Retinal Cream Formulation, Mixing, and Stability (Yellowing)

Hello! I can help review your proposed formula and mixing steps.

Regarding Retinal vs Retinol: As the staff explained, Retinal (Retinaldehyde) is a more potent form of Vitamin A than Retinol (Retinol Palmitate). This means you need a lower concentration of Retinal to achieve similar results, and using higher concentrations can increase the risk of irritation.

Your proposed formula includes several changes from your original one (increased Retinal, removed Shea Butter, added BioSulphur, Soy Extract, WhiteCumin, Resveratrol, and Disodium EDTA). The total percentage of non-water ingredients is significantly higher (around 40.5%). This is a complex formula and might affect the texture and stability compared to your previous one.

The yellowing you experienced in the previous batch is likely due to the oxidation of Retinal. Proper packaging (airless, opaque container) and storage (cool, dark place) are crucial for maintaining its stability and preventing discoloration. Vitamin E Acetate helps, but packaging and storage are key.

Let's look at your proposed mixing steps:

• You listed several ingredients for the water phase (Water, EDTA, Vitamin E, Preservative, Satin Cream Maker, BioSulphur, WhiteCumin, Soy Extract, Resveratrol). Some of these are not typically added to the water phase and heated: Vitamin E Acetate is oil-soluble and should be in the oil phase. BioSulphur, WhiteCumin, Soy Extract, and Active Resveratrol are solids or extracts that often need specific dispersion/dissolution methods and are best added in the cool-down phase to protect their efficacy and stability, especially Soy Extract and Resveratrol which the website mentions adding at the "final step". Satin Cream Maker's placement depends on its type, but often goes in the oil phase for creams.
• Your oil phase ingredients (Retinal, FloraSolve, LipidSoft Dry) are correctly grouped as oil-soluble/miscible. However, heating Retinal to 60C is not recommended as it is heat-sensitive. Retinal should ideally be added in the cool-down phase below 30-40C.
• Combining phases at temperature is standard.
• The instruction from the website to add Soy Extract and Active Resveratrol™ at the "final step" means adding them after the main emulsion has been formed and cooled down, not in the initial water phase.

Creating a stable emulsion with this many ingredients, especially solids and sensitive extracts, requires careful consideration of solubility, dispersion, and addition temperature. A general mixing approach would involve:

• Phase A (Water Phase): Water, water-soluble ingredients (like EDTA, some preservatives). Heat.
• Phase B (Oil Phase): Oils, emulsifiers (like Satin Cream Maker, LipidSoft Dry, FloraSolve can act as a solvent), oil-soluble ingredients (like Vitamin E Acetate). Heat.
• Combine Phase B into Phase A while stirring/homogenizing at temperature until emulsified.
• Cool down the emulsion.
• Cool-down Phase: Add heat-sensitive ingredients (like Retinal), ingredients needing dispersion (like BioSulphur, WhiteCumin), and ingredients needing specific dissolution/added at the end (like Soy Extract, Active Resveratrol™ dissolved in a suitable solvent like glycol). Stir well until uniformly dispersed/dissolved.

The staff previously suggested a simpler modification: adding Soy Extract (5%), WhiteCumin (3%), and Active Resveratrol (5%) and reducing LipidSoft Dry to 2%, keeping other ingredients from your original formula (including Shea Butter). This might be easier to formulate and maintain stability.

If you proceed with your proposed formula including BioSulphur and EDTA, please be aware that it's a complex blend, and careful mixing and stability testing will be important.