Caprylyl Glycol Solubility

While Caprylyl Glycol is listed as soluble in water, its maximum solubility in water is approximately 1.8% at 25 degrees Celsius.

When you try to dissolve 5% Caprylyl Glycol in water at room temperature, you are exceeding its solubility limit. The amount above 1.8% will not fully dissolve and will remain dispersed or suspended in the water, appearing as droplets or a separate phase, similar to how oil behaves in water when not emulsified or solubilized. This is why you observe the solution not being clear and homogeneous at a 5% concentration.

How to Address This

1. Use within the solubility limit: If you need a clear, homogeneous solution in pure water, use Caprylyl Glycol at a concentration of 1.8% or less.
2. Use a solubilizer: If you need to use Caprylyl Glycol at a higher concentration (like 5%) in a water-based formula, you will need to incorporate a solubilizer. Solubilizers are ingredients (often surfactants) that help disperse and stabilize substances that are not fully water-soluble, allowing them to remain evenly distributed in the water phase.
3. Incorporate into an emulsion: If your formula is an emulsion (like a cream or lotion with both oil and water phases), Caprylyl Glycol can often be incorporated into either the water or oil phase, or at the interface, depending on the specific formulation and other ingredients.

The appearance you described and showed in the image is consistent with trying to dissolve a substance above its maximum solubility in a solvent.