Review of Your Anti-Aging Serum Formula for Oily Skin

Thank you for sharing your anti-aging serum formula for oily skin. It includes a good selection of active ingredients targeting signs of aging and oiliness. Here is a review of your formula and answers to your questions:

1. Ingredient Compatibility

The ingredients you have chosen are generally compatible in a water-based serum formulation. Most are water-soluble and can be combined.

• Pro Polymer and Zinc PCA: Pro Polymer is designed to be electrolyte resistant, but the presence of electrolytes like Zinc PCA can affect its thickening ability and may require a higher concentration of Pro Polymer and a specific mixing order (adding electrolytes after the gel is formed). Your proposed mixing method addresses this.
• pH Levels: The optimal pH ranges for your ingredients generally overlap. Aiming for a final pH between 4.0 and 6.0 would be ideal, especially for the solubility and efficacy of Zinc PCA.
• High Active Concentrations: The formula includes very high concentrations of Pitera (60%) and Repair Activator (20%). While these can be effective, such high levels might make the serum feel heavy or slightly sticky on the skin, which might be a consideration for oily skin types.

2. Mixing Method

Your proposed mixing method is appropriate, especially for a home formulation without specialized equipment:

1. Mixing Pitera and Pro Polymer first to form the gel base is a good approach. Remember to sprinkle the Pro Polymer powder onto the liquid (Pitera) and stir slowly to allow it to hydrate and thicken without creating clumps or damaging the polymer structure.
2. Adding the other water-soluble ingredients (Repair Activator, Ectoine, Panthenol B5, Pure-EGCG, Dimethyl Isosorbide) next is suitable.
3. Adding DMAE and Zinc PCA last is correct. Zinc PCA is an electrolyte that should be added after the gel is formed, and DMAE should be added in the final step below 40°C.

Ensure thorough but gentle stirring at each step to ensure everything is well incorporated.

3. Pro Polymer Amount

You are using Pro Polymer at 2%. The recommended usage rate for a general gel texture is around 0.8%. However, since your formula contains an electrolyte (Zinc PCA) and high concentrations of other ingredients that contribute to viscosity (like Pitera and Repair Activator), 2% is a reasonable amount to achieve a serum consistency that is not too watery. It is within the recommended range (0.5-5%) and should provide adequate thickening given the formula composition.

4. Necessity of DMI

Dimethyl Isosorbide (DMI) is a penetration enhancer. While your active ingredients are water-soluble and can dissolve without DMI, including DMI at 3% can help improve the delivery and absorption of these active ingredients into the skin. This can potentially enhance their efficacy. It is not strictly necessary for the formula to be stable or mixable, but it serves a beneficial function in improving the performance of the active ingredients like Zinc PCA, Ectoine, Panthenol, and others in your formula.

Overall, your formula is well-designed with potent anti-aging and oil-controlling ingredients. Pay attention to the final texture due to the high active concentrations and ensure the pH is in the optimal range after mixing.