PROMISING PEPTIDES

Patrick Treacy explores peptides move into mainstream medicine, regenerative aesthetics and regulatory responsibility

Peptides have emerged as one of the most discussed and least consistently understood classes of compounds in contemporary aesthetic medicine.

These short chains of amino acids function as biological signalling molecules, regulating processes such as inflammation, metabolism, tissue repair, pigmentation, neuroendocrine signalling and skin regeneration.

Unlike traditional pharmacological agents that block or force pathways, peptides typically modulate endogenous physiological systems, offering a level of precision that is both appealing and potentially hazardous.

The recent success of GLP-1 receptor agonists has brought peptide therapeutics firmly into mainstream medicine. At the same time, increasing interest in regenerative and aesthetic peptides, many unlicensed or compounded, has created a challenging landscape for clinicians seeking to balance innovation with patient safety and professional responsibility.

THE GLP-1 PARADIGM: WHEN PEPTIDE MEDICINE WORKS

The clearest demonstration of peptide efficacy comes from GLP-1 receptor agonists such as semaglutide, now widely used in obesity and metabolic disease.

GLP-1 is an endogenous peptide hormone involved in appetite regulation, insulin sensitivity, and gastric emptying. Large randomised controlled trials have shown clinically meaningful and sustained weight loss, along with cardiometabolic benefits.¹ ²

From an aesthetic medicine perspective, GLP-1 analogues illustrate several important principles:

• Peptide therapies can be highly effective when rigorously tested ¹

• Safety profiles emerge only through large-scale, long-term trials ²

• Regulatory approval remains the critical safeguard against premature adoption ⁷ Newer investigational agents such as retatrutide, a triple-agonist peptide acting on GLP-1, GIP and glucagon receptors, may further expand metabolic applications, though these remain outside routine clinical use pending regulatory evaluation.³

REGENERATIVE PEPTIDES: PROMISE EXCEEDING EVIDENCE

Interest in peptides such as BPC-157 and TB-500 reflects a broader enthusiasm for regenerative medicine. Preclinical studies suggest roles in angiogenesis, tendon repair and wound healing, largely mediated through cellular migration and vascular signalling pathways. However, it is essential to emphasise that:

• Most data derive from animal or in-vitro studies

• High-quality human clinical trials are lacking

• Neither compound holds UK or EU regulatory approval ⁷ ⁸ Despite this, these peptides are increasingly discussed within sports medicine and aesthetic circles, often sourced from compounding pharmacies or international suppliers. Their popularity illustrates the growing gap between patient demand and evidence-based medicine.

PEPTIDES RELEVANT TO AESTHETIC DERMATOLOGY

GHK-Cu

Among peptides relevant to aesthetic practice, GHK-Cu stands out for its comparatively strong evidence base. This copper-binding peptide has demonstrated:

• Stimulation of collagen and glycosaminoglycan synthesis ⁴

• Enhanced wound healing ⁴

• Improved skin elasticity and texture ⁵

GHK-Cu is widely used in topical formulations and has supporting human and laboratory data, making it one of the more defensible peptides in dermatologic use. ⁵

Melanotan II

By contrast, melanotan II, a synthetic melanocortin analogue, highlights the risks of peptide misuse. While capable of inducing pigmentation, it has been associated with:

• Nausea and cardiovascular effects

• Unpredictable dosing

• Potential melanoma risk

Its widespread availability through unregulated international supply chains, particularly outside EU oversight, raises serious safety and medico-legal concerns⁷ .

NEUROENDOCRINE AND SLEEP-RELATED PEPTIDES

Oxytocin, a naturally occurring neuropeptide, has been studied for its effects on social bonding, trust and eye contact. Intranasal oxytocin has shown mixed results in conditions such as autism spectrum disorder and social anxiety. Outcomes appear highly context dependent, reinforcing the importance of patient selection and cautious interpretation.

Epitalon (epithalon), derived from pineal peptides, has been studied primarily in Eastern Europe for its effects on melatonin secretion and circadian regulation. Claims regarding antiaging and telomere modulation remain unproven in Western regulatory contexts.

METABOLIC, HORMONAL, AND LONGEVITY-ASSOCIATED PEPTIDES

Several peptides increasingly discussed in aesthetic and longevity medicine warrant brief mention:

• MOTS-c: a mitochondrial-derived peptide involved in metabolic regulation and insulin sensitivity ⁶

• Ipamorelin: a selective growth hormone secretagogue with limited clinical data

• Kisspeptin-10: a key regulator of the hypothalamic–pituitary– gonadal axis, with emerging reproductive applications While biologically plausible, these compounds currently lack sufficient evidence to justify routine aesthetic use.

REGULATION, SOURCING, AND PROFESSIONAL RESPONSIBILITY

A major challenge in peptide medicine lies in regulatory fragmentation. In the UK and EU, only licensed medicinal products are subject to robust quality, safety, and efficacy standards.⁷ Compounded peptides occupy a legal grey area, while grey-market products, often sourced internationally, carry risks of contamination, incorrect dosing, and biological unpredictability.⁸ Given their potency, peptides should not be treated as cosmetic adjuncts or lifestyle enhancers. Informed consent, documentation, and clear communication of uncertainty are essential.

CONCLUSION

Peptides represent a powerful and evolving class of biologically active compounds with genuine potential in medical aesthetics and regenerative practice. However, the gap between scientific promise and clinical proof remains substantial for many agents currently in circulation. For aesthetic clinicians, the imperative is clear: innovation must follow evidence, not precede it.

The success of GLP-1 therapies demonstrates what peptide medicine can achieve when guided by rigorous science and regulation. The challenge now is ensuring that the wider peptide landscape develops along the same path; measured, ethical and patient-centered.


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PATRICK TREACY

Professor Dr Patrick Treacy is a best-selling author and globally esteemed leader in aesthetic medicine, celebrated for all his contributions and international accolades. He was awarded ‘’Irish Man of The Year 2024’ for humanitarianism and outstanding contributions to aesthetic medicine. Dr Treacy’s innovative research has advanced patient safety by developing hyaluronidase protocols in aesthetic medicine.