The Science Behind Next Generation Exfoliants: 

AHAs, BHAs, and PHAs

Exfoliation has evolved far beyond the traditional concept of scrubbing away dead skin cells. In 2025, consumers are embracing intelligent exfoliation — a science-driven approach that optimizes skin renewal while maintaining barrier integrity. This shift marks a departure from aggressive acids and physical abrasives toward formulations that are precise, biocompatible, and tailored to individual skin needs.

At the core of this transformation lie three molecular groups that have defined the new era of dermatological exfoliation:  Alpha Hydroxy Acids (AHAs), Beta Hydroxy Acids (BHAs), and Polyhydroxy Acids (PHAs).

Each class of molecule provides distinct biochemical actions, enabling targeted treatment for different skin conditions. Yet as innovation surges, so do controversies surrounding ingredient concentration limits, over-formulation, and the growing tension between clinical efficacy and influencer-driven marketing.

1. Alpha Hydroxy Acids (AHAs): The Cellular Renewers

Representative molecules: Glycolic acid, lactic acid, mandelic acid

AHAs are water-soluble acids derived primarily from fruit, milk, or sugar. They work by disrupting the ionic bonds between corneocytes—the dead cells on the skin’s surface—promoting desquamation and cellular renewal.

Key Benefits

• Increases epidermal turnover and improves texture uniformity

• Stimulates collagen synthesis, enhancing elasticity and firmness

• Reduces visible photodamage and pigmentation irregularities

Industry Debate: Concentration vs. Tolerance
The growing trend of “peel-at-home kits” has reignited discussion over safety thresholds. Some dermatologists warn that consumer formulations often exceed the 10% AHA limit recommended for unsupervised use, potentially leading to micro-inflammation and barrier erosion. Meanwhile, pro-formulators argue that low-pH glycolic systems with optimized buffering can outperform traditional 30% peels with fewer side effects.

Clinical Relevance in 2025
The professional consensus is shifting toward controlled exfoliation: combining AHAs with peptides, postbiotics, or amino acids to strengthen the barrier while resurfacing the skin. “Resurface-and-repair” systems now dominate professional and luxury skincare, seen in clinical brands like Pietro Simone and Dr. Dennis Gross — where efficacy no longer comes at the expense of tolerance.

2. Beta Hydroxy Acids (BHAs): The Deep-Pore Clarifiers

Representative molecule: Salicylic acid

Unlike AHAs, BHAs are lipid-soluble, enabling them to penetrate deep into pores and exfoliate within the follicle lining. This makes them particularly effective for oily or acne-prone skin.

Key Benefits

• Dissolves oil, debris, and keratin plugs that cause congestion

• Provides antimicrobial and anti-inflammatory properties

• Reduces blackheads and refines pore structure

Industry Debate: The “Barrier-Burnout” Phenomenon
As salicylic acid resurges in popularity—particularly in toners and spot treatments—dermatologists are seeing a rise in what’s being termed “barrier burnout.” Overuse of exfoliating acids, even in low concentrations, has been linked to chronic dryness, redness, and micro-cracking of the skin barrier. This raises questions about the sustainability of daily acid routines promoted across social media.

Current Trends
Leading formulators are countering this issue with adaptive exfoliation — pairing BHAs with niacinamide, panthenol, or beta-glucan to balance the skin’s microbiome while preventing dehydration. The modern philosophy of “pore health” focuses on restoration, not aggression — a stark contrast to the once-popular “purge” trend that dominated the early 2020s.

3. Polyhydroxy Acids (PHAs): The Barrier-Safe Exfoliants

Representative molecule: Gluconolactone

PHAs represent the newest evolution of exfoliation science. With larger molecular structures and humectant properties, they deliver gentle resurfacing suitable for sensitive or post-procedure skin.

Key Benefits

• Provides mild exfoliation and hydration simultaneously

• Strengthens barrier function and reduces transepidermal water loss

• Offers antioxidant protection and inhibits collagen glycation

Industry Debate: Are PHAs Truly “Irritation-Free”?
Although marketed as universally gentle, new studies indicate that PHAs in poorly stabilized formulations may oxidize rapidly, potentially leading to reactive byproducts that irritate compromised skin. This challenges the perception that PHAs are entirely risk-free. However, when properly stabilized, they remain among the most biocompatible acids available — particularly valuable in “barrier recovery” or “post-treatment” product lines.

Emerging Role in Skincare
In 2025, PHAs are at the heart of the “skin barrier defense” category. Their compatibility with retinoids and peptides allows for multi-active layering — supporting the shift toward results-driven yet soothing formulations. Their clinical adoption continues to rise as luxury spas move away from aggressive peels toward holistic rejuvenation protocols.

4. The New Paradigm: Intelligent Exfoliation and Skin Data

The defining movement in modern exfoliation is personalization through data. Artificial intelligence and digital diagnostics are now capable of analyzing parameters such as pH balance, barrier condition, and lipid composition to determine optimal acid selection and usage frequency.

Adverto Beauty’s forthcoming AI Skin Analyzer integrates this principle into a real-time evaluation system, allowing users to receive personalized exfoliation protocols based on their unique skin physiology.

Industry Debate: Technology vs. Human Expertise
While AI-driven skincare promises precision, it has also sparked debate within the professional esthetics community. Some practitioners express concern that algorithmic recommendations may oversimplify complex dermal interactions, leading to “data-driven overconfidence.” Others view AI as an essential advancement that democratizes dermatological insight, enabling broader access to clinically validated routines.

This convergence of chemistry, biology, and digital intelligence marks the rise of Skin Intelligence Care (SIC) — a methodology that prioritizes informed, sustainable, and adaptive exfoliation rather than routine overuse.

The modern skincare landscape acknowledges that efficacy must coexist with skin health.

• AHAs refine and rejuvenate through controlled resurfacing.

• BHAs clarify and rebalance the pores.

• PHAs exfoliate while reinforcing the skin barrier.

Together, they form the triad of next-generation exfoliation — rooted in evidence, guided by personalization, and designed for long-term resilience rather than short-term results.

Yet the controversies surrounding acid concentration, barrier health, and algorithmic skincare underscore a critical truth: the future of exfoliation does not lie in intensity, but in intelligence — where data, science, and ethical formulation intersect to support truly sustainable skin health.