fine lines and texture concerns
- Mild acne scarring on the surface (for deeper scarring, see acne scar treatment at DermaVue)
- Skin that needs general brightening
Which AHA suits Indian skin best
For most Indian patients starting with AHAs for the first time, lactic acid or mandelic acid is the better starting point than glycolic acid. Indian skin has higher levels of melanin. Melanin-producing cells (melanocytes) in darker skin tones are more reactive. When the skin experiences irritation, even mild irritation from an acid that is too strong or used too frequently, those melanocytes can overproduce pigment as a protective response. This is post-inflammatory hyperpigmentation, and it is far more common and more persistent in Fitzpatrick IV to VI skin than in lighter skin types.
Mandelic acid is particularly well-studied for Indian skin. Its larger molecular size means slower penetration, less irritation, and a more gradual exfoliating effect. It also has mild antibacterial properties that benefit acne-prone skin.
BHAs: Beta-Hydroxy Acids
What they are
Salicylic acid is the primary BHA used in skincare. It is derived from willow bark and has been used in dermatology for over a century. In modern skincare, it appears in cleansers, toners, serums, and spot treatments at concentrations typically between 0.5 and 2 percent.
How they work
Unlike AHAs, BHAs are oil-soluble. This is the key distinction. Because salicylic acid can dissolve in oil, it can penetrate through the sebum inside a pore and reach the cells lining the pore wall from the inside. AHAs cannot do this. They work only on the skin surface.
Inside the pore, salicylic acid breaks down the dead cell buildup that causes blocked pores and comedones. It also has mild anti-inflammatory properties. This combination of exfoliation plus anti-inflammatory action is why salicylic acid is the most clinically useful over-the-counter ingredient for oily, congested, or acne-prone skin.
What BHAs are good for
- Oily or combination skin
- Blackheads and whiteheads (comedonal acne)
- Active breakouts and mild inflammatory acne (for moderate to severe acne, a prescription treatment is more appropriate)
- Enlarged pores
- Congested skin that feels rough to the touch
BHAs on Indian skin
Salicylic acid is generally well-tolerated on Indian skin at the concentrations available in over-the-counter products (0.5 to 2 percent). It is less likely than glycolic acid to trigger post-inflammatory hyperpigmentation in darker skin tones. In dermatology practice, salicylic acid peels at 20 to 30 percent are regularly used for acne and acne-related pigmentation on Indian skin with a good safety record when done by a trained clinician.
One caution for patients with very dry or sensitive skin: salicylic acid can be drying with daily use. Starting every other day and using a good moisturiser after application prevents the dryness that can paradoxically trigger more oil production.
PHAs: Polyhydroxy Acids
What they are
The most common PHAs in skincare products are gluconolactone and lactobionic acid. They are structurally similar to AHAs but have larger, more complex molecular structures.
How they work
PHAs exfoliate by the same basic mechanism as AHAs, breaking the bonds between dead skin cells and the surface below them. But their larger molecular size means they penetrate the skin much more slowly. This slow penetration is precisely what makes PHAs the gentlest of the three categories.
PHAs also have humectant properties, meaning they attract water molecules and help keep the skin hydrated as they exfoliate. Most AHAs do not do this to the same degree. This dual exfoliant-and-hydrator action makes PHAs particularly suitable for patients who need exfoliation but cannot tolerate the dryness or irritation that AHAs or BHAs sometimes cause.
What PHAs are good for
- Sensitive or reactive skin
- Skin with rosacea or redness
- Dry skin that needs exfoliation but not additional dryness
- Patients who have reacted badly to AHAs or BHAs in the past
- Beginners who want to introduce exfoliation gradually
- Patients using prescription retinoids who want a gentle co-exfoliant
Comparison Table
| AHA | BHA | PHA | |
|---|---|---|---|
| Examples | Glycolic acid, lactic acid, mandelic acid | Salicylic acid | Gluconolactone, lactobionic acid |
| Solubility | Water-soluble | Oil-soluble | Water-soluble |
| Where it works | Skin surface (stratum corneum) | Surface and inside the pore | Skin surface (slowly) |
| Primary benefit | Pigmentation, brightness, texture | Acne, oiliness, pore size | Gentle exfoliation with hydration |
| Irritation potential | Moderate to high (glycolic highest) | Low to moderate | Low |
| Best for skin type | Dry, pigmented, dull | Oily, acne-prone, congested | Sensitive, rosacea-prone, beginners |
| Safe OTC concentration | 5 to 15 percent | 0.5 to 2 percent | 5 to 15 percent (gluconolactone) |
| PIH risk on Indian skin | Moderate to high if misused | Low | Very low |
| Can combine with retinoids | With caution | With caution | Generally yes, with guidance |
Why Indian Skin Needs Extra Caution
The point about post-inflammatory hyperpigmentation is worth expanding because it is the mistake dermatologists see most often in patients who have experimented with chemical exfoliants at home before coming in for a consultation.
The Indian Association of Dermatologists, Venereologists and Leprologists (IADVL) recognises PIH as one of the most common and most undertreated skin concerns in Indian patients, particularly in the context of cosmetic procedures and active ingredients used at home.
