Alpha Hydroxy Acids · Water-soluble

AHA Exfoliants

Surface-level chemical exfoliation that improves skin texture and evens out tone

Ingredients

Mechanism of Action

How It Works

Alpha hydroxy acids are water-soluble acids that work at the skin's surface by weakening the bonds holding dead corneocytes together. This allows the outermost layer of dead skin cells to shed more evenly, revealing fresher skin underneath. At higher concentrations, AHAs also stimulate collagen production in the dermis. Molecular size affects how each AHA behaves: glycolic acid is the smallest and penetrates deepest, lactic acid is larger and gentler with a useful humectant effect, and mandelic acid is the largest, making it the best-tolerated option for sensitive skin.

Best For

Dull or uneven skin tone
Fine lines and mild textural concerns
Dry or normal skin types
Hyperpigmentation and sun damage

Watch Out For

AHAs increase photosensitivity, so daily SPF is non-negotiable
Avoid combining with high-concentration retinoids or vitamin C in the same routine step
Start at lower concentrations (5 to 8%) and increase gradually
Not suitable for compromised or actively inflamed skin

What to Look For

Key Ingredients

Tap an ingredient to learn more

Glycolic Acid

The smallest AHA, offering the deepest penetration and the strongest resurfacing and collagen-stimulating effect

Lactic Acid

A gentle AHA with a built-in humectant effect, hydrating the skin as it exfoliates

Mandelic Acid

A large-molecule AHA suited to sensitive skin and darker skin tones

Tartaric Acid

A mild AHA often used in combination formulas to stabilise pH

Citric Acid

An antioxidant AHA that brightens skin and helps regulate formula pH

How to Use

Routine & Layering

Best used PM

Use AHAs in the evening on clean, dry skin. Apply after cleansing and before serums or moisturisers. Wait 10 to 15 minutes after application before layering other actives to allow the formula to work at its intended pH. Follow with a hydrating serum and moisturiser to offset any dryness.

AM Routine

Do not apply AHAs in the morning. Apply a broad-spectrum SPF30 or higher every morning without fail, as AHA use increases photosensitivity for at least 24 hours after application.

PM Routine

Begin with 2 to 3 applications per week and increase to every other night once the skin has acclimatised. Avoid combining with retinoids on the same night until the skin is fully adjusted to both.

Layering Order

1 Cleanser
2 AHA toner or serum
3 Wait 10 to 15 minutes
4 Hydrating serum
5 Moisturiser

Compatibility

Pairings & Interactions

Pairs Well With

Hydrating & Barrier Support

A hydrating serum or moisturiser applied after AHAs offsets dryness and supports barrier recovery

Brightening & Depigmentation

AHAs accelerate cell turnover, which amplifies the effect of brightening actives on pigmented skin

Antioxidants

Antioxidant serums applied the following morning help counteract the increased UV sensitivity AHAs cause

Avoid Combining With

Retinoids

Combining AHAs and retinoids on the same evening increases the risk of irritation and barrier disruption; alternate nights instead

BHA Exfoliants

Using AHAs and BHAs together in the same step can be unnecessarily aggressive; choose one per session unless the formula is specifically designed to combine them

PHA Exfoliants

There is no benefit to stacking AHAs with PHAs; choose one exfoliant type per routine step

Got Questions?

Frequently Asked Questions

How often should I use an AHA exfoliant?

Start with 2 to 3 times per week and assess how your skin responds. Once comfortable, some people tolerate daily use at lower concentrations. If you experience persistent redness, sensitivity, or flaking, reduce frequency and give the barrier time to recover.

What percentage of glycolic acid is safe to use at home?

Over-the-counter formulas typically range from 5% to 15%. Beginners should start at 5 to 8%. Concentrations above 10% are effective for resurfacing but increase irritation risk, especially on dry or sensitive skin. Anything above 20% is considered a professional-grade peel.

Can I use an AHA if I have sensitive skin?

Mandelic acid and lactic acid are the most suitable AHAs for sensitive skin due to their larger molecular size and slower penetration. Start at a low concentration and use no more than twice a week. If your skin barrier is already compromised, wait until it has recovered before introducing any exfoliant.

Why do AHAs increase sun sensitivity?

By removing the outermost layers of dead skin cells, AHAs expose newer, less UV-hardened skin to sunlight. This makes the skin more vulnerable to UV damage, sunburn, and pigmentation. Daily SPF30 or higher is essential while using AHAs and for at least a week after stopping.

Is it true that AHAs can help with anti-ageing?

Yes. At concentrations above 10%, AHAs stimulate fibroblast activity and collagen synthesis in the dermis. Consistent long-term use has been shown to improve fine lines, skin firmness, and surface texture. Glycolic acid has the strongest evidence base for this effect among AHAs.

Curated List