Dipeptide-40: 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 27, 2025
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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 Dipeptide-40?

Dipeptide-40 is a lab made peptide built from two amino acids, leucine and lysine. Because it is synthetic, manufacturers can control its purity and stability far better than a naturally sourced alternative. The beauty industry’s interest in short peptides took off in the late 1990s when researchers learned these tiny protein fragments could signal the skin to look and feel healthier. Dipeptide-40 joined this family as chemists searched for simple peptide pairs that provide a smooth, hydrated feel without a heavy texture.

Production usually relies on solid phase peptide synthesis, a step-by-step process that adds one amino acid at a time to a growing chain. Once the sequence is complete, the peptide is cleansed of by-products, filtered, then dried into a fine powder. Formulators dissolve this powder in water or a light solvent before blending it into finished products.

You will most often see Dipeptide-40 in leave-on items that aim to soften and refresh the skin. It shows up in lightweight serums, daily moisturizers, anti-aging creams, soothing after-sun gels, sheet masks and eye treatments where a non-greasy feel is essential.

Dipeptide-40’s Cosmetic Benefits/Uses

When added to a formula in the right concentration this peptide mainly works to condition the skin, making it feel smoother and appear more supple. Dipeptide-40 helps support the skin’s surface so it can hold moisture better which in turn can soften the look of fine lines and dry patches. The result is a comfortable, well-hydrated finish that pairs nicely with both simple hydrating routines and more advanced anti-aging regimens.

Who Can Use Dipeptide-40

Dipeptide-40 suits most skin types including dry, normal, combination and oily skin because it feels light and focuses on hydration rather than heavy occlusion. Sensitive skin also tends to tolerate it well since it lacks common irritants such as fragrance or acids, though very reactive skin should still proceed carefully if the overall formula contains other actives.

The peptide is synthesized in a lab without any animal-derived ingredients so it fits vegan and vegetarian lifestyles. Its production does not rely on animal testing in regions that enforce modern cruelty-free standards, although consumers should always verify the finished brand’s stance on animal testing for full peace of mind.

Current research offers no evidence that Dipeptide-40 poses a special risk for pregnant or breastfeeding women when used in typical cosmetic concentrations. Even so this is not medical advice and anyone who is pregnant or nursing should share their planned skincare routine with a qualified healthcare provider for personalized guidance.

Dipeptide-40 does not make skin more sensitive to sunlight so there is no added risk of photosensitivity. Normal daily sun protection habits are still encouraged to protect overall skin health.

Potential Side Effects/Adverse Reactions

Responses to topical Dipeptide-40 vary from person to person. The issues listed below are possible but uncommon when the ingredient is formulated and used correctly.

  • Mild redness or warmth in very sensitive skin during initial uses
  • Temporary itching if applied to compromised or highly irritated areas
  • Allergic contact dermatitis in the rare event of a true peptide allergy
  • Stinging or tingling when layered with strong exfoliating acids or retinoids in the same routine

If any persistent discomfort, swelling or rash develops stop using the product and consult a healthcare professional for assessment and treatment

Comedogenic Rating

Rating: 0 out of 5. Dipeptide-40 is a tiny, water-loving molecule that sits on the surface, does not leave an oily film and has no known pore-clogging properties. Most formulas that feature it are lightweight serums or gels with minimal oils, further lowering any clogging risk. Suitable for acne-prone or breakout-prone skin. Unless the overall product is packed with heavy waxes or butters, this peptide should not add to congestion.

Summary

Dipeptide-40 is a lab made pair of amino acids that mainly conditions the skin, helping it feel smoother and stay hydrated. By supporting the outer layer so it holds water better, it can soften the look of fine lines and dry spots while keeping the finish light.

The peptide is still more of a niche choice than a headline ingredient, yet brands that focus on gentle hydration and modern peptide tech are starting to include it in serums, moisturizers and eye creams.

Overall safety is high, with very few reports of irritation or allergy at normal use levels. As with any new skincare product it is smart to patch test first to check personal tolerance before applying to a larger area.

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