Ultra Pure High-Potency 9.8% Glycolic Acid Serum

Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum is a deliberately short formula — seven ingredients in total. Kiehl's keeps it minimal so the glycolic acid absorbs cleanly and the smoothing effect is not competing with anything else in the bottle.

Skin types	Normal, dry, combination and oily
Targets	Pores and uneven texture
Strength	Glycolic acid at 9.8%
Ingredient count	Seven
Free from	Fragrance · colorants · recyclable packaging

What it actually does

• Smooths the surface. Glycolic acid is a naturally occurring fruit acid, and Kiehl's cites it as known for visibly smoothing skin.
• Refines texture and pores. Those are the two concerns the serum is positioned against.
• Adds glow. Boosting radiance is listed alongside the texture work.
• Minimal by design. Seven ingredients, nothing added for scent or colour — the brand's stated aim is absorption and a clean smoothing effect.
• What the consumer study reported. In a four-week study, 98% agreed their skin felt softer after just one week. Brand-cited figure — individual results vary.

How to use

1. Night-time only. Put two or three drops onto skin that is clean and dry.

Kiehl's own layering suggestions: treat the face by zone, putting its Ultra Pure High-Potency 5.0% Niacinamide Serum where you get oily or break out, then moisturising where it is needed. The brand also suggests pairing this serum with its Ultra Pure Hyaluronic Acid 1.5% Serum for moisture. Each of those is sold separately. A reminder worth adding: acids increase sun sensitivity, so wear SPF during the day.

Is it right for you?

Questions

Why only seven ingredients?

Kiehl's keeps the formula minimal so it absorbs well and the smoothing effect comes through. There is no fragrance and no colorant in it at all.

Can I use it in the morning?

The instruction is for evening use. Glycolic acid makes skin more sun-sensitive, so a night slot plus daytime SPF is the sensible pairing.

How much do I apply?

Two to three drops across clean, dry skin. More is not better with a concentrated acid.

Can I layer it with other Kiehl's serums?

The brand suggests combining it with its hyaluronic acid serum for hydration, and treating oily or breakout-prone zones with its niacinamide serum. Both are separate purchases.

Delivery, payment and returns?

Delivery takes 3 to 21 working days, depending on availability. Payment is by credit card, debit card, Instapay or mobile wallet — no cash on delivery. Returns are for defective, damaged or expired items only, reported within 1 day of delivery, refunded to the original payment method within 15–30 days.