Underarm Care Formulation Advice

Addressing underarm darkness and bumpy skin ("chicken skin") involves using suitable active ingredients in a base that feels comfortable and dries quickly.

Key Active Ingredients

For darkness, effective ingredients include:

• Vitamin B3 (Niacinamide): Helps reduce hyperpigmentation and strengthens the skin barrier.
• Tranexamic Acid: Known for its ability to reduce melanin production and address dark spots.
• Alpha Arbutin: A popular and effective skin brightening agent.
• N-acetyl-d glucosamine: Works well with Niacinamide to improve skin tone and can also help with exfoliation.

For bumpy skin (often related to clogged pores or irritation), gentle exfoliation is key. Salicylic Acid (BHA) is effective for this, helping to dissolve pore blockages and promote skin cell turnover.

Choosing the Right Base

The challenge for underarm products is creating a formula that dries quickly and isn't sticky. Silicone-based formulas are often preferred for this reason, providing a light, smooth feel.

Silicone-Based Serum/Gel

You experienced separation when trying to make a silicone base with Cyclomethicone, SiliSolve, and water. The key to success with this type of formula is the mixing order and ingredient ratios.

• Correct Mixing Method: Always mix the water-soluble ingredients (like Vitamin B3, N-acetyl-d glucosamine, Tranexamic Acid) into the water first (Phase A). Mix the silicone oil (Cyclomethicone) and the emulsifier (SiliSolve) together (Phase B). Then, slowly add Phase A (water phase) into Phase B (silicone phase) while stirring continuously. Adding the silicone phase to the water phase will make it much harder to emulsify.

• Achieving a Thicker Texture: A simple Cyclomethicone/SiliSolve/Water mix can be very liquid. To get a thicker, more gel-like consistency while keeping the quick-drying feel, you can:

  • Increase the percentage of water relative to the Cyclomethicone.
  • Replace some of the Cyclomethicone with Silicone Gel.

  A suggested starting point for a thicker texture is:

  • Cyclomethicone 10%
  • Silicone Gel 10%
  • SiliSolve 1%
  • Water 79%

  Mix the Cyclomethicone, Silicone Gel, and SiliSolve. Then, slowly add the water (containing dissolved actives) while mixing.

Cream Base (Light Cream Maker)

Using a cream maker like Light Cream Maker™ is suitable for creating a cream texture. However, as discussed, a traditional cream might not provide the desired quick-drying, non-sticky feel that is often preferred for underarm products compared to a volatile silicone base.

Using BHA (Salicylic Acid)

A 2% Salicylic Acid toner can be too strong and irritating for the sensitive underarm skin if applied broadly. It is recommended to use Salicylic Acid as a gel (e.g., using a gel maker like Pro Polymer) and apply it only as a spot treatment on the bumpy areas ("หนังไก่") rather than the entire underarm.

Application Order

If you are using a BHA gel for spot treatment and a separate whitening serum (silicone-based or otherwise), do not apply them immediately one after the other. Apply the BHA gel first to the bumpy areas, wait for a few minutes for it to absorb and work, and then apply the whitening serum to the entire underarm area. This helps ensure the BHA works effectively at its optimal pH before applying another product that might change the pH.