AHA vs BHA: What Each Acid Actually Does and Which Indian Skin Types Need More

AHA stands for alpha hydroxy acid. BHA stands for beta hydroxy acid. Both are chemical exfoliants, but they work on different layers of skin and target different problems. AHA is water-soluble. It works on the surface, dissolving the bonds that hold dead skin cells together so they shed. BHA is oil-soluble. It goes past the surface and into the pore itself, cutting through sebum to clear blockages from the inside.

The most common AHA is glycolic acid, derived from sugarcane, followed by lactic acid from milk. The only BHA in widespread skincare use is salicylic acid. These are not interchangeable. Applying a BHA to dry, flaky skin will not do what a glycolic toner would. Applying an AHA to a blackhead-dense nose will not reach where salicylic acid can.

Indian skin spans a wide range of Fitzpatrick types, mostly III through VI, and that matters for how acids behave. Darker skin tones produce more melanin as a stress response. Any inflammation, a popped pimple, a harsh scrub, even a sunburn, can trigger post-inflammatory hyperpigmentation, the dark marks that linger for months after the original problem has cleared. AHAs, particularly glycolic and lactic acid, have documented evidence for reducing this kind of pigmentation. A 2013 study published in the Journal of Cosmetic Dermatology found that glycolic acid peels significantly reduced melanin index in patients with melasma, a condition that disproportionately affects South Asian women.

Indian skin also contends with humidity for most of the year. In coastal cities like Mumbai and Chennai, and during monsoon months across the country, sebaceous glands work overtime. Pores enlarge, comedones form, and surface congestion becomes a chronic condition rather than a seasonal one. That is BHA's territory.

Pigmentation is the single most common skin concern cited by Indian dermatologists. Sun exposure is high and year-round. Hormonal changes from conditions like PCOS, which affects roughly one in five Indian women according to studies published in the Indian Journal of Endocrinology and Metabolism, drive melasma and uneven tone. AHAs accelerate cell turnover, bringing fresher, more evenly pigmented skin to the surface faster than it would arrive on its own.

Lactic acid is gentler than glycolic and better suited to skin that is reactive or new to acids. It also has mild humectant properties, meaning it draws moisture into the skin while it exfoliates. For Indian skin types prone to sensitivity or barrier disruption from years of harsh soap use, lactic acid at five to ten percent is often the more practical starting point than glycolic.

Salicylic acid at one to two percent is the workhorse for oily, acne-prone skin. Its oil-solubility means it can travel down the sebaceous filament and dissolve the plug of oxidised sebum that becomes a blackhead. It also has anti-inflammatory properties, which makes it useful not just for clearing existing breakouts but for calming the redness around them.

For Indian skin types with enlarged pores, a salicylic acid cleanser or toner used three to four times a week will do more than any clay mask or pore strip. The key is consistency, not concentration. Two percent salicylic acid used regularly outperforms five percent used once a fortnight.

One caution: BHA can be drying. If your skin feels tight or flaky after use, reduce frequency before reducing the product. Dryness triggers more sebum production, which defeats the purpose.

The practical split is this: if your primary complaint is dark marks, uneven tone, dullness, or rough texture, you need an AHA. If your primary complaint is blackheads, whiteheads, clogged pores, or persistent oiliness, you need a BHA. Most Indian skin types, dealing with both sun damage and humidity-driven congestion, need both, just not at the same time or in the same step.

A workable approach: use a BHA product in the morning on oily zones, and an AHA product at night when cell turnover is higher and the skin is not about to face UV exposure. AHAs increase photosensitivity, so sunscreen the following morning is not optional. This is not a precaution, skipping SPF after an AHA application actively worsens the pigmentation you were trying to fix.

Neither acid replaces moisturiser. Neither replaces SPF. They are exfoliants, not treatments that work alone. The melanin your skin over-produces in response to stress does not disappear because you applied an acid once. It responds to consistent, low-irritation exfoliation over weeks.

The deeper pattern is this: Indian skin is often sold a single-product solution to what is actually a two-part problem. AHA handles what sits on the surface. BHA handles what sits inside the pore. The skin that deals with both pigmentation and congestion, which describes most Indian skin types through most of the year, is not choosing between two acids. It is sequencing them.