What Is Acetylsalicyloyl Pentapeptide-33?
Acetylsalicyloyl Pentapeptide-33 is a lab-crafted molecule that joins two well known components: acetylsalicylic acid, the active part of aspirin, and a short chain of five amino acids known as Pentapeptide-33. When these two are reacted together they form a new ingredient that keeps some of aspirin’s soothing heritage while gaining the targeted skin benefits that modern peptides offer.
The idea of linking aspirin’s antioxidant edge with a peptide carrier started showing up in cosmetic research in the early 2010s, a time when brands were exploring ways to deliver familiar actives in gentler, skin-friendly forms. Advances in solid-phase peptide synthesis made it possible to string amino acids together with high purity, then bond them to small molecules like acetylsalicylic acid. The finished compound is made in controlled laboratory reactors where temperature and pH are carefully managed. After the reaction the mixture is purified, filtered and dried into a fine powder that dissolves easily in cosmetic bases.
You will most often spot Acetylsalicyloyl Pentapeptide-33 in leave-on products where ongoing contact with the skin lets it work steadily. Think lightweight serums, age-defying eye creams, daily moisturizers, overnight masks, spot treatments for dull areas and protective day lotions.
Acetylsalicyloyl Pentapeptide-33’s Cosmetic Benefits/Uses
This ingredient pulls double duty in a formula thanks to the properties it inherits from both aspirin and peptides.
- Antioxidant: It helps neutralize free radicals that form from UV exposure and pollution which can otherwise speed up the look of aging and dullness. By limiting this oxidative stress the ingredient supports a brighter, more even skin tone.
- Skin protecting: The peptide side of the molecule promotes a healthier skin barrier. A stronger barrier keeps moisture in and irritants out helping skin feel comfortable and resilient through the day.
Who Can Use Acetylsalicyloyl Pentapeptide-33
Most skin types can comfortably use this ingredient. Its peptide backbone makes it gentle enough for normal, dry and combination skin while the acetylsalicylic segment offers light soothing that can appeal to sensitive or redness-prone complexions. Oily or blemish-prone skin can also benefit since the molecule is lightweight and non-occlusive, meaning it will not sit heavily on pores.
Because the compound is fully synthetic and built from basic amino acids it is suitable for vegans and vegetarians. No animal-derived materials are used in its manufacture.
Pregnant or breastfeeding women are usually advised to be cautious with salicylates. Although the amount here is far lower than in medical products the safest course is to discuss any skincare containing Acetylsalicyloyl Pentapeptide-33 with a qualified healthcare provider. This content is for information only and is not medical advice.
The ingredient is not known to increase photosensitivity so it does not make skin more prone to sunburn. Daily sunscreen remains important for overall skin health, but no extra sun avoidance steps are required specifically because of this peptide-salicylate.
Potential Side Effects/Adverse Reactions
Reactions to topical Acetylsalicyloyl Pentapeptide-33 differ from one person to another. The points below outline potential issues that might occur even though most users will not experience them when the ingredient is formulated and used correctly.
- Mild stinging or tingling shortly after application
- Temporary redness or warmth, especially on very sensitive skin
- Dry patches if layered with multiple exfoliating acids or retinoids
- Allergic response in individuals with aspirin or salicylate sensitivity
- Contact dermatitis triggered by an accompanying ingredient in the finished product rather than the peptide itself
If you notice persistent irritation, swelling or any unexpected reaction discontinue use immediately and seek medical advice if symptoms do not quickly settle.
Comedogenic Rating
Rating: 1/5
Acetylsalicyloyl Pentapeptide-33 is a lightweight water-soluble powder that contains no greasy carriers or pore-blocking waxes, so it sits low on the comedogenic scale. The small amount of salicylate can even offer a mild skin-clearing effect. It is therefore generally suitable for people who are prone to acne or breakouts.
The final rating can rise if the peptide is blended into a very rich balm or occlusive base, so always look at the whole formula rather than the peptide alone.
Summary
Acetylsalicyloyl Pentapeptide-33 brings two main jobs to a formula: antioxidant defense that helps mop up free radicals and skin-protecting support that encourages a stronger barrier. It does this by pairing the soothing power of acetylsalicylic acid with a targeted five-amino-acid sequence that communicates with the skin’s own repair system.
Right now the ingredient is still a niche pick, most often seen in forward-thinking serums or eye creams rather than on every drugstore shelf. That said, interest in peptide hybrids keeps growing so its presence is likely to expand.
Overall safety is high for most users thanks to the gentle peptide backbone and low salicylate load. Anyone with a known aspirin sensitivity should steer clear and, as with any new skincare, a quick patch test is smart before diving into full-face use.