Formula Assessment

The structure of your formula is a standard oil-in-water (O/W) emulsion, which is suitable for a lotion texture. Let's look at the components:

• Oil Phase: Contains oil (2%), Emulsifying Wax (4%), Stearic Acid (4%), and IPM (3%).

  • Emulsifying Wax and Stearic Acid are key for forming the emulsion and providing thickness. 4% of each should help create a stable and reasonably thick lotion.
  • IPM (Isopropyl Myristate) is a light emollient that aids spreadability and helps reduce greasiness, contributing to a fast-absorbing feel.
  • The total oil phase (including emulsifiers and IPM) is around 13%.

• Water Phase: Contains Distilled Water (70%). This is the continuous phase of the emulsion.

• Sunscreen Phase: Contains Silicone (5%) and Titanium Dioxide (3%).

  • Silicone (like Silicone Gel 9040) is excellent for improving skin feel, making the lotion smooth, non-greasy, and helping it absorb quickly. It can also provide a matte finish.
  • Titanium Dioxide is a physical UV filter. At 3%, it will offer some level of UV protection.

• Final Phase: Contains Preservative and Fragrance. These are necessary additions for product safety and sensory appeal.

Can this formula achieve your goals?

• Thick lotion, doesn't spill when inverted: Yes, with 4% Emulsifying Wax and 4% Stearic Acid, you should be able to achieve a lotion consistency that is thick enough not to spill easily.
• Fast absorbing, not greasy: Yes, the inclusion of IPM and Silicone will significantly help with this, providing a light, smooth, and non-greasy feel.
• BB sunscreen without white cast: This is the most challenging part with this formula as written.
  • A "BB" effect typically implies some level of skin tone coverage or evening out.
  • Achieving this without a white cast using only 3% Titanium Dioxide depends heavily on the type of Titanium Dioxide used.
  • If you use a standard pigment-grade Titanium Dioxide (like Titanium Dioxide 250nm Pigment), 3% might provide some coverage but is very likely to leave a noticeable white cast, especially on darker skin tones.
  • If you use a transparent or nano-sized Titanium Dioxide (like Titanium Dioxide Transparent 15nm), it will provide UV protection with minimal to no white cast, but it will offer very little coverage for a "BB" effect.
  • To get both coverage and minimal white cast from physical filters, formulators often use higher concentrations of specially coated, small particle size Titanium Dioxide and Zinc Oxide, or incorporate skin-toned pigments (like iron oxides) to counteract the white cast.

Recommendation:

The formula is a good starting point for a thick, non-greasy lotion sunscreen. However, to achieve a true "BB" effect with coverage and no white cast, you will likely need to:

1. Specify and potentially increase the percentage of a high-quality, coated, small-particle Titanium Dioxide designed for transparency or minimal white cast.
2. Consider adding Zinc Oxide, which also provides broad-spectrum UV protection and can help with coverage, depending on the type.
3. If significant coverage is desired, you might need to incorporate skin-toned pigments (iron oxides) into the formula to match skin color and counteract any potential white cast from the physical filters.

Without knowing the specific "น้ำมัน" (oil) used, its properties could also slightly affect the final texture and feel.

In summary, the formula is suitable for the desired texture and feel, but the BB/no white cast requirement at 3% Titanium Dioxide is difficult to achieve without selecting a very specific type of Titanium Dioxide or modifying the formula further.