Formula Adjustments and Ingredient Functionality

1. Adjusting the BHA Formula and Adding Ingredients: Adding Vitamin B3 (Niacinamide) to your BHA formula is generally beneficial and does not make the formula worse. Vitamin B3 offers multiple skin benefits, including reducing inflammation, improving hyperpigmentation, strengthening the skin barrier, and controlling oiliness, which are all helpful for acne-prone skin. While the original store formula might have omitted it for simplicity or to avoid potential pH issues with other ingredients, Vitamin B3 works well at a pH of around 4, which is where your current formula is.
2. Maintaining BHA pH: Keeping the pH lower (e.g., 3.5) primarily boosts BHA's exfoliation power. However, for dissolving clogged pores, a pH of around 4 is still quite effective. Since your main goal for this formula is clog dissolution, pH 4 remains suitable. The original formula likely didn't recommend a lower pH to prioritize clog dissolving and potentially reduce irritation, as very low pH is more critical for strong exfoliation. Your current pH of 4 is appropriate for your stated goal.

Adding Silicones to Formulas

3. Impact of Silicone Gel + Cyclomethicone in Vitamin C Formula: Adding Silicone Gel and Cyclomethicone to improve the texture and feel of your Vitamin C formula does not negatively affect the efficacy of active ingredients like L-Ascorbic Acid or Glutathione. They act as texture enhancers and carriers. The primary concern with L-Ascorbic Acid is its stability over time, which can degrade and yellow, especially with exposure to light, air, or heat. The fact that your formula hasn't yellowed is a good sign of its current stability.
4. Suitability of Adding Silicones to AHA Formula: You can consider adding Silicone Gel and Cyclomethicone to your AHA formula to improve its texture. However, as the Staff mentioned, combining a high water content with high silicone content and using Light Cream Maker can be challenging. Light Cream Maker is primarily for Oil-in-Water emulsions and may not be ideal for formulas with a large silicone phase. For a smooth, dry feel typical of Water-in-Silicone emulsions, you might need to use an emulsifier like Warp Cream Maker, which is designed for this system, or adjust the water/silicone ratio significantly if using Light Cream Maker. Testing in a small batch is highly recommended.

Enhancing Whitening Efficacy

5. Whitening Results and Timeframe: Two months of using your Vitamin C and AHA formulas might be a bit short for dramatic whitening results, especially on the arms. Skin cell turnover takes time (around 28 days), and consistent action on melanin production is needed. More noticeable results often appear after several skin cycles. The combination of Vitamin B3 and N-Acetyl Glucosamine (NAG) is effective for brightening and reducing dark spots, with results typically becoming visible within one to two skin cycles (1-2 months), but more significant changes may take longer.

Additional Recommendations and Using Existing Ingredients

6. Based on the ingredients you have and those discussed, you have several potent actives that can be combined for various skin goals:
   • BHA Formula (for acne and oil control): Your current formula is a solid base. Adding NAG to this BHA formula (at around pH 4) is a good approach to add brightening benefits.
   • Whitening/Spot Reduction Formulas: You can continue using your Vitamin C (L-Ascorbic Acid) + Glutathione formula and your AHA (Lactic Acid) + Vitamin B3 + NAG formula. This combination helps with exfoliation, reducing marks, and overall brightening.
   • Boosting Whitening: To enhance whitening further, consider adding Alpha Arbutin to your B3 + NAG formula, as they work well together. Other highly effective options include ChromaWhite™ (oil-soluble) and AEPWhite™ (water-soluble).
   • Additional Oil Control: If needed, consider creating a separate formula with ingredients like Pure MSM™ or Zinc PCA, which are effective for oil control, or Licorice Extract for anti-inflammatory and oil control benefits. (Be mindful of pH compatibility if combining with other actives).
   • Formulation Tips: Always check ingredient compatibility and optimal pH ranges. Formulating with high silicones and water using Light Cream Maker can be tricky; consider Warp Cream Maker or adjusting ratios, and always test in small batches. Vitamin C (L-Ascorbic Acid) should not be mixed with Pure MSM™ in the same formula. Glutathione can help stabilize L-Ascorbic Acid at a 1:10 ratio.