Formulation Advice for Your Serum Blend

Mixing Pitera, Repair Activator, Marine Plankton, and 4MSK is possible as they are generally water-soluble ingredients. However, combining them at the percentages you've listed (totaling 100%) without other formulation components is generally not recommended for several reasons:

• Stability: A simple mixture of concentrated actives may not be stable over time and could separate or degrade.
• Preservation: While some of these ingredients may contain preservatives in their raw material form, mixing them at high percentages can dilute the preservative system below effective levels, leading to microbial growth. A broad-spectrum preservative is crucial for water-based formulations.
• Efficacy and Irritation: Using such high concentrations of multiple actives might increase the risk of skin irritation without necessarily providing significantly enhanced benefits compared to using them at their recommended rates within a well-formulated base.
• Texture: The resulting mixture will likely be very watery and may not have a pleasant texture for application.

Additionally, the percentage of Marine Plankton you proposed (2.5%) is slightly above the typical recommended usage rate (1-2%).

Recommendations:

To create a stable, safe, and effective serum, consider incorporating these actives into a complete formulation base. A standard serum formulation typically includes:

1. Water: As the primary solvent.
2. Thickener: To achieve a desirable serum consistency.
3. Preservative System: A broad-spectrum preservative is essential to prevent bacterial and fungal contamination.
4. pH Adjuster: To ensure the final product pH is suitable for skin and ingredient stability (typically between 4.5 and 6.0 for many actives).
5. Humectants (Optional but Recommended): Ingredients like Hyaluronic Acid or Panthenol can enhance hydration.

You would typically use lower percentages of the active ingredients (within their recommended ranges) and make up the rest of the formula with the base components.

For example, a more stable approach would be to create a serum base (Water, Thickener, Preservative, pH Adjuster, Humectant) and then add your desired actives at appropriate usage rates:

• Pitera (Galactomyces Ferment Filtrate): Use within the 1-100% range, but consider a lower percentage like 10-20% in a full formula.
• Repair Activator (Bifida Ferment Lysate): Use within the 5-100% range, perhaps 5-10% in a full formula.
• Marine Plankton: Use within the 1-2% range.
• 4MSK (Potassium Methoxysalicylate): Use within the 1-3% range.

By formulating this way, you ensure the product is stable, safe from microbial contamination, has a good texture, and the actives are delivered effectively without excessive irritation risk.