Acetyl Sh-Tetrapeptide-39

Acetyl Sh-Tetrapeptide-39 is a synthetic peptide — a short chain of amino acids — designed to work as a skin conditioning agent. Peptides are commonly used in skincare to communicate with skin cells and support various biological processes that contribute to skin health and appearance.

This particular peptide appears to function through acetylation-related pathways, which influence how cells regulate stress responses and maintain their structural integrity. By doing so, it may help support the skin's natural resilience and condition.

The ingredient works through acetylation regulation — a cellular process that controls how proteins behave and how cells respond to stress. By influencing acetylation pathways, the peptide may help regulate stress responses within skin cells, particularly in response to environmental damage.

Research suggests that this mechanism can support cell longevity and reduce the accumulation of cellular damage that occurs over time, though the specific effects in living skin remain an area of ongoing investigation.

This ingredient is typically incorporated into serums, moisturisers, and targeted treatments. Use as directed on the product label — it works best as part of a consistent routine rather than as an occasional treatment. It pairs well with other skin-conditioning ingredients and can be used alongside other active ingredients, though introduce new products one at a time if your skin is sensitive.