Pentapeptide-18Cosmetic ingredient
Pentapeptide-18, often marketed as Leuphasyl, is used in cosmetics for expression lines. Its proposed mechanism is inspired by signalling pathways involved in the release of neurotransmitters.
What is Pentapeptide-18?
Pentapeptide-18, also sold as the cosmetic ingredient Leuphasyl, is a short peptide used in products targeting the appearance of expression lines. It is a topical cosmetic ingredient, not an injectable muscle relaxant. 1 3
How it works
Its proposed action involves enkephalin-like signalling and neurotransmitter release. Whether a finished cream delivers enough peptide to the relevant target is a separate question from activity predicted in a model. 2 3
Effects studied
What does the evidence show?
The retained references include cosmetic and mechanistic research. Combination-product results and computational work should be kept separate from direct human evidence for this ingredient.
The proposed mechanism
The peptide is described in relation to enkephalin-like signalling. That provides a hypothesis about how chemical communication between cells might be influenced. Whether a topical preparation reaches the intended target, remains active and produces a visible difference are further questions that the mechanism alone cannot answer.
What a model can contribute
Computational studies can predict possible interactions and help researchers decide which experiments to run. They do not show that a product works in human skin. Likewise, a laboratory response does not establish the amount or duration of a cosmetic effect in everyday use. 2
Combination products complicate attribution
A formula may combine pentapeptide-18 with retinol, other peptides and a moisturising base, all of which can affect the outcome. A favourable result for the combination cannot establish whether this peptide adds a meaningful benefit without a comparison that isolates its contribution. 4
A useful claim stays concrete
A claim of an injection-like effect goes beyond describing the appearance change measured with a tested preparation. Sensitivity also matters, particularly when a formula contains other active ingredients. A peptide product can still irritate skin and may not suit every skincare routine.
Safety & status
Irritation and tolerability depend on the whole formulation, including other active ingredients and the base. A favourable ingredient description does not establish that every product is suitable for sensitive skin.
Country and product status
This page describes a cosmetic ingredient and its research context. Permitted claims and product availability in Germany and Switzerland need a local check. An ingredient listing does not establish approval to treat a medical condition.
Frequently asked questions
Is this the same as Botox?
No. A topical peptide cream and an injected medicine differ in delivery, target exposure and clinical evidence.
Does a study of a multi-ingredient cream prove this peptide works?
It evaluates that cream. Retinol, other peptides and moisturising ingredients can contribute, so the effect cannot automatically be assigned to pentapeptide-18. 4
Sources
This entry was rewritten from our research archive. References below are reading leads unless a completed check is explicitly noted; a full independent evidence and regulatory review is still pending.
- Pentapeptide-18: www.mdpi.com reference Reference or product information · Retained archive reference; not independently checked for this draft.
- Pentapeptide-18: paper 10.1016/j.compbiolchem.2026.108952 Research reference · Retained archive reference; not independently checked for this draft.
- Pentapeptide-18: www.specialchem.com reference Reference or product information · Retained archive reference; not independently checked for this draft.
- Pentapeptide-18: paper 10.3390/life14101212 Research reference · Retained archive reference; not independently checked for this draft.
Research provenance
This name was discovered in the Superpower peptide index, archived 26 October 2026. Its ratings and reviewer attribution have not been adopted as our own. The archive informed this original editorial draft; independent source review is still pending.