Indian skin (Fitzpatrick type IV to VI) has more active melanocytes than lighter skin types. These cells are more easily triggered. Any inflammation, including the low-level, invisible inflammation that an acidic product can cause, can prompt them to produce melanin as a protective response. The result is a dark patch that can take months to fade.
The risk is higher with glycolic acid than with lactic or mandelic acid. It is higher at concentrations above 10 percent. It is higher when the product is used more than three times a week without adequate SPF the following morning. And it is higher when multiple actives are layered on top of each other.
If you have developed dark patches after using an exfoliant, a dermatologist can assess whether this is PIH, contact dermatitis, or a worsened underlying condition such as melasma. Each has a different treatment pathway.
Common Mistakes Dermatologists See
Using glycolic acid as a starting point: Patients read that glycolic acid is the most effective AHA and start there. For Indian skin, lactic or mandelic acid at a similar concentration is a more appropriate entry point because of the lower irritation risk.
Daily use from day one: Chemical exfoliants are not daily moisturisers. Starting daily use immediately increases the risk of over-exfoliation, which disrupts the skin barrier and paradoxically makes skin more sensitive, not less.
Skipping SPF the morning after: AHAs make skin more photosensitive for 24 to 48 hours after application. Using one without applying SPF 30 or above the following morning is counterproductive for anyone using it to address pigmentation.
Layering multiple acids: A BHA toner in the morning and an AHA serum at night does not produce twice the result. It produces twice the irritation. These ingredients are most effective when used on alternating days or on separate days rather than stacked.
Using AHAs around the eyes without checking concentration: The skin around the eye is thinner than the rest of the face. Any AHA above 5 percent can cause stinging, irritation, or milia around the eye area. PHAs are a safer option for patients who want exfoliation close to the eye.
Expecting quick results: Chemical exfoliants work on a skin cell turnover cycle of roughly 28 days. Most patients need 6 to 8 weeks of consistent use to see meaningful changes in texture or pigmentation. Stopping after two weeks because nothing has happened is one of the most common reasons they do not work in practice.
How to Introduce a Chemical Exfoliant Safely
The following approach applies to over-the-counter products at typical concentrations. Professional peels at a dermatology clinic use higher concentrations under controlled conditions and follow a different protocol.
- Start with one product, one ingredient. Not a multi-acid formula.
- Begin two to three times per week, in the evening. Not daily.
- Apply to clean, dry skin. Wait 10 to 15 minutes before applying moisturiser.
- Apply SPF 30 or above every morning without exception throughout the course of use.
- Do not combine with other active ingredients on the same evening until you know how your skin responds. Retinoids, benzoyl peroxide, and vitamin C serums should each be introduced on separate evenings.
- If you experience redness, stinging that lasts more than a few minutes, or a new dark patch within a week of starting, stop and consult a dermatologist before continuing.
The guideline for Indian skin in particular: start with lactic acid at 5 to 8 percent, or mandelic acid at 5 to 10 percent, or salicylic acid at 1 to 2 percent depending on whether your primary concern is surface pigmentation or oiliness. Give the product 6 weeks before evaluating. Only then consider adjusting concentration or frequency.
When to See a Dermatologist
If you have active inflammatory acne with pustules or cysts, a prescription treatment will be more effective and safer than a salicylic acid cleanser.
If you have melasma, over-the-counter AHAs alone will not resolve it. Melasma has a vascular component and often requires a combination approach that a dermatologist structures based on your specific pattern.
The Indian Journal of Dermatology, Venereology and Leprology has published multiple studies on combination therapy for melasma in Indian skin. A dermatologist-led plan combining prescription depigmenting agents with a clinic peel is significantly more effective than OTC exfoliants alone.
If your skin has reacted badly to an over-the-counter acid product and you now have a new dark patch or persistent redness, a dermatologist can assess whether it is PIH, contact dermatitis, or a worsened underlying condition.
If you want a more concentrated peel for acne scars, texture, or pigmentation, a clinic-administered chemical peel at 20 to 50 percent is in a different clinical category from anything you can safely apply at home.
At DermaVue, a skin consultation includes an assessment of your current product routine. If chemical exfoliants are part of what you are using or considering, the dermatologist will evaluate your skin type, your current concerns, and whether what you are using is appropriate, insufficient, or potentially counterproductive. Book a consultation at your nearest DermaVue branch.
Chemical Exfoliant Assessment at DermaVue
DermaVue offers skin consultations at all seven clinics across Kerala and Tamil Nadu. An assessment of your current skincare routine, including any exfoliants you are using, is part of a standard consultation.
