Acetyl Tetrapeptide-5 is a synthetic cosmetic peptide consisting of four amino-acid residues with an acetyl group attached to the peptide structure. It is primarily used in skincare products designed to improve the appearance of under-eye puffiness, dark circles, and signs of fatigue, and is particularly common in eye creams, serums, and anti-aging formulations.
1. Basic profile
| Property | Information |
| INCI name | Acetyl Tetrapeptide-5 |
| Type | Synthetic tetrapeptide |
| Peptide length | 4 amino acids |
| Main cosmetic role | Skin-conditioning and anti-aging active |
| Primary application | Eye-area and facial skincare |
| Target concerns | Puffiness, tired-looking eyes, fine lines, loss of firmness |
| Typical formulation | Eye creams, eye serums, facial serums, gels |
| Origin | Produced by controlled chemical/biotechnological peptide synthesis |
| Solubility | Generally formulated in aqueous cosmetic systems, depending on the supplied grade |
| Stability | Formulation-dependent; pH, temperature, oxidation, and other ingredients can affect peptide stability |
2. What makes it different from ordinary peptides?
Acetyl Tetrapeptide-5 is a short signaling/functional peptide rather than a structural protein such as collagen. The acetyl modification can influence the molecule’s physicochemical properties and biological interactions.
Its small size is advantageous for cosmetic formulation, although skin penetration is still limited and highly dependent on the formulation.
3. Main cosmetic functions
Acetyl Tetrapeptide-5 is mainly associated with:
- Reducing the appearance of under-eye puffiness
- Improving the appearance of dark circles
- Supporting a smoother-looking eye contour
- Reducing the visible appearance of fine lines
- Improving the appearance of skin firmness and elasticity
- Providing skin-conditioning effects
It is therefore often positioned as an eye-contour peptide rather than simply a general anti-wrinkle peptide.
4. How it is thought to work
The peptide has been investigated for effects related to skin fluid balance, microcirculation, inflammation-related processes, and extracellular-matrix organization. Some commercial ingredient systems containing Acetyl Tetrapeptide-5 have reported improvements in the appearance of puffiness and dark circles.
However, it is important to distinguish ingredient-supplier studies from independent clinical evidence. Cosmetic claims can vary considerably depending on the peptide concentration, delivery system, formulation, and study design.
5. Where it is used
Typical applications include:
- Eye creams
- Eye gels
- Eye serums
- Anti-aging serums
- Firming creams
- Facial moisturizers
- Products targeting tired-looking skin
It is particularly useful when a formulation is designed around several complementary actives—for example, combining a peptide with humectants, antioxidants, soothing ingredients, and barrier-supporting ingredients.
6. Safety and limitations
Acetyl Tetrapeptide-5 is generally used as a cosmetic ingredient at relatively low concentrations and is not intended to function as a systemic drug. Its safety depends on the purity, concentration, formulation, and intended route of use.
A few important limitations:
- It should not be expected to permanently eliminate genetic or structural dark circles.
- Results from topical peptide products are generally subtle and gradual rather than dramatic.
- Puffiness caused by allergies, sleep deprivation, fluid retention, or medical conditions may not respond substantially.
- Evidence for some claimed mechanisms is less robust than the marketing literature may suggest.
7. Bottom line
Acetyl Tetrapeptide-5 is a short synthetic peptide primarily used in eye-care and anti-aging cosmetics. Its strongest commercial positioning is around the appearance of under-eye puffiness, dark circles, fine lines, and tired-looking skin. It is best considered a supportive cosmetic active rather than a standalone treatment for the underlying causes of these concerns.