Review of DIY Skin Brightening Lotion Formula with High Shea Butter

Your inquired lotion formula for skin whitening is considered a good formula. It contains key ingredients that help brighten the skin and provide moisture.

Based on the formula and steps you provided, as well as the additional feedback:

• Ingredients: Using Vitamin B3 (Niacinamide) together with NAG (N-Acetyl Glucosamine) at a 4% concentration each is an excellent combination for helping with skin brightening, reducing dark spots, and also strengthening the skin barrier. Allantoin helps soothe the skin and reduce irritation. Glycerin is a good humectant for moisture.
• Shea Butter 20%: As cosmeceutical7 commented, 20% Shea Butter is quite high for a general body lotion. It might feel heavy and greasy, especially in humid climates or if you don't have very dry skin. Reducing the amount of Shea Butter, for example, starting at 5%, and perhaps adding other moisturizers that provide a lighter feel would make the lotion more pleasant to use. Interesting moisturizers such as MOIST72 or WaterLock, as mentioned, are good options to enhance moisture without making the texture heavy.
• Manufacturing Steps: The steps you described are all correct.
  1. Mixing the water phase (Water, Glycerin, Vitamin B3, NAG, Allantoin) first is the correct method for water-soluble ingredients.
  2. Warming the Shea Butter in the oil phase to melt at 70-80 degrees Celsius is also correct, as Shea Butter is a fat that needs to be melted for mixing.
  3. Mixing the melted Shea Butter with Sepipus400 (which is likely Sepinov EMT10) is a step in preparing the oil phase and emulsifier/thickener, which is correct according to emulsification principles.
  4. Combining all mixtures to form the emulsion and adding the preservative at the end is also a standard and correct procedure.
• Allantoin 0.5% of Water: Generally, ingredient percentages are calculated based on the total weight of the formula (Total Formula Weight). If you intend to use 0.5% Allantoin of the total formula, that is achievable. Allantoin can dissolve in water up to about 0.5% at room temperature and dissolves better with the help of Glycerin.

Conclusion:

The formula you have devised contains good ingredients and is effective in helping to brighten the skin and provide moisture, especially through the synergistic action of Vitamin B3 and NAG. The manufacturing steps are correct. However, the main consideration is that 20% Shea Butter might result in a texture that is too heavy for some people. Adjusting the amount of Shea Butter and supplementing with other moisturizers will help achieve a better texture while maintaining the skin-nourishing benefits.