How to Best Use Glycolic Acid in Your Skincare Routine —Even If You Have Oily Skin

Hand holding a vial of chemical with glycolic acid molecule structure

The Science of Acids and Bases in Skincare

Skincare is chemistry in action. Our skin naturally maintains a slightly acidic environment (pH 4.5–5.5) that protects against harmful microbes and supports the skin barrier. Acids in skincare, like glycolic acid, work by gently loosening dead skin cells and promoting cell turnover. Bases, on the other hand, adjust pH levels to make products safe and effective. Understanding this balance helps you use chemical exfoliants wisely and safely.

What Is Glycolic Acid and How It Works

Glycolic acid is an alpha-hydroxy acid (AHA) derived from sugar cane. Its small molecular size allows it to penetrate the skin efficiently. Glycolic acid exfoliates by breaking down the “glue” between dead skin cells, promoting smoother, brighter skin. Regular use can improve skin texture, reduce dullness, and enhance absorption of other active ingredients.

Which Acid Should You Use: AHA vs. BHA?


You may have heard the common advice: “Use AHAs if you have dry skin, and BHAs if you have oily skin.” While there’s some truth to this, it’s not a hard rule.

  • AHAs (like glycolic acid): Water-soluble and work on the skin’s surface, making them great for exfoliating dry, dull, or sun-damaged skin. They help smooth texture, brighten, and improve moisture absorption.

  • BHAs (like salicylic acid): Oil-soluble and can penetrate into pores, making them useful for acne-prone or oily skin, helping to clear clogged pores and reduce blackheads.

However, skin is complex, and many people have combination or sensitive skin. Sometimes a dry-skinned person may benefit from a low-concentration BHA to prevent occasional breakouts, and an oily-skinned person may benefit from an AHA to improve texture and brightness. The key is observing how your skin reacts and adjusting frequency, concentration, and combination of acids accordingly.

(I personally have very oily skin, but have benefited from using AHA! My only regret is getting too caught up in the “rules” and not trying glycolic acid sooner. It did take some trial and error to find the right concentration product, but it was well worth it.)

Safe Usage Guidelines for Glycolic Acid

  • Start Low, Go Slow: Begin with 5–10% concentrations if you’re new to AHAs.

  • Frequency: ~2 times per week is usually enough for beginners; more frequent use is possible as tolerance builds.

  • Sun Protection: Glycolic acid increases sun sensitivity. Always apply a broad-spectrum sunscreen during the day.

  • Layering: Avoid using strong exfoliants (like retinol or high-dose vitamin C) on the same day unless your skin is very resilient.

  • Patch Test: Apply to a small area first to check for irritation.

Which Skin Types Benefit Most

  • Oily or Acne-Prone Skin: Helps clear pores and reduce congestion.

  • Dull or Uneven Skin Tone: Promotes brighter, more uniform skin.

  • Aging Skin: Supports cell turnover and can smooth fine lines.

Caution: Extremely sensitive skin may react strongly. Begin with very low concentrations and monitor your skin’s response.

Professional-Grade vs. At-Home Glycolic Acid

Professional treatments typically contain higher concentrations (20–70%) and are administered by dermatologists or licensed aestheticians. These treatments offer more dramatic exfoliation and results but require careful handling. At-home products are generally 5–15% for safe weekly or daily use. 

An Unexpected Benefit: Glycolic Acid and Fungal-Related Flakiness

While glycolic acid is mainly known for exfoliation, it can also impact the skin environment in ways that affect microbes like Malassezia, the fungus behind dandruff. Malassezia can also affect the face, —for example, on the cheeks and chin—creating flaky patches often mistaken for dry skin. Unlike true dryness, these patches may not improve with heavy moisturizers and can sometimes worsen with occlusive creams, because the fungus thrives in damp conditions or areas of localized immune compromise (aka dermatitis, or seborrheic dermatitis).

By gently exfoliating dead skin cells, glycolic acid helps remove the layer of debris where the fungus resides. While glycolic acid is not a medical antifungal, this action can make skin appear smoother and less flaky—an interesting scientific benefit beyond cosmetic improvement.

(If you’ve been applying moisturizers daily for months and the “dry patch” never goes away, trying a chemical peel with an AHA—here, glycolic acid—can be eye-opening. You might be surprised at how much it improves in just a matter of a week.)

Takeaways

  • Introduce glycolic acid gradually and respect its potency.

  • Adjust concentration based on your skin type and tolerance.

  • Always protect your skin from the sun after use.

  • Consider professional-grade treatments for stronger exfoliation.

  • Glycolic acid’s ability to exfoliate and modify the surface environment may also reduce conditions favorable for fungal-related flakiness.

Conclusion
Glycolic acid is a versatile, science-backed skincare ingredient. From improving texture and brightness to potentially reducing fungal-related flakes, it works best when used safely and thoughtfully. By understanding the chemistry behind acids and bases, you can harness the power of glycolic acid to keep your skin smooth, healthy, and radiant.

 

Keywords: glycolic acid, AHA, exfoliation, chemical peel, flaky skin, Malassezia, safe skincare, professional skincare, at-home skincare

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