Which Exfoliating Acid Is Right for Your Skin?

If you've ever stood in front of a skincare shelf wondering whether you need glycolic, lactic, salicylic, mandelic or azelaic acid, you're not alone.

The truth is that not all exfoliating acids are created equal. While they're often grouped together, each acid has a different molecular structure, penetrates the skin differently, and targets specific concerns. Choosing the right one isn't about finding the "strongest" acid, it's about finding the one that's appropriate for your skin.

Here's what you need to know.

If your skin looks dull or feels rough: Glycolic Acid

Glycolic acid is often considered the gold standard for improving skin texture and brightness.

As the smallest alpha hydroxy acid (AHA), it has thelowest molecular weight, allowing it to penetrate more deeply into the skin than other AHAs. This deeper penetration produces more significant exfoliation, helping to remove accumulated dead skin cells and stimulate cellular turnover.

If your primary concerns are:

• Dullness
• Uneven skin tone
• Rough texture
• Early signs of ageing

Glycolic acid is an excellent place to start - provided your skin can tolerate it.

If your skin is dry or sensitive: Lactic Acid

Many people assume they can't use exfoliating acids because they have sensitive skin. Often, that's simply because they're using the wrong acid.

Lactic acid gently exfoliates the skin's surface while also acting as a humectant, drawing water into the skin. This dual action makes it one of the most hydrating exfoliating acids available.

It's ideal if you have:

• Dry skin
• Dehydrated skin
• Mild sensitivity
• A compromised skin barrier

For many people, lactic acid offers the benefits of exfoliation without the dryness commonly associated with strongeracids.

If you have pigmentation, rosacea or reactive skin: Mandelic Acid

Mandelic acid has the largest molecular weight of the AHAs, meaning it's absorbed more slowly and remains closer to the skin's surface.

The result? Effective exfoliation with a significantly lower risk of irritation.

It's particularly beneficial for:

• Hyperpigmentation
• Rosacea-prone skin
• Reactive or sensitive skin
• Darker skin tones where minimising post-inflammatory pigmentation is especially important

When your skin barrier needs extra care, mandelic acid is often the most appropriate choice.

If you're dealing with congestion, blackheads or acne: Salicylic Acid

Unlike AHAs, salicylic acid is a beta hydroxy acid (BHA).

Its key advantage is that it's oil-soluble, allowing it to travel through sebum and penetrate directly into the pore. Once inside, it helps dissolve the mixture of oil, dead skin cells and debris that contributes to congestion.

No other exfoliating acid works in quite the same way.

Salicylic acid is best suited for:

• Blackheads
• Congested pores
• Oily skin
  

If your breakouts begin beneath the skin's surface, salicylic acid is usually the most effective option.

If you have active breakouts and the marks they leave behind: Azelaic Acid

Although technically not an exfoliating acid in the same category as AHAs or BHAs, azelaic acid deserves a place in the conversation because of its impressive versatility.

It is:

• Antibacterial
• Anti-inflammatory
• Melanin-inhibiting

This means it not only helps reduce active acne lesions but also addresses the post-inflammatory pigmentation that often follows breakouts.

It's also one of the few active ingredients considered safe for use during pregnancy, making it an excellent option for many patients who need effective acne treatment during this time.

If you're new to acids or have highly sensitised skin: PHAs

Polyhydroxy acids (PHAs) are the gentlest members of the exfoliating acid family.

Because of their larger molecular structure, they work almost exclusively on the skin's surface, providing gentle exfoliation with minimal irritation.

PHAs also have inherent humectant and antioxidant properties, helping support the skin barrier while improving texture.

They're ideal for:

• First-time acid users
• Highly sensitive skin
• Barrier-compromised skin
• Anyone wanting gentle maintenance exfoliation

For manypeople, PHAs are the safest and most evidence-based starting point before progressing to stronger acids if needed.

The best exfoliating acid isn't the strongest one, it's the one that's matched to your skin's needs.

Your overall guide:

Dullness and texture? Glycolic acid.
Dry or sensitive skin? Lactic acid.
Pigmentation or rosacea? Mandelic acid.
Congestion and blackheads? Salicylic acid.
Acne and post-inflammatory pigmentation? Azelaic acid.
New to exfoliation or highly sensitive? PHAs.

When used appropriately, exfoliating acids can dramatically improve skin clarity, texture and overall skin health. The key is understanding that each acid has a different mechanism of action - and choosing accordingly rather than following trends.