Subject: Leave-in Hair Serum Formulation Guidance

Dear R&D,

Regarding the requested formulation for a leave-in hair serum with the specified ingredients and percentages:

Ingredients:

• Pro Polymer Silk: 4%
• Hydro Gel: 3%
• Poly-Conditioner Pro 400mPa.s: 2%
• 1,3-Propanediol (natural): 1%
• CTAC: 1%
• BTAC: 2%
• GuarCat weight-less: 0.5%
• Creatine 100: 0.5%
• Biotin Express: 1%
• Pure Keratin: 1%
• Condi-B5: 2%
• Argan Oil: 1%
• Ectoin: 0.5%
• Water: q.s. to 100% (adjust based on total of other ingredients)
• Preservative: q.s. (according to supplier's recommendation)

Total of listed ingredients = 19%. Water will be approximately 81%.

Recommended Mixing Procedure:

1. In a suitable container, combine Water, 1,3-Propanediol, Hydro Gel, GuarCat weight-less, Creatine 100, Biotin Express, Pure Keratin, and Ectoin. Mix thoroughly until all powdered ingredients are dissolved and GuarCat is fully hydrated. Gentle heating (e.g., 40-50°C) may help in dissolving some ingredients and hydrating GuarCat.
2. Add Poly-Conditioner Pro 400mPa.s, CTAC, BTAC, and Condi-B5 to the mixture from step 1. Continue mixing until homogeneous.
3. Slowly add Pro Polymer Silk while mixing continuously. Mix until the desired serum viscosity is achieved.
4. Add Argan Oil and mix until well dispersed.
5. If heated, cool the mixture down.
6. Add your chosen preservative according to the supplier's recommended usage rate. Add fragrance if desired.
7. Check and adjust the pH of the final product to a suitable range for hair (typically pH 4.5-5.5) using a mild acid or base if necessary.

Please note: This formulation requires a suitable preservative system to prevent microbial growth, as it contains a significant amount of water and various ingredients that can support growth.