Tripeptide-39: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 30, 2025
Share:
Inside this article:

We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Tripeptide-39?

Tripeptide-39 is a lab made peptide built from three amino acids: alanine, leucine and proline. Because it is synthetic there is no plant or animal source to harvest which helps with consistency and purity. Peptides started gaining attention in skin care in the early 2000s when researchers found they could signal skin to look and feel healthier. Tripeptide-39 was developed during this wave of innovation to offer targeted skin conditioning in a stable form. Creating it involves solid-phase peptide synthesis, a step-by-step method that links the amino acids in a specific order, followed by purification to remove any unwanted fragments. The finished ingredient is a fine powder that dissolves easily in water based formulas. You will most often see Tripeptide-39 in anti-aging serums, firming creams, sheet masks and eye treatments where brands want to boost skin softness and suppleness without heavy oils or waxes.

Tripeptide-39’s Cosmetic Benefits/Uses

Tripeptide-39 is added to formulas mainly for one key purpose that makes skin care feel and look better.

Skin conditioning: This peptide helps the surface of the skin hold on to moisture so it feels smoother and more flexible. By supporting a well-hydrated barrier it can soften the look of fine lines and give the complexion a fresher appearance.

Who Can Use Tripeptide-39

Tripeptide-39 is generally well suited to all skin types including dry, normal, combination and oily because it conditions without leaving a greasy film. Sensitive skin usually tolerates it too since it lacks common irritants like fragrance or essential oils, though very reactive skin should watch for any personal triggers in the full formula.

Because this peptide is made entirely in a lab and contains no animal derived material it is considered vegan and vegetarian friendly. There is no need for animal by-products at any step in its production.

Pregnant or breastfeeding individuals can typically use products with Tripeptide-39 as no data suggests a specific risk. That said this is not medical advice and anyone expecting or nursing should have their doctor review any skincare routine to be extra safe.

Tripeptide-39 does not make skin more sensitive to sunlight so it is not classed as a photosensitiser. Standard daily SPF is still recommended for overall skin health.

Potential Side Effects/Adverse Reactions

Responses to topical Tripeptide-39 differ from person to person. The following list covers potential side effects even though most users will not experience them when the ingredient is used correctly in a well formulated product.

  • Mild redness or stinging
  • Itchy patches in individuals with very sensitive skin
  • Contact dermatitis if combined with other irritating ingredients
  • Allergic reaction in the rare case of a specific peptide allergy

If any irritation or unexpected reaction occurs stop using the product and consult a healthcare professional for guidance.

Comedogenic Rating

Tripeptide-39 has a comedogenic rating of 0. It is water soluble and contains no heavy oils, waxes or fatty acids that could clog pores, so it is considered non-comedogenic. This makes it generally suitable for people who are prone to acne or regular breakouts. Keep in mind the full formula still matters; rich creams or occlusive ingredients paired with the peptide could alter how pore friendly the finished product feels.

Summary

Tripeptide-39 is mainly a skin conditioning peptide that helps the surface hold moisture so skin feels softer and looks smoother. By reinforcing the skin’s water balance it can give a fresher more flexible appearance and reduce the look of fine lines.

While peptides like Matrixyl get more press, Tripeptide-39 is quietly gaining fans among brands that target lightweight hydration and firming. It blends easily into serums, masks and eye creams without changing texture or scent, which makes formulating straightforward.

Safety wise this ingredient is well tolerated by most skin types, including sensitive and acne prone skin. Side effects are uncommon and usually mild. As with any new product it is smart to do a quick patch test first to be on the safe side and spot any personal sensitivities early.

Was this article helpful?
More from Glooshi:
ADVERTISEMENT
Get all our top headlines in beauty.
Delivered right to your inbox each week. Zero spam, all goodness, opt-out at anytime.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Get the latest beauty news, top product recommendations & brand-exclusive discount codes direct to your inbox.
Send good feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Send bad feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Search