Hair loss and thinning affect a significant proportion of the adult population, and the demand for effective topical actives in this category continues to grow. Peptides offer a mechanistically targeted approach to hair biology — one that goes beyond the non-specific stimulation of older actives such as minoxidil. This guide covers the key hair-active peptides in the UNIPEP range, with a focus on mechanism and formulation practice.

The Biology of Hair Loss: A Formulator's Framework

Effective formulation begins with understanding the target. Hair loss (alopecia) has multiple causes, but the most common — androgenetic alopecia and telogen effluvium — share a common pathway: progressive miniaturisation of the hair follicle, shortening of the anagen (growth) phase, and weakening of the dermal papilla.

The dermal papilla is the key target for topical hair actives. It is a cluster of specialised fibroblasts at the base of the follicle that controls follicle cycling, hair fibre diameter, and the duration of the anagen phase. Peptides that stimulate dermal papilla activity, strengthen the anchoring of the hair fibre, or extend the anagen phase address the root cause of follicle miniaturisation.

Biotinoyl Tripeptide-1: Anchoring the Hair Fibre

INCI name: Biotinoyl Tripeptide-1

Biotinoyl Tripeptide-1 is a biotinylated tripeptide that targets the interaction between the hair fibre and the dermal papilla. Its mechanism centres on the upregulation of laminin-5 and collagen IV — glycoproteins that form part of the anchoring complex connecting the hair bulb to the basement membrane of the dermal papilla.

When laminin-5 expression is reduced — as occurs in androgenetic alopecia — the hair fibre becomes less securely anchored, leading to premature shedding. Biotinoyl Tripeptide-1 stimulates laminin-5 and collagen IV synthesis, reinforcing this anchoring complex and reducing premature hair loss. In addition, it has a dual mechanism: inhibition of 5-alpha-reductase activity and reduced DHT-androgen-receptor binding, addressing the hormonal component of androgenetic alopecia at the follicular level.

Recommended use level: 0.001–0.1% as pure powder (as supplied)
Optimal pH: 5.0–7.0
Solubility: Water-soluble; add below 40°C

Acetyl Tetrapeptide-3: Extending the Anagen Phase

INCI name: Acetyl Tetrapeptide-3

Acetyl Tetrapeptide-3 acts on the dermal papilla through a different mechanism: it stimulates the production of extracellular matrix proteins — specifically VEGF (Vascular Endothelial Growth Factor), collagen types III, IV and VII, and laminin — within the dermal papilla itself. This strengthens the structural integrity of the papilla and supports the signalling environment that maintains the anagen phase.

VEGF upregulation is particularly significant: it promotes the vascularisation of the dermal papilla, improving nutrient delivery to the actively dividing matrix cells of the hair bulb.

UNIPEP HairForce contains Biotinoyl Tripeptide-1 and Acetyl Tetrapeptide-3 as its active peptide components, delivering complementary mechanisms — anchoring reinforcement and anagen extension — in one ingredient.

Recommended use level: 0.001–0.1% as pure powder (as supplied)
Optimal pH: 5.0–7.0
Solubility: Water-soluble; add up to 45°C

Myristoyl Pentapeptide-4: Hair Strengthening

INCI name: Myristoyl Pentapeptide-4

Myristoyl Pentapeptide-4 is a lipopeptide — the myristoyl (C14 fatty acid) chain provides lipophilicity for enhanced penetration — that stimulates keratin gene expression and the synthesis of key extracellular matrix proteins including laminin and collagen I. These actions support hair fibre strength and follicle structural integrity.

UNIPEP LashBoost contains Myristoyl Pentapeptide-4 as its active peptide component, formulated for use in hair serums and multi-functional scalp products.

Note: Myristoyl Pentapeptide-17 is the peptide used for eyelash growth applications (indicative use level 0.001–0.01% as pure powder). Confirmation of the specific INCI in UNIPEP LashBoost is pending — please refer to the current TDS.

Recommended use level: 0.001–0.01% as pure powder (as supplied)
Optimal pH: 5.0–7.0
Solubility: Slightly soluble; use a solubiliser such as Tween-20 at typical use levels. Add up to 45°C.

Formulating Hair Peptide Products

Vehicle Selection

Hair peptide actives are most effective when delivered in vehicles that maximise contact time with the scalp or lash line. Recommended formats include:

• Leave-on scalp serums: Highest efficacy due to prolonged contact. Typically water-based with 1–5% humectants (glycerin, propylene glycol) to support skin penetration.
• Scalp tonics: Alcohol-based or hydroalcoholic formulations. Alcohol can enhance penetration but may cause irritation at high concentrations; keep ethanol below 20% for leave-on scalp products.
• Lash serums: Typically water-based, low-viscosity formulations applied with a fine brush or wand applicator. pH 5.5–6.5 is optimal for periorbital use.
• Conditioners and masks: Lower efficacy due to rinse-off format, but can contribute to overall hair health. Use at the higher end of the recommended range.

Combination Strategies

Hair peptide actives combine well with:

• Caffeine: Inhibits phosphodiesterase, increasing cAMP levels in dermal papilla cells and stimulating follicle activity. Complementary mechanism to peptide actives.
• Niacinamide: Improves scalp microcirculation and has anti-inflammatory properties. Compatible with all peptides listed here.
• Zinc PCA: Inhibits 5α-reductase, reducing DHT production at the follicle level. Addresses the hormonal component of androgenetic alopecia.
• Biotin (free): Synergistic with Biotinoyl Tripeptide-1 for keratinocyte support.

Stability Considerations

All peptides listed here are stable in the pH range 5.0–7.0. Avoid formulating in strongly acidic systems (pH < 4.5) or alkaline systems (pH > 8.0). Add to the water phase at the temperatures specified above. Incompatibilities include strong acids, strong bases, and strong oxidising agents; confirm by stability testing.

Storage: Store peptide powders at 2–8 °C in tight containers. Shelf life is 24 months under these conditions.

Conclusion

Biotinoyl Tripeptide-1, Acetyl Tetrapeptide-3, and Myristoyl Pentapeptide-4 represent three distinct and complementary mechanisms for addressing hair thinning at the follicular level. For formulators developing evidence-based hair care actives, these peptides offer a mechanistically targeted foundation.

UNIPEP HairForce and UNIPEP LashBoost are available with full Technical Data Sheets. Contact Unikema srl to request samples or formulation support.