All consultations are conducted by IADVL-registered MD DVL dermatologists. Clinic-grade chemical peels at concentrations appropriate for Indian skin are available at all branches for patients who need more than OTC exfoliants can offer.
| Branch | Address | Phone / WhatsApp |
|---|---|---|
| Thiruvananthapuram | TC 42, 3003-2, Poojappura Main Rd, Kesari Nagar, Chengalloor, TVM 695012 | +91 83308 60007 |
| Kollam | UMK Arcade, Vellayittambalam, Kavanad PO, Kollam 691003 | +91 80868 60465 |
| Thiruvalla | Iykara Peniel Tower, Opp. Indian Overseas Bank, Thukalassery, Thiruvalla 689101 | +91 80860 00608 |
| Kottayam | Zion Towers, Second Floor 101, SH 1, Thellakom, Kottayam 686631 | +91 81298 83331 |
| Kochi (Aluva) | Metro Pillar No. 57, Tamarind Rajadhani Building, Near Pulinchodu, NH-47, Aluva 683101 | +91 90720 07733 |
| Thrissur | Ardra Arcade, Opp. Akshaya Hotel, Punkunnam, Thrissur 680002 | +91 73567 42225 |
| Coimbatore | 460, Ponnaiyan St, Cross Cut Rd, Ram Nagar, Gandhipuram, Coimbatore 641009 | +91 80868 60018 |
Book a consultation by visiting your nearest branch, calling the branch number, or WhatsApp our Thiruvananthapuram team for the nearest clinic to you.
Related Reading
- Acne Treatment at DermaVue
- Melasma Treatment at DermaVue
- Chemical Peel at DermaVue
- Pigmentation Treatment at DermaVue
- All Procedures at DermaVue
Recommended Viewing
Still wondering which chemical exfoliant is right for your skin? Our team explains what a clinic-grade chemical peel does and what to expect during a session.
Chemical Peel for Indian Skin: What to Expect | DermaVue
Frequently Asked Questions
What is the difference between AHA, BHA, and PHA? AHAs (alpha-hydroxy acids like glycolic, lactic, and mandelic acid) are water-soluble and work on the skin surface to exfoliate dead cells and improve pigmentation and texture. BHAs (beta-hydroxy acids, primarily salicylic acid) are oil-soluble and can penetrate into the pore to clear congestion and reduce acne. PHAs (polyhydroxy acids like gluconolactone) are the gentlest category and exfoliate slowly while also hydrating the skin, making them suitable for sensitive skin types.
Which chemical exfoliant is best for Indian skin? There is no single best choice because it depends on the concern. For oily or acne-prone Indian skin, salicylic acid (a BHA) at 1 to 2 percent is the most appropriate starting point. For pigmentation, dark spots, or dull skin, lactic acid or mandelic acid (both AHAs) are preferable to glycolic acid because they cause less irritation on Indian skin tones. For sensitive skin, PHAs are the safest starting point. All of these choices should come with consistent SPF use the following morning.
Can I use glycolic acid on dark Indian skin? Yes, glycolic acid can be used on Indian skin, but it carries a higher risk of post-inflammatory hyperpigmentation than lactic acid or mandelic acid because it penetrates more quickly and can cause low-level irritation that triggers melanin production. If you are using glycolic acid on Indian skin for the first time, start at a low concentration (5 to 8 percent), use it no more than twice a week, and apply SPF 30 or above every morning without exception.
Can I use AHAs and BHAs together? Using them on the same day or at the same time increases irritation risk without significantly improving results. A more effective approach is to use a BHA on days when oiliness and congestion are the concern, and an AHA on separate days when texture and pigmentation are the focus. When in doubt, consult a dermatologist before layering actives.
How often should I use a chemical exfoliant? Most patients do best starting with two to three times per week, in the evening. Daily use from the start increases the risk of over-exfoliation and barrier disruption, which can cause redness, sensitivity, and flaking. After 4 to 6 weeks of consistent use without irritation, you can consider increasing frequency.
Should I use a chemical exfoliant if I am already on a retinoid prescription? This depends on what the retinoid is and the concentration. Retinoids and AHAs used on the same evening can cause significant irritation in many patients. PHAs are generally better tolerated alongside retinoids. If you are on a prescription retinoid such as tretinoin, adapalene, or isotretinoin, speak to your dermatologist before adding any chemical exfoliant to your routine.
Do chemical exfoliants remove dark spots? AHAs, particularly glycolic acid and lactic acid, can improve the appearance of post-inflammatory hyperpigmentation and mild sun-related dark spots over several weeks of consistent use. They are not a treatment for melasma, which has a deeper vascular and hormonal component. For melasma or deeper pigmentation, a dermatologist-supervised treatment plan is more appropriate.
What is the difference between a chemical peel at a clinic and an AHA product at home? The concentration is the primary difference. OTC AHA products use 5 to 15 percent concentrations. Clinic-grade chemical peels use 20 to 70 percent concentrations under controlled conditions with trained supervision. The mechanism is the same but the depth of effect is significantly different. OTC products address surface texture over weeks. Clinic peels address deeper scarring, pigmentation, and texture concerns more quickly and with a planned aftercare protocol.
Authored by Dr. Sarath Chandran, MD DVL, IADVL-registered dermatologist and Managing Director, DermaVue Clinics. Published July 2026. This article is for general information and does not substitute a clinical consultation. Individual results vary based on skin type, concern, and treatment adherence.
