Adding Whitening Actives to Lotion: Solubility, Stability, and Efficacy

Adding active ingredients like Niacinamide, NAC, and Tranexamic Acid directly into a finished lotion product like the Vaseline lotions you mentioned is generally not recommended for several reasons:

• Solubility and Dispersion: These ingredients are typically powders that need to be properly dissolved and dispersed in a suitable base during the manufacturing process. Simply stirring them into a finished lotion in the bottle will likely result in uneven distribution, clumping, and the ingredients not fully dissolving. This means you won't get a consistent concentration throughout the product, and the ingredients may not be able to effectively penetrate the skin.
• Stability: The stability of active ingredients is highly dependent on the overall formulation, including pH, temperature, and the presence of other ingredients. Adding external ingredients can disrupt the carefully balanced chemistry of the original lotion, potentially causing the active ingredients to degrade quickly and lose their effectiveness. The product information for Pure-NAC™ (N-acetylcarnosine), for example, suggests avoiding heat above 40°C and storing it in the refrigerator for stability. Mixing it into a lotion stored at room temperature could affect its longevity.
• Concentration: The concentration of NAC you proposed (4%) is significantly higher than the typical recommended usage rate for Pure-NAC™ (N-acetylcarnosine), which is 0.2-1.0%. Using a much higher concentration could lead to solubility issues, stability problems, and potentially skin irritation.
• Preservation System: Adding new ingredients can introduce microbes and may overwhelm or dilute the existing preservative system in the lotion, leading to bacterial or fungal contamination over time.
• Texture and Feel: Incorporating powders can drastically change the texture, consistency, and feel of the lotion, making it gritty or unpleasant to use.
• Efficacy and Safety: The effectiveness and safety of a cosmetic product depend on the precise interaction of all ingredients. Adding high concentrations of actives without proper formulation knowledge and testing can reduce efficacy or even cause adverse skin reactions.

This applies to both the Vaseline Healthy White Fresh & Fair Cooling lotion and the Vaseline Gluta Hya Serum Burst Lotion Dewy Radiance. Their formulations are designed to be stable and effective as they are, and adding external ingredients can compromise this.

A better approach to achieve enhanced whitening is to use products that are already professionally formulated with these active ingredients at appropriate concentrations and in stable bases. Alternatively, if you are interested in creating custom formulations, it is best to start with cosmetic bases designed for adding active ingredients or to follow tested and validated formulation recipes.

Therefore, I do not recommend attempting to mix Niacinamide 5%, NAC 4%, and Tranexamic Acid 3% into your Vaseline lotions by simply stirring them in the bottle.