Serum Formulation Issues: Skin Irritation and Watery Texture

Question

I have created a formula approximately as follows and tested it, resulting in stinging and itching skin. It stings more on areas with wounds than on intact skin. After using it for a while, the skin where it was applied started peeling/pilling.

I would like to ask which ingredient quantity I should reduce or which ingredient I should remove?
I intended the skin feel to be more like a serum with more body (the formula turned out watery as I designed it).

Could the team please provide recommendations?

Formula:

Aqua (Water) 57%
Glycerin 6%
Propylene Glycol 3%
GlucoBright™ (Acetyl glucosamine) 4%
Double Hyaluron Liquid 10%
Safe-B3™ (Vitamin B3, Niacinamide, Switzerland) 4%
Acetyl Hexapeptide-8 (eq. Argireline) 5%
Z-White™ 0.9%
Yeast Radiance™ 3%
Zinc PCA 1%
Pal-GHK, Pal-GQPR (eq. Matrixyl 3000) 5%
Mild Preserved Eco 1%

MySkinRecipes Expert · Accepted Answer

Hello, regarding the formula you provided and the symptoms you experienced (stinging, itching, peeling) and the watery texture, the team would like to offer the following advice:

Regarding stinging, itching, and peeling:
These symptoms may be caused by irritation from certain ingredients in the formula, especially Niacinamide (Safe-B3™) at a concentration of 4%, which might be too high for some skin types or when applied to existing open wounds. Using multiple active ingredients together at relatively high concentrations can also cause skin irritation and weaken the skin barrier.

Recommendations for irritation:

Try reducing the amount of Safe-B3™ (Niacinamide) first. You might reduce it to 2% or even 1% to see if the symptoms improve. Niacinamide is a good ingredient, but sometimes high concentrations can cause irritation.
Avoid applying the serum directly to areas with open wounds, as this will easily cause stinging and irritation.
If reducing Niacinamide doesn't help, you might consider reducing other ingredients that could potentially cause irritation, such as the Zinc group (Z-White™, Zinc PCA) or Acetyl Glucosamine, but try reducing Niacinamide first.

Regarding the watery texture:
This formula consists mostly of water and highly water-soluble ingredients, but it lacks ingredients that help increase viscosity or create a gel texture. This results in a watery consistency.

Recommendations for texture:

If you want the texture to be thicker like a serum, you should add a gelling agent or thickener to the formula.
There are many types of gelling agents that can be used in water-based formulas, such as Hyaluronic Acid powder (different from the Double Hyaluron Liquid you are using), which can significantly increase viscosity with just a small amount, Carbomer, Xanthan Gum, or Cellulose Derivatives.
Adding a gelling agent will require reducing the amount of water (Aqua) proportionally. You should also check the recommended usage rate for each type of gelling agent to achieve the desired viscosity.

Additional recommendation:
After adjusting the formula, you should test it on a small area first to check for allergic reactions or irritation again.