Ultra Pure High-Potency 9.8% Glycolic Acid Serum
Ultra Pure High-Potency 9.8% Glycolic Acid Serum
Product Description
Product overview
A concentrated facial serum with 9.8% pure glycolic acid in an ultra-minimal 7-ingredient formula. This high-potency AHA exfoliant visibly smoothes skin texture, minimizes the appearance of pores, and boosts radiance without fragrance or colorants.
Ultra-Pure Formula
Only 7 carefully selected ingredients for maximum efficacy and minimal irritation risk.
Texture & feel
SENSORYUltra-Pure Formula
Only 7 carefully selected ingredients for maximum efficacy and minimal irritation risk.
Visible Texture Refinement
9.8% glycolic acid concentration visibly smoothes skin and minimizes pore appearance.
Hyaluronic Acid Infused
Contains sodium hyaluronate to maintain hydration while exfoliating for balanced results.
Clean Formula
Free from fragrance, colorants, parabens, and unnecessary fillers for sensitive-skin friendly use.
Safety & compatibility
SAFEAt 9.8%, this is just under the 10% threshold generally considered safe during pregnancy. ACOG approves OTC glycolic acid, but consult your healthcare provider. Safe for breastfeeding as minimal absorption occurs.
Contains no fatty acids, oils, esters, or ferments that feed malassezia yeast. Glycolic acid can actually help treat fungal acne by promoting exfoliation.
Rating 0/5. Minimal ingredient formula with no known pore-clogging ingredients. Excellent for acne-prone skin.
Glycolic acid increases photosensitivity. Must use SPF 30+ sunscreen daily when using this product. Apply only in PM routine.
Ingredient breakdown
INGREDIENTSGlycolic Acid 9.8%Proven
The gold standard AHA for chemical exfoliation. Glycolic acid has the smallest molecular size among AHAs, allowing deeper penetration into skin to dissolve bonds between dead skin cells.
- Research: Concentrations between 5-20% shown effective in clinical studies for texture improvement and collagen stimulation.
- Benefits: Exfoliates dead skin, improves texture, boosts radiance, increases cell turnover, fades hyperpigmentation.
- Source: Derived from sugar cane - a naturally occurring fruit acid.
Sodium Hyaluronate SupportingProven
The salt form of hyaluronic acid - a powerful humectant that can hold up to 1000x its weight in water. Helps counterbalance any drying effects from the glycolic acid.
- Function: Attracts and retains moisture in the skin for plumping and hydrating effects.
- Molecular Weight: Being the sodium salt form, it penetrates effectively into skin layers.
Glycerin SupportingProven
A classic humectant naturally found in skin. Studies show glycerin can be more effective than hyaluronic acid at hydrating skin in certain conditions.
- Benefits: Moisturizes, protects skin barrier, has antimicrobial properties.
- Source: Typically derived from vegetable oils in cosmetics.
7 ingredients
Aqua/Water, Glycolic Acid, Glycerin, Alcohol Denat., Sodium Hydroxide, Sodium Hyaluronate, Hydroxyethylcellulose
Where it fits in your routine
ROUTINEPM routine only. Apply after cleansing to clean, dry skin. Follow with hydrating serum and moisturizer. Can be layered with Kiehl's Hyaluronic Acid or Niacinamide serums.
How to use
HOW TO USECleanse Thoroughly
Start with clean, dry skin in the evening. Remove all makeup and impurities before application.
Apply 2-3 Drops
Dispense 2-3 drops onto fingertips and gently press into face and neck, avoiding eye area.
Allow Absorption
Wait 30-60 seconds for full absorption before layering additional products.
Follow with Moisturizer
Apply your favorite hydrating serum and moisturizer to seal in benefits and prevent dryness.
Sunscreen Next Morning
Always apply SPF 30+ the following day. AHAs increase sun sensitivity significantly.
Who is it for?
WHOPerfect for you if:
- You have dull, rough, or uneven skin texture
- You want to minimize the appearance of pores
- You prefer minimal, clean-ingredient formulas
- You have oily or combination skin
- You're experienced with chemical exfoliants
- You want to boost skin radiance and glow
- You have concerns about fungal acne
Consider alternatives if:
- You have very sensitive or reactive skin
- You're new to AHAs (start with lower %)
- You're pregnant and want to be extra cautious
- You use prescription retinoids daily
- You have active rosacea or eczema flares
- You can't commit to daily sunscreen use
Skin type compatibility
SKIN TYPESIdeal match. Lightweight, fast-absorbing formula controls excess oil while refining texture. No greasy residue.
Works well across different face zones. Can target oily T-zone while glycerin and HA support drier areas.
Perfect for maintaining healthy skin and boosting radiance. Great for prevention and glow enhancement.
