Review of a Strong Skin Whitening Gel Formula

Hello! I can help review your formula for a strong skin whitening gel that you want to be fast-absorbing, comfortable, and non-sticky.

Based on the ingredients you listed:

• Water
• Disodium EDTA (2NA EDTA)
• Propylene Glycol
• Glycerin
• AnyGel (Dehydroxanthan Gum) - Gelling agent
• Lactic Acid (90% AHA) - Exfoliant, brightener
• Salicylic Acid - Exfoliant, can aid penetration
• Niacinamide (Safe-B3) - Brightener, skin conditioner
• Phenoxyethanol - Preservative
• Fragrance

Analysis of your formula:

1. "Strong" Whitening Effect: Your formula uses Lactic Acid (at ~4.5% active) and Salicylic Acid (2%), which are potent exfoliants that help improve skin tone and reduce hyperpigmentation. The concentration of these acids is high, aligning with your goal for a "strong" effect. Niacinamide (3%) also contributes to brightening. This combination is powerful for addressing uneven skin tone and dark spots.

   • Important Note: High concentrations of AHAs and Salicylic Acid can cause significant irritation, redness, peeling, and increased sensitivity to the sun. This formula has a high potential for these side effects.

2. Texture (Fast Absorption, Comfortable, Stickiness):

   • AnyGel (Dehydroxanthan Gum) at 1% will create a gel texture. Dehydroxanthan Gum is often chosen for a less sticky feel than some other gums, but 1% is a relatively high concentration for a very light, fast-absorbing gel. It might feel slightly viscous or even a bit "ropy" depending on the specific grade and how it's hydrated.
   • Propylene Glycol (2%) and Glycerin (2.5%) are humectants that help hydrate the skin but can sometimes contribute to a slightly tacky feel, especially in humid conditions.
   • The high water content helps with absorption.
   • Whether the final product feels sticky and absorbs quickly will depend on the exact rheology created by the AnyGel at this concentration in this specific formula. It might be moderately viscous and could have some tackiness.

Points for Consideration and Potential Adjustment:

1. Total Percentage: The percentages you listed add up to 103%. Please double-check your percentages to ensure they total 100%.
2. pH Adjustment is CRUCIAL: For Lactic Acid and Salicylic Acid to be effective exfoliants and for the formula to be safe, the pH must be adjusted to a low range (typically between 3.0 and 4.0). A pH between 3.5 and 4.0 is often targeted to balance efficacy and reduce irritation compared to lower pH values. You absolutely need a pH meter to make this formula. Without proper pH adjustment, the acids may not work effectively, or worse, they could cause severe irritation.
3. High Irritation Risk: Given the high concentration of acids, this formula is likely to be irritating, especially if you are new to using high-strength exfoliants. Start by using it infrequently (e.g., 2-3 times per week) and gradually increase frequency if your skin tolerates it. Always perform a patch test on a small area before applying it to larger areas. Strict daily sun protection is essential when using products with AHAs/BHAs.
4. Texture Adjustment: If the resulting gel is too sticky or heavy for your preference, you could try slightly reducing the AnyGel concentration (e.g., to 0.7% or 0.8%) and observe the texture and stability. Be careful not to reduce it too much, as it might affect the stability of the formula.
5. Adding Soothing/Hydrating Ingredients: To improve the "comfortable feel" and help counteract potential irritation and dryness from the acids, you might consider adding soothing ingredients like Allantoin, Bisabolol, or Panthenol, or additional hydrating ingredients like Sodium Hyaluronate.

In summary: Your formula contains powerful ingredients for skin brightening ("เน้นแรง"). However, it carries a high risk of irritation. Proper pH adjustment is absolutely essential for both efficacy and safety. You may also need to fine-tune the gelling agent concentration to achieve your desired texture regarding stickiness and absorption.