Advice for Shimmering Body Oil Formulation

Hello! You're planning to make a Shimmering Body Oil using several ingredients including Fractionated Coconut Oil, Avocado Oil, Sweet Almond Oil, Safflower Seed Oil, Silica Dimethyl Silylate, Tocopheryl Acetate, Isohexadecane, Mica, Iron Oxide, and Titanium Dioxide. Here's some advice based on your questions and the staff's replies:

1. Tocopheryl Acetate (Vitamin E) for preservation: Tocopheryl Acetate primarily functions as an antioxidant in oil-based formulas, helping to prevent the oils from oxidizing and going rancid. It does not act as a preservative against microbial growth, which is generally not an issue in anhydrous (water-free) oil products. For antioxidant purposes, the staff recommended a usage rate of 0.05-0.1%. While some natural oils contain Vitamin E, adding Tocopheryl Acetate provides additional protection to extend the shelf life of your oil blend.

2. Iron Oxide and Titanium Dioxide for color: As the staff mentioned, Iron Oxides and Titanium Dioxide are pigments that will make your body oil opaque. If your goal is a translucent shimmering oil where you see the shimmer particles suspended in a clear or lightly tinted base, these pigments are not suitable. The shimmer effect comes from Mica. If you need to add color while maintaining translucency, you would typically use oil-soluble dyes or pigments specifically designed for transparent oil formulations.

3. Silica Dimethyl Silylate for suspending Mica/pigments: Yes, Silica Dimethyl Silylate can help suspend Mica and other powders by increasing the viscosity of the oil base. However, to effectively prevent settling over time, you will likely need to use a significant amount to create a gel-like structure. The staff suggested starting your testing at 3% to see if it provides sufficient suspension. Suspending solid particles like Mica evenly in oil can be challenging, and you may need to experiment with the concentration of Silica Dimethyl Silylate or explore other suspending agents specifically designed for oil systems if settling is a major concern.

4. Isohexadecane for non-greasiness: Isohexadecane is not strictly necessary to reduce greasiness. If your final oil blend feels too heavy or greasy, a common approach is to adjust the ratio of your base oils. Increasing the proportion of lighter oils like Fractionated Coconut Oil relative to heavier oils such as Avocado Oil or Sweet Almond Oil can help improve the skin feel and reduce greasiness, as suggested by the staff. Regarding the difference between Isohexadecane and Isododecane, Isododecane is a volatile emollient, meaning it evaporates from the skin, leaving a very light, dry feel. Isohexadecane is a non-volatile emollient; it stays on the skin longer. While Isododecane is generally perceived as lighter due to its volatility, the staff noted that the difference in skin feel between the two might not be very significant depending on the overall formulation.

Regarding the issue of shimmer clumping/settling mentioned later in the thread: Mica is a solid powder and will naturally settle at the bottom of a low-viscosity oil over time. To minimize or prevent this, you need to increase the viscosity of the oil base sufficiently to keep the Mica particles suspended. As discussed in point 3, using a suspending agent like Silica Dimethyl Silylate at an effective concentration is key. You may need to experiment to find the right balance between texture and suspension stability.

As you are new to formulating, testing small batches and observing the stability (especially the suspension of Mica) over time is highly recommended. Good luck with your Shimmering Body Oil!