Beneficial for texture, but follow with rich moisturizer. Contains alcohol denat. which may be slightly drying.
Fragrance-free is good, but 9.8% is potent. Start with 1-2x weekly. Consider lower % alternatives if irritation occurs.
Non-comedogenic, fungal acne safe. Helps unclog pores and improve post-acne texture. Zero comedogenic ingredients.
Results timeline
WEEK 4Refined Texture Feel
Skin immediately feels smoother to the touch. May experience slight tingling during application as the acid works.
83% noticed in clinical studyBoosted Skin Renewal
Cell turnover accelerates. Skin begins shedding dead cells more efficiently, revealing fresher skin underneath.
Visible renewal beginsSofter, Smoother Skin
Noticeable improvement in skin softness and texture. Rough patches diminish. Skin appears more radiant.
98% reported softer skinMinimized Pores & Glow
Visible reduction in pore appearance. Enhanced overall radiance and more even skin tone. Full benefits realized.
Visible pore reductionRatings by platform
410+ REVIEWSPros & cons
BALANCEDPraised
- Ultra-minimal 7-ingredient formula
- High 9.8% glycolic acid concentration
- Fragrance and colorant-free
- Fast-absorbing, lightweight texture
- Visible results within one week
- Fungal acne safe formula
- Layers well with other serums
- Clinically tested with proven results
Criticized
- Premium price point ($40/oz)
- Small 30ml bottle size
- Contains alcohol denat. (may dry skin)
- Can be too potent for sensitive skin
- Requires strict sunscreen use
- Not suitable for beginners to acids
- PM use only limits flexibility
Budget-friendly alternatives (dupes)
DUPESLower 7% concentration in a toner format (240ml). More ingredients including botanical extracts. Incredible value but not as potent or minimally formulated.
Similar 8% glycolic acid in a gel formula (3.3oz). Contains chamomile and green tea for soothing. More product for similar price, slightly lower concentration.
12% AHA/BHA blend with glycolic, lactic, tartaric, citric, and salicylic acids. More complex multi-acid formula. Premium price, different approach to exfoliation.
7% glycolic acid K-beauty favorite (100ml). Contains apple water and niacinamide. Different formula philosophy but great value for AHA beginners.
Comparison with competitors
SIDE-BY-SIDEStorage & shelf life
12 MONTHS12 months after opening
Store in a cool, dry place away from direct sunlight. Keep tightly closed.
Glass dropper bottle with protective box. Recyclable packaging.
Yes - 30ml is under the 100ml TSA liquid limit for carry-on bags.
Frequently asked questions
FAQAt 9.8% glycolic acid, this product is just under the 10% threshold generally considered safe during pregnancy by the American College of Obstetricians and Gynecologists. However, during pregnancy, it's advisable to consult with your healthcare provider before use. For breastfeeding, glycolic acid is considered safe as minimal amounts are absorbed systemically and unlikely to appear in breast milk. Avoid applying to areas that may come in contact with your baby.
Yes! This serum is fungal acne safe. The 7-ingredient formula contains no fatty acids, oils, esters, ferments, or polysorbates that feed malassezia yeast. Glycolic acid can actually help treat fungal acne by promoting exfoliation and keeping pores clear. This makes it an excellent choice for those prone to pityrosporum folliculitis.
Use caution when combining actives. Avoid using this serum in the same routine as other direct acids (like salicylic acid or lactic acid) or strong retinoids to prevent over-exfoliation and irritation. You can alternate days - for example, glycolic acid on Monday/Wednesday/Friday and retinol on Tuesday/Thursday/Saturday. Vitamin C can be used in your AM routine while this serum is PM only. Kiehl's recommends layering with their Hyaluronic Acid or Niacinamide serums for enhanced benefits.
This serum is best suited for oily, combination, and normal skin types. The lightweight, fast-absorbing formula works excellently for those wanting to control oil while refining texture. It's also excellent for acne-prone skin due to its non-comedogenic formula. Those with dry skin can use it but should follow with a rich moisturizer. Sensitive skin types should start slowly (1-2x weekly) and consider lower concentration alternatives if irritation occurs.
Based on clinical studies: 83% feel refined texture instantly after application. Within 3 days, skin renewal is boosted. By week 1, 98% of users report softer skin with visibly smoother texture. By week 4, you'll see reduced pore appearance and enhanced radiance. For best results, use consistently 2-3 times weekly, building up to daily use as tolerated.
Apply in your PM routine only: 1) Cleanse thoroughly, 2) Apply toner (optional), 3) Apply 2-3 drops of this serum to clean, dry skin, 4) Wait 30-60 seconds, 5) Follow with treatment serums if desired, 6) Apply moisturizer. Always use SPF 30+ the following morning as glycolic acid increases sun sensitivity significantly.
