Water-in-Oil Body Milk Formulation: Stickiness, Mixing, and Stability

Question

I am trying to formulate a Water-in-Oil body milk, potentially for oily skin and daytime use. I have several questions about the formulation process and characteristics:

Will a Water-in-Oil formula feel sticky, especially for oily skin and if used during the daytime? How does the stickiness compare to an Oil-in-Water formula?
Do water-soluble ingredients need to be heated to dissolve them?
Can I use bottled mineral water for the water phase? Are there any specific considerations or recommendations?
When using Water Capsule, how long should I stir the mixture to achieve homogeneity for different batch sizes, specifically 100ml and 500ml?
What is the typical expected shelf life for a homemade cosmetic formula like this?

(Note: The staff provided an adjusted formula based on my initial attempt, which includes the following components:)

Water Phase:

Natto Gum 5%
Vitamin B5 3%
Vitamin B3 3%
Rice Vitamin 3%
WhiteCumin™ 3%
Phenoxyethanol SA 1%
Light Cream Maker 1%
น้ำกลั่น (Distilled Water) Remaining percentage

Oil Phase:

LipidSoft Lite 7%
Water Capsule 3%

MySkinRecipes Expert · Accepted Answer

Based on the discussion and the staff's recommendations, here are the answers to your questions:

Regarding your questions about making a Water-in-Oil body milk formula for oily skin:

Stickiness for oily skin/daytime use: Water-in-Oil (W/O) formulas are generally stickier than Oil-in-Water (O/W) formulas, even with a low oil content, due to their structural nature. The formula adjusted by the staff using Water Capsule and LipidSoft Lite is designed to be as light as possible for a W/O formula, but it may still feel stickier than typical O/W lotions, especially if used on the face (based on jiralexk's experience which noted more stickiness on facial skin). However, it might feel more comfortable on the body. Suitability for daytime use depends on your personal preference.
Heating water-soluble ingredients: Most water-soluble ingredients can be dissolved in water without needing high temperatures. You can dissolve them in room temperature water.
Using bottled mineral water: Bottled drinking water can be used. However, it is recommended to add 0.2% Disodium EDTA to help chelate ions in the water, and you should avoid brands with high suspended solids.
Stirring time: For Water Capsule, stirring until homogeneous (no separated oil phase) for a 100ml batch might take about 1-4 minutes. For a 500ml batch, it might take longer until the mixture is completely homogeneous and no oil phase is separated.
Shelf life: If the formula uses an appropriate amount of preservative and is produced in a clean environment and stored in suitable packaging, homemade cosmetics generally have a shelf life of approximately 1-2 years. However, determining the exact shelf life requires stability testing.

The staff has adjusted the formula you proposed to be more suitable, as mentioned in the previous post.