Myristoyl Pentapeptide-4, Biotinoyl Tripeptide-1 & Acetyl Tetrapeptide-3: Hair & Skin Regeneration Complex
What Are Peptides? A Brief Primer
Peptides are short chains of amino acids—the building blocks of proteins. In the human body, proteins like collagen, elastin, and keratin are essential for maintaining the structure and function of skin, hair, and nails. However, these large protein molecules are too big to penetrate the skin when applied topically. Peptides, being much smaller, can penetrate the stratum corneum and deliver targeted signals to cells .
Once delivered, peptides act as signaling molecules, instructing cells to perform specific functions such as producing more collagen, synthesizing keratin, or proliferating. This makes them highly targeted, biologically active ingredients with excellent safety profiles .
Based on their mechanism of action, cosmetic peptides can be classified into:
Signal peptides: Stimulate the production of extracellular matrix components (collagen, elastin, keratin)
Carrier peptides: Deliver trace elements (like copper) to specific sites
Neurotransmitter inhibitor peptides: Relax facial muscles to Reduce wrinkles
The three peptides featured in this article are primarily signal peptides—they send specific signals to cells to promote hair growth, strengthen follicles, and regenerate tissue .
Peptide 1: Myristoyl Pentapeptide-4 – The Keratin Activator
Myristoyl pentapeptide-4 is a synthetic peptide composed of five amino acids with the sequence Lys-Thr-Thr-Lys-Ser (KTTKS) , modified with a myristoyl fatty acid chain to enhance skin penetration . Its molecular weight is approximately 774 g/mol, and its CAS number is 1392416-25-9 .
Primary Mechanism: Keratin Gene Activation
The primary function of myristoyl pentapeptide-4 is to activate keratin gene expression. Keratin is the primary structural protein that makes up hair, skin, and nails. By stimulating the transcription and translation of keratin genes, this peptide promotes the production of more keratin, resulting in stronger, more elastic, and healthier hair fibers .
Key Research Findings:
- Keratin Synthesis: At concentrations of 10-40 μM over 48 hours, myristoyl pentapeptide-4 specifically targets keratin, activating both its transcription and translation .
- Cell Proliferation and Migration: Studies at 0-25 μM over 24 hours demonstrate that this peptide promotes the proliferation of HaCaT cells (human keratinocytes) and enhances the migration of human dermal papilla cells (HDPCs)—the cells at the base of hair follicles responsible for hair growth regulation .
- Wound Healing: Beyond hair applications, myristoyl pentapeptide-4 also promotes wound healing and skin repair, making it valuable in regenerative skincare .
Applications in Cosmetics:
Myristoyl pentapeptide-4 is widely used in eyelash growth serums, hair growth treatments, and Anti-aging skincare. A patent for a composition promoting eyelash growth specifically lists myristoyl pentapeptide-4 as a key active ingredient .
Peptide 2: Biotinoyl Tripeptide-1 – The Follicle Anchor
Biotinoyl tripeptide-1 (also known as Biotinoyl Tripeptide-1) is a synthetic peptide that combines biotin (vitamin B7) with a tripeptide sequence. The INCI name is often listed as Biotinoyl Tripeptide-1, and it is available in various concentrations and delivery systems, such as SpecPed® BT1 (0.1%) .
Primary Mechanism: Extracellular Matrix Reinforcement
Biotinoyl tripeptide-1 works by stimulating the synthesis of extracellular matrix components within the hair follicle environment, particularly type IV collagen and laminin 5. These structural proteins form the basement membrane that anchors the hair follicle within the dermis .
Key Research Findings:
- Hair Anchorage: By promoting the synthesis of type IV collagen and laminin 5, this peptide helps delay hair follicle aging and improves the structural integrity of the follicle, ensuring better anchorage and reduced hair fall .
- Tissue Repair Gene Activation: Biotinoyl tripeptide-1 can activate the expression of tissue repair genes, which is beneficial for skin structure reconstruction and wound healing .
- Cell Proliferation and Differentiation: It promotes cell proliferation and differentiation, stimulating hair growth and leading to longer, stronger eyelashes and eyebrows .
Applications in Cosmetics:
This peptide is recommended for use in products targeting hair growth, strengthening, and anti-hair loss. It is particularly valued in eyelash and eyebrow serums for its ability to help lashes "reach their full potential" .
Peptide 3: Acetyl Tetrapeptide-3 – The Cellular Matrix Builder
Acetyl tetrapeptide-3 is a synthetic tetrapeptide (four amino acids) that has been modified with an acetyl group to improve stability and penetration. It is often featured in formulations targeting hair regrowth and follicle health.
Primary Mechanism: Dermal Papilla Support and Matrix Anchoring
Acetyl tetrapeptide-3 works by promoting the regrowth of hair follicles and building stronger cellular matrices around the dermal papilla—the specialized structure at the base of the hair follicle that controls hair growth cycles. By strengthening this matrix, the peptide ensures that hairs are better anchored, reducing the chance of fallout .
Key Research Findings:
- Collagen III Stimulation: Acetyl tetrapeptide-3 has been shown to stimulate the synthesis of collagen III in hair follicles. Collagen III is an elastic, fibrous protein essential for the development and maintenance of healthy hair follicles .
