Feedback on your Serum Formulation

Hello! Thank you for reaching out regarding your serum formulation for oily, acne-prone skin with hyperpigmentation and for brightening. The ingredients you've chosen (NAG, Niacinamide, Panthenol, Zinc PCA) are excellent choices for these concerns.

Let's review your proposed formula based on a total batch size of 1000g (assuming "น้ำ 1,000 กรัม" was meant to indicate the total batch size, with water being the remaining amount):

• NAG (2%): 2% of 1000g is 20g. Your calculation is correct. NAG is great for hyperpigmentation and works well with Niacinamide.
• B3 (Niacinamide) (4%): 4% of 1000g is 40g. Your calculation is correct. Niacinamide is a fantastic multi-tasker for oily skin, acne, barrier function, and dark spots.
• B5 (Panthenol) (5%): 5% of 1000g is 50g. Your calculation is correct. Panthenol is soothing and hydrating, good for irritated skin. 5% is a bit high for a serum and might feel slightly sticky, but it's not necessarily wrong.
• Zinc PCA (1%): 1% of 1000g is 10g. Your calculation is correct. Zinc PCA is excellent for controlling oil and helping with acne.
• DMAE (4%): 4% of 1000g is 40g. Your calculation of 10.10g is incorrect for a 1000g batch at 4%. DMAE is typically used for skin firming and is less commonly included in formulations primarily targeting acne, oiliness, or hyperpigmentation. The calculation method you mentioned from another source seems unrelated to achieving a 4% concentration in your batch size.
• 2NA EDTA (0.20%): 0.20% of 1000g is 2g. Your calculation is correct. This is a standard chelating agent for stability.
• Phenoxyethanol (Preservative) (1%): 1% of 1000g is 10g. Your calculation is correct. This is a common preservative used up to 1%.

Summary and Recommendations:

Assuming you intended a 1000g total batch size and want to use the percentages you listed:

• Your calculations for NAG, B3, B5, Zinc PCA, 2NA EDTA, and Phenoxyethanol are correct based on a 1000g total batch.
• The calculation for DMAE is incorrect. To achieve 4% DMAE in a 1000g batch, you would need 40g, not 10.10g.
• The ingredients NAG, B3, B5, and Zinc PCA are well-suited for your skin concerns. DMAE is less directly relevant to acne, oiliness, or hyperpigmentation. Consider if you truly need DMAE for its firming benefits, or if you might omit it or replace it with something else more focused on your primary goals.
• The amount of water needed will be the remaining weight to reach 1000g after adding all other ingredients.

Corrected Weights for a 1000g Total Batch (assuming you keep all ingredients at your stated percentages):

• NAG (2%): 20 g
• B3 (4%): 40 g
• B5 (5%): 50 g
• Zinc PCA (1%): 10 g
• DMAE (4%): 40 g
• 2NA EDTA (0.20%): 2 g
• Phenoxyethanol (1%): 10 g
• Total of above: 20 + 40 + 50 + 10 + 40 + 2 + 10 = 172 g
• Water: 1000 g - 172 g = 828 g

So, for a 1000g total batch with your desired percentages (including 4% DMAE), you would use 828g of water.

If you decide not to include DMAE:

• Total of other ingredients: 20 + 40 + 50 + 10 + 2 + 10 = 132 g
• Water: 1000 g - 132 g = 868 g

This formulation (without DMAE) would be highly targeted towards your stated concerns.

Please double-check your intention regarding the total batch size and the inclusion of DMAE.