AccessPEP MUL

High-Performance Brightening Peptide for Visible Dark Spot Reduction

INCI Name: Methyl Undecenoyl Leucinate

AccessPEP MUL is a high-performance, oil-soluble peptide designed to brighten and even skin tone. Powered by Methyl Undecenoyl Leucinate, this lipoamino acid functions as an α-MSH antagonist to downregulate melanogenesis at its source. It effectively reduces the appearance of hyperpigmentation and dark spots and delivers excellent bioavailability in creams, serums, and targeted treatments.

Solubility Notes:

Oil-soluble. Incorporate into the oil phase of formulations; heat gently to aid dissolution. Suitable for anhydrous (water-free) systems and emulsions; performs well within a typical cosmetic pH range of ~4.5–6.5.

Perfect For These Applications

Other cosmetic uses possible—contact us for formulation guidance.

Brightening Serums & Facial Oils

Delivers the oil-soluble peptide deep into the skin in anhydrous or emulsion systems for potent, targeted dark spot correction.
Dark Spot Correctors & Treatments

Provides concentrated activity in targeted spot treatments to visibly fade discoloration and stubborn hyperpigmentation.
Anti-Aging & Brightening Creams

Combines powerful brightening with moisturizing bases to address uneven tone and signs of aging in a single product.
Evening Skincare & Night Treatments

Works synergistically with the skin’s overnight repair cycle to reduce melanocyte activity and promote a more uniform complexion.
Body Lightening Lotions

Targets hyperpigmentation on the body, including age spots on hands and sun spots on the décolletage, in nourishing lotion formats.
Foundation & Concealer Primers

Incorporates into color cosmetic bases to provide long-term brightening benefits alongside immediate coverage.

Performance & Formulation Insights for AccessPEP MUL

How AccessPEP MUL Brightens Skin

AccessPEP MUL features Methyl Undecenoyl Leucinate, a lipoamino acid that acts as a potent antagonist of the α-melanocyte-stimulating hormone (α-MSH). By interacting with the MC1R receptor on melanocytes, it competitively blocks α-MSH from initiating the pigmentation cascade. This upstream action downregulates key melanogenic genes including TYR (Tyrosinase), TRP-1, and TRP-2, thereby reducing melanin synthesis at its source. The result is a visible reduction in hyperpigmentation and dark spots and the promotion of a brighter, more uniform complexion. Its performance compares favorably with well-known brightening agents such as kojic acid and arbutin.

Technical Advantages & Formulation Guidelines

A key advantage of AccessPEP MUL is its oil solubility—uncommon for peptides—which supports excellent bioavailability, flexible formulation design, and enhanced delivery in both anhydrous systems and emulsions. Incorporate into the oil phase and heat gently to ensure full dissolution. It is broadly stable under typical cosmetic processing conditions and is compatible across common formulation pH ranges. Recommended usage level is 1–4%. For a comprehensive, multi-pathway approach to skin tone improvement, combine with complementary actives such as Vitamin C derivatives (antioxidants/tyrosinase modulation), niacinamide (melanosome transfer), or gentle AHAs (surface renewal).

Key Formulation Benefits

Potent α-MSH Antagonist: Targets the initiator of melanogenesis for precise, effective brightening action.
High Efficacy: Demonstrates strong performance on visible dark spots and overall tone compared to benchmarks like kojic acid and arbutin.
Oil-Soluble Peptide: Unique solubility enables use in facial oils, anhydrous serums, and the oil phase of emulsions for enhanced penetration.
Reduces Hyperpigmentation: Visibly fades sun spots, dark spots, and post-inflammatory hyperpigmentation.
Promotes Even Skin Tone: Helps achieve a brighter, more uniform, and luminous complexion.
Supports Sensitive-Skin Formulations: Features soothing, anti-inflammatory properties to help minimize the risk of PIH.

Heading #1
Benefits	Brightening & Skin Lightening, Dark Spot Reduction, Even Skin Tone, Tyrosinase Inhibition
INCI Name	Methyl Undecenoyl Leucinate
Usage Rate	1%-4%
Active Type	Brightening Peptides, Peptides
Solubility	Oil-Soluble
Application Area	Body, Face
Physical Form	Powder
Certifications	Cruelty-Free, Vegan

Frequently Asked Questions About AccessPEP MUL

The recommended usage level is 1% to 4%, depending on product format and desired intensity.

AccessPEP MUL blocks the α-MSH signal upstream at the MC1R receptor to reduce melanin synthesis at its source. Vitamin C typically modulates tyrosinase activity and provides antioxidant support, while Niacinamide helps inhibit melanosome transfer. They can be combined for multi-pathway brightening.

Yes. It is a lipoamino acid (a modified peptide) formed by grafting a fatty acid (undecylenoyl) to an amino acid (leucinate), conferring oil solubility and enhanced skin penetration.

As an oil-soluble active, it is less pH-sensitive and performs well within typical cosmetic ranges, approximately pH 4.5–6.5.

Yes. It is generally well tolerated and offers anti-inflammatory benefits, making it suitable for sensitive-skin brightening formulas.

Add it to the oil phase and heat gently with oils/lipids until fully dissolved. It is also suitable for cold-process, anhydrous oil-based serums.

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