Formula Review

Overall, your formulations contain many beneficial active ingredients. Below is a review of each formula with considerations for compatibility and suitability.

1. Eyebrow Serum

This formula includes ingredients aimed at stimulating eyebrow growth and improving the skin around the brows.

• Compatibility: The ingredients appear generally compatible. The pH of the final formula should be adjusted to be within the 3.5-5.5 range for optimal stability of Long-Lash™. Ensure proper mixing procedures, especially adding heat-sensitive ingredients like Long-Lash™ and Biotinyl-GHK in the final step below 40°C.
• Suitability: The combination of Long-Lash™, Energy-Blend, and Biotinyl-GHK is well-suited for promoting hair growth. Safe-B3 and Licorice Extract can help soothe the skin. Dimethyl Isosorbide will enhance penetration of the actives. However, Energy-Blend at 5% might cause a warming or hot sensation, particularly in the sensitive eyebrow area. You may consider reducing its concentration if this is a concern.

2. Toner

This toner formula focuses on hydration and soothing the skin.

• Compatibility: The ingredients are generally compatible and suitable for a water-based toner. The pH of the final formula should ideally be in the 4-7 range for the stability of Panthenol. When mixing, avoid prolonged or vigorous stirring/shaking after adding Natural Moisturizing Amino Acids to prevent potential issues.
• Suitability: Natural Moisturizing Amino Acids, Glycerin, Mannitol, and Panthenol are excellent humectants and soothing agents, making this formula highly suitable for hydrating and calming the skin. Mild Preserved Eco provides effective preservation for a water-based product.

3. Night Serum I

This serum is designed for anti-aging, repair, and brightening.

• Compatibility: The active ingredients have overlapping pH ranges (mostly between 4 and 7), suggesting good compatibility if the final formula pH is adjusted accordingly. Ingredients like Galactomyces Ferment Filtrate, Repair Activator, Ume Extract, and GlucoBright should be added in the final phase, avoiding high temperatures (below 40°C for ferments and Ume Extract). Dimethyl Isosorbide will help solubilize and penetrate the water-soluble actives. Satin Cream Maker can effectively thicken this water-based serum.
• Suitability: This is a potent serum with a high concentration of actives targeting multiple concerns: Galactomyces Ferment Filtrate and Repair Activator for skin health and repair, Safe-B3 and GlucoBright for brightening and texture, Willow Bark Extract for exfoliation and soothing, Ume Extract for anti-glycation, and Japanese Cedar for barrier support and cell turnover. The high concentration of Galactomyces Ferment Filtrate (50%) might result in a slightly greasy feel for some users.

4. Night Serum II

This serum focuses on wrinkle reduction and skin tightening.

• Compatibility: The peptides (Acetyl Hexapeptide-8, Matrixyl 3000, Copper Peptide) and DMAE should be added in the final phase below 40°C to maintain their efficacy. Copper Peptide requires a pH between 4.5-7.4 and should not be combined with chelating agents, which are not present in this formula. The pH ranges of the other actives (Panthenol, Rhamnose, MOIST72, Mild Preserved Eco, Satin Cream Maker) are generally compatible within the 4-8 range. The final formula pH should be adjusted to be within 4.5-7.4 for Copper Peptide stability. Dimethyl Isosorbide will enhance penetration. Satin Cream Maker and Hydro Gel contribute to the serum's texture.
• Suitability: This formula combines powerful anti-aging peptides (Acetyl Hexapeptide-8, Matrixyl 3000, Copper Peptide) with skin-tightening DMAE. Panthenol, Rhamnose, MOIST72, and Hydro Gel provide hydration and soothing benefits. The 5% concentration of DMAE is at the higher end of typical recommendations and may cause irritation or a sticky feeling for some individuals. Consider starting with a lower concentration of DMAE if targeting users with sensitive skin.

5. Night Oil

This formula is intended as an anti-aging night oil.

• Compatibility: Squalane, Perfect-C, Bakuchiol, and Vitamin E are all oil-soluble and compatible with an oil base. However, Silybum Marianum Extract is listed as a water-soluble powder. Including a water-soluble ingredient at 1% in an anhydrous oil formula will likely result in it not dissolving or dispersing properly, leading to a cloudy appearance and potentially reduced efficacy and stability. It is recommended to either omit the Silybum Marianum Extract or find an oil-soluble form if available. Bakuchiol is recommended to be used with Dimethyl Isosorbide for maximum penetration, which is not included in this formula, although it is oil-soluble and should still provide benefits.
• Suitability: Squalane provides a nourishing oil base. Perfect-C and Bakuchiol are excellent actives for anti-aging and brightening in an oil format. Vitamin E adds antioxidant protection. The primary issue is the inclusion of the water-soluble Silybum Marianum Extract in an oil formula, which is not suitable.

In summary, most of your formulas are well-constructed with compatible and suitable ingredients for their intended purposes, with careful attention needed to pH adjustment and mixing procedures for optimal stability and efficacy of the active ingredients. The Night Oil formula has a significant compatibility issue with the inclusion of a water-soluble extract in an oil base.