Formulation Compatibility Analysis

The combination of ingredients you've proposed is generally compatible in a water-based system like Aloe Vera Gel. Many of these ingredients are commonly used together in skincare formulations targeting concerns like acne, oiliness, hydration, and skin barrier support.

• Vitamin B3 (Niacinamide) 10%: You mentioned a previous comment about the 5% usage limit. While 5% is a common and effective concentration with low risk of irritation, Niacinamide can be used up to 10%. High-purity grades, such as Safe-B3™ or Extreme-B3™, are specifically designed to minimize the flushing or redness sometimes associated with higher concentrations of standard Niacinamide. However, even with high-purity grades, individual skin sensitivity varies, so patch testing is highly recommended, especially at 10%. Niacinamide is water-soluble and works well in the typical pH range for this type of formulation.
• Vitamin B5 (Panthenol) 5%: Panthenol is a great humectant and skin-conditioning agent. It is water-soluble and compatible with the other ingredients. At 5%, it provides good moisturizing and soothing benefits. Higher concentrations can sometimes feel slightly sticky, but this depends on the overall formulation.
• Centella Asiatica Extract 5%: Centella Asiatica Extract (often referred to as CICA) is known for its soothing, anti-inflammatory, and wound-healing properties, which are beneficial for acne-prone skin and reducing redness or scars. Depending on the specific type of extract used (e.g., Centella Asiatica Extract (Madecassoside 90%) or Pure-TECA™), solubility can vary. Some forms are easily water-soluble, while others like TECA are not water or oil soluble and need to be dispersed or dissolved in glycols (like the Propylene Glycol in your formula) with heat. A 5% concentration might be high depending on the solubility of your specific extract type, potentially leading to dispersion issues if not properly handled.
• Green Tea Extract 5%: Green Tea Extract, containing antioxidants like EGCG (Hi-EGCG™ or Pure-EGCG™), offers anti-inflammatory and antioxidant benefits and can help reduce oiliness. It is generally water-soluble. Some forms are sensitive to heat and light and should be added in the final cooling phase of the formulation.
• Copper Peptide (GHK-Cu) 3%: Copper Peptides are known for their skin regeneration and wound-healing properties, potentially helping with acne scars and skin texture. They are water-soluble and should be added in the final step below 40°C to maintain stability. The recommended usage rate for the Copper Peptide (GHK-Cu, 1000ppm Solution) is typically 1-3%, so 3% is at the higher end but within the suggested range for this specific solution type. If using a powder form like Copper Peptide (GHK-Cu Copper Tripeptide-1, 1:1) Powder), the recommended rate is much lower (0.01-1%). Ensure you are using a type suitable for a 3% concentration. Copper Peptides are sensitive to low pH and certain chelating agents like Disodium EDTA (which is not in your list, so that's good). The optimal pH range is typically 4.5-7.4.
• Propylene Glycol 2%: This is a common humectant and solvent that helps dissolve or disperse other ingredients and adds moisture. It is compatible with the other components.
• Zinc PCA 1%: Zinc PCA is excellent for reducing oiliness and has some antibacterial properties, making it suitable for acne-prone skin. It is water-soluble and the 1% concentration is within the typical usage range for oil control. It is most soluble in a pH range of 4-6.

Summary:

The ingredients in your formulation are generally compatible chemically and functionally for a gel-based product targeting concerns like acne, oiliness, and skin repair. The main points to consider are:

1. Niacinamide Concentration: While 10% is possible, especially with high-purity grades, always perform a patch test due to potential irritation.
2. Centella Asiatica Extract Solubility: Ensure the specific type of Centella extract you are using is soluble or dispersible at a 5% concentration in your gel base, potentially utilizing the Propylene Glycol.
3. Copper Peptide Concentration: Confirm the type of Copper Peptide used is suitable for a 3% concentration (e.g., a solution form).
4. Mixing Procedure: Add heat-sensitive ingredients like Copper Peptide and Green Tea Extract in the final cooling phase (below 40°C).
5. pH: Aim for a final pH that is compatible with all ingredients, ideally in the range of 4.5-6.5, which suits most components listed.
6. Patch Testing: Always test the final formulation on a small area of skin before widespread use.