Chemical peels have long been a cornerstone of cosmetic dermatology. Yet their biological impact extends far beyond simple superficial exfoliation. Current research is shedding light on a less familiar but fascinating mechanism: the activation of the Skin Stress Response System (SSRS), in particular through the induction of Proopiomelanocortin (POMC). Understanding this pathway sheds new light on how PRX PLUS, a topical skin enhancer based on ammonium trichloroacetate (ATCA) and homocysteic acid, achieves regenerating and harmonizing skin effects—without causing visible peeling or inflammation.

From Inflammation to Adaptation: The Skin’s Stress System
The skin has an independent neuroendocrine-like system that reflects the central stress axis. The cutaneous stress response system includes local production of:

Corticotropin-releasing hormone (CRH)
POMC-derived peptides, such as α-MSH, ACTH, and β-endorphin
They are not merely hormone vestigials; they regulate inflammation, pigmentation, and tissue homeostasis at the cellular level.

Kimura et al. in 2012 showed that trichloroacetic acid (TCA) chemical peeling activates the SSRS by stimulating POMC expression in keratinocytes independent of CRH stimulation. This implies that skin injury per se—when properly dosed—can initiate a regenerative, anti-inflammatory hormonal cascade, restoring barrier function and improving balanced cell turnover.

PRX PLUS: Tapping the Potential of Controlled Stress
PRX PLUS is made with ammonium trichloroacetate (ATCA), a TCA derivative, at a concentration that activates cellular renewal without visible peeling. This is not a simple chemical action at the surface: ATCA activates POMC-related pathways, stimulating:

Endogenous repair mechanisms
Skin lightening by melanin modulation
Tissue tone and elasticity through ACTH-related collagen stimulation
Coupled with homocysteic acid, an agonist of the NMDA receptor, PRX PLUS induces a controlled cellular stress condition, inducing regeneration as opposed to destruction.

Evidence from Clinical Practice
A 30-patient controlled study of three weekly PRX PLUS treatments demonstrated measurable improvement in:

Wrinkle depth: –40.4%
Skin roughness: –30.2%
Pore size: –46.5%
Sebum production: –18.6%
— with zero downtime, no noticeable peeling, and no side effects indicated.
These consequences cannot be accounted for by exfoliation alone. Instead, they are in line with a hormonal regulation of skin physiology, presumably mediated by POMC and downstream peptides.

Why This Is Important to Us as Doctors Historically, aesthetic procedures have been classified as mechanical, chemical, or thermal. PRX PLUS represents a fourth class: biochemical modulation through endogenous stress pathways.

Knowing the SSRS and the POMC enables us to:

Better predict patient responses

Tailor protocols according to skin type and sensitivity

Synergistically combine treatments (e.g., with LED or microneedling)

Moreover, this biochemical mechanism may explain why PRX PLUS is so well tolerated, even in phototypes IV–VI and during summer months.

A New Way to Think About Peels We are not just “peeling” layers anymore—we are engaging the skin’s own intelligent mechanisms for regeneration. PRX PLUS is a perfect example of this paradigm: a painless, topical protocol that communicates in the language of the epidermis—hormonal, not mechanical. As we shift towards physiology-friendly, non-invasive treatments, having an understanding of the stress-peptide axis provides us with a greater clinical explanation for what we see in practice.

References
Kimura A. et al. (2012). Effects of chemical peeling on the skin stress response system. Exp Dermatol.
Report_PRX_Plus.pdf, WiQo Clinical Data, 2023.
PRX PLUS Product Presentation, WiQo, 2024.