No - this serum has a comedogenic rating of 0/5. The ultra-minimal 7-ingredient formula contains no known pore-clogging ingredients. In fact, glycolic acid helps unclog pores by dissolving the bonds between dead skin cells. It's an excellent choice for acne-prone skin and won't contribute to breakouts or blackheads.
The Period After Opening (PAO) is 12 months. Store in a cool, dry place away from direct sunlight and keep the bottle tightly closed when not in use. The 30ml bottle typically lasts 2-3 months with regular use (2-3 drops daily), so you should use it well within the 12-month timeframe. Discard if the texture, color, or smell changes significantly.
Verdict: Kiehl's Ultra Pure High-Potency 9.8% Glycolic Acid Serum delivers on its promise of a minimal, high-efficacy formula. The 7-ingredient approach ensures maximum active delivery without unnecessary fillers, making it ideal for those who want straightforward, effective exfoliation. At 9.8% glycolic acid, it's potent enough to deliver visible results within a week while being just under the pregnancy-safe threshold. The fragrance-free, fungal acne-safe formula is a standout feature. The main drawback is the premium price point at $40 for just 1oz - significantly more expensive per ounce than competitors like Paula's Choice or The Ordinary. Best for: experienced acid users with oily/combination skin who value clean, minimal formulas and don't mind paying premium for the Kiehl's heritage and quality.
Product Overview
Quick product notes are a great way to check if a product is free from commonly avoided ingredients by skincare enthusiasts. These preferences come about for different reasons depending on the ingredient such as personal experiences, sensitivities, health preferences & etc.
Just because a product is not free from a common preference does not mean it's a bad product! You can make a personal decision whether or not you want to use a product that contains these ingredients or not - click the labels of the preference to read more about them.
Quick Product Notes
Ever used a product that promised a certain effect but provided no results? It might not have contained any notable ingredients that could have been responsible for that promised effect. It doesn't matter what the marketing or packaging «promises» it can do, if it doesn't contain anything that can help - then the likelihood of it helping is low.
We help you identify key notable ingredients that have been shown to help with effects such as acne-fighting, brightening, UV-protection, wound healing & anti-aging to help you achieve your skincare goals smarter. Please note that different notable ingredients have varying levels of research behind them, some are extremely well proven yet some have mixed research in their efficacy.
Just because a product doesn't contain any notable ingredients doesn't mean it's bad. And a product with notable ingredients (or even many) doesn't necessarily guarantee the efficacy of the product performing these effects either. There are other factors such as ingredient quality, concentration and formulation that will ultimately determine this.
Be smart and use this as just a starting point for you to make more informed and smarter choices and compare it with reviews to see if the product is right for you
Notable Effects & Ingredients
Why are some products great for some people and horrible for others? Well everyone has different skin types and different reactions to the same ingredients.
We've identified a range of ingredients that are commonly regarded as potentially good or bad for those with Dry, Oily/Acne-Prone or Sensitive skin.
A product that contains good or bad ingredients for your skin type doesn't always flat out make the entire product good or bad for your skin. There are other factors such as ingredient quality, concentration and formulation that will ultimately determine your skins reaction.
One of the best ways to use this section is to troubleshoot products you've had bad experiences with in the past. Check if it contains any of the marked ingredients to point out suspect ingredients to avoid in the future!
Ingredients Related to Skin Types
Ingredient Safety Breakdown refers to the percentage % of ingredients in different risk categories as classified by EWG (Environment Working Group) if they are available. There are almost endless cosmetic ingredients and they are one of the few organisations globally that have assigned ratings to a lot of the more commonly used ingredients which is why we reference them.
EWG is seen by many to be more on the alarmist side in their assignment of health ratings resulting in rating ingredients as riskier than they actually are. We recommend using this a reference point rather than a strict guide of ingredient safety and to always do further research if into ingredients that you may find suspect.
Ingredient Safety Breakdown
Product ingredient list
| EWG | CIR | Ingredient Name & Cosmetic Functions | Notes |
|---|---|---|---|
| 1 |
Water
Solvent, Skin Conditioning
|
|
|
| 4 |
Glycolic Acid
Ph Adjuster, Buffering Agent, Exfoliant, Exfoliating, Buffering
|
Promotes Wound Healing
Dark Spots
Texture
Pores
|
|
| 2 |
Glycerin
Solvent, Perfuming, Fragrance, Humectant, Viscosity Decreasing Agent, Hair Conditioning, Skin Protecting, Denaturant, Skin Conditioning
|
Promotes Wound Healing
Hydrating
|
|
| 0 |
Alcohol Denat.
|
|
|
| 3 |
Sodium Hydroxide
Ph Adjuster, Buffering Agent, Denaturant, Buffering
|
|