- Cellular Matrix Building: It helps build stronger cellular matrices around the dermal papilla, which means that lashes and brows will be better anchored, with less chance of fallout .
- Regrowth Promotion: The peptide actively promotes the regrowth of hair follicles, making it valuable for both prevention and treatment of thinning .
Applications in Cosmetics:
Acetyl tetrapeptide-3 is a key ingredient in eyelash and eyebrow enhancing serums, often combined with other peptides and botanical extracts for synergistic effects .
The Synergy: Why These Three Peptides Work Better Together
Individually, each of these peptides offers significant benefits. However, scientific research has demonstrated that when combined, they produce a synergistic effect that is greater than the sum of their parts.
Scientific Validation: The CAM-NLP Study
A groundbreaking study published in 2022 developed a nanoliposome system that co-encapsulated Copper peptide, Acetyl tetrapeptide-3, and Myristoyl pentapeptide-4 (CAM-NLPs) .
The key findings of this study include:
| Parameter | Result |
| Cell Proliferation | CAM-NLPs remarkably promoted proliferation of HaCaT (keratinocytes) and HDPCs (dermal papilla cells) |
| Cell Migration | Boosted migration ability of HDPCs |
| Protein Secretion | Increased secretion of Collagen III, VEGF, and bFGF from HDPCs |
| Gene Expression | Up-regulated VEGF and β-catenin; down-regulated TGF-β1 in C57BL/6 mice |
| Penetration | Enhanced transdermal delivery specifically through the hair follicle pathway |
The study concluded that "CAM-NLPs are effective transdermal co-delivery nanocarrier for alleviating hair loss... with hair growth promotion, high safety and great potential" .
The Mechanism of Synergy:
When combined, these three peptides target different but complementary aspects of hair and follicle health:
Myristoyl Pentapeptide-4 activates keratin production, building stronger hair fibers from the inside out.
Acetyl Tetrapeptide-3 stimulates collagen III production, strengthening the dermal papilla and the matrix that anchors the follicle.
Biotinoyl Tripeptide-1 reinforces the basement membrane with type IV collagen and laminin 5, ensuring optimal anchorage.
This multi-targeted approach ensures that every aspect of hair health is addressed—from the structural protein (keratin) to the supporting matrix (collagen III, laminin 5) to the anchoring mechanisms (type IV collagen) .
Applications in Cosmetics and Personal Care
- Eyelash and Eyebrow Serums
This is the most prominent application. These three peptides are star ingredients in lash and brow enhancing serums, where they work together to promote longer, thicker, fuller lashes and brows within 4-6 weeks of consistent use .
The typical formulation includes:
Acetyl Tetrapeptide-3: 1 mg per 10 mL
Biotinoyl Tripeptide-1: 0.066 mg per 10 mL
Myristoyl Pentapeptide-4: Often used at similar concentrations
These serums are typically applied once or twice daily along the upper and lower lash lines and along the natural brow line .
The same peptides that strengthen lashes are equally effective for scalp hair. They are incorporated into: Hair growth serums and tonics Scalp treatment sprays Leave-in conditioners for thinning hair Shampoos and conditioners for fine or aging hair |  |
- Anti-Aging Skincare
Beyond hair applications, these peptides—particularly myristoyl pentapeptide-4—are also valued for their skin regenerative properties, including wound healing and collagen synthesis .
Safety and Formulation Considerations
Safety Profile:
Non-irritating and non-sensitizing at recommended use levels
Suitable for sensitive skin and eye area applications
No known systemic toxicity with topical use
Formulation Guidelines:
| Peptide | Typical Use Level | Solubility | Notes |
| Myristoyl Pentapeptide-4 | 0.001% - 0.01% | Water-soluble | Heat-sensitive; add at cool-down phase |
| Biotinoyl Tripeptide-1 | 0.0001% - 0.001% | Water-soluble | Often supplied in solution (e.g., 0.1% active) |
| 0.001% - 0.01% | Water-soluble | Stable at pH 4-7 |
Key Considerations:
Delivery Systems: Peptides face challenges with skin penetration due to the stratum corneum barrier. Advanced delivery systems such as liposomes, niosomes, and nanoliposomes can significantly enhance peptide delivery to target cells .
- Temperature Sensitivity: Peptides are heat-sensitive and should be added to formulations during the cool-down phase (below 40°C / 104°F).
- Synergy with Other Ingredients: These peptides work well with panthenol (pro-vitamin B5), botanical extracts (e.g., apple fruit extract, clover flower extract), and other hair-growth ingredients .
Clinical Results and Consumer Expectations
Products containing this tri-peptide complex typically deliver visible results within a specific timeframe :
| Timeline | Expected Results |
| 4-6 weeks | Noticeable improvement in lash/brow length and thickness |
| 8-12 weeks | Full improvement in density and strength |
| 3 months | Optimal results with continued maintenance |
It is important to note that results can vary based on individual factors, formulation concentrations, and consistency of use.
Conclusion: The Future of Peptide-Based Hair and Skin Care
Backed by scientific research, including the CAM-NLP study demonstrating enhanced delivery and efficacy, this tri-peptide complex has earned its place in premium lash serums, hair growth treatments, and regenerative skincare products .