Formulation Assessment

Solubility

Based on the product information, most of the ingredients you listed are water-soluble or dispersible liquids/powders and should dissolve well in a water-based formulation like a "น้ำตบ" (toner/essence).

However, there are a couple of points to note:

• Alaria Esculenta Extract: The description for Alaria Esculenta Extract explicitly states that it is soluble in oil and not soluble in water. At a concentration of 1% in a water-based formula, this ingredient will likely not dissolve and may separate or cause cloudiness.
• Phenoxyethanol SA: This preservative is stated to be soluble in water up to 1.0%. Your proposed concentration is 1.25%. While the presence of Propanediol and Pentylene Glycol may help, it's possible that at this concentration, the Phenoxyethanol SA may not fully dissolve or could affect the clarity and stability of the final product.
• Yeast Resurface: Assuming this refers to a yeast extract like Yeast Radiance or Beta Glucan, these are typically water-soluble or dispersible. Beta Glucan, for instance, disperses in water but may require a slightly viscous formula to prevent settling over time.

Propanediol Concentration

Your formula includes 1,3-Propanediol (Natural) at 10%. According to the product description, Propanediol is used as a humectant, solvent, and preservative booster at a usage rate of 1-20%. Therefore, 10% is well within the recommended usage range and is not considered too high. It will help provide moisture and act as a solvent for other ingredients.

Potential for Irritation

Your formulation includes a significant number of active ingredients, many at or near their maximum recommended usage rates. While each ingredient may offer specific benefits, combining this many actives at high concentrations in a single leave-on product like a "น้ำตบ" significantly increases the overall potential for skin irritation, especially for individuals with sensitive or reactive skin.

Key ingredients in your formula that are known to have a higher potential for irritation, particularly at higher concentrations or in combination with other actives, include:

• Willow Bark Extract (5%): Contains natural Salicylic Acid, which can cause exfoliation and potential dryness or irritation.
• Snail Secretion (8%): Contains Glycolic Acid, which is an alpha hydroxy acid (AHA) that provides exfoliation and can lead to irritation, redness, or sensitivity, especially at higher concentrations or when combined with other exfoliants.
• Niacinamide (5%): While the Safe-B3™ type is designed to reduce flushing, Niacinamide at 5% can still cause temporary redness, warming, or itching in some sensitive individuals.
• Phenoxyethanol SA (1.25%): This preservative is at its maximum recommended concentration. Some individuals may be sensitive to preservatives, and using the maximum level increases this possibility.
• DMI (3%): As a penetration enhancer, DMI helps other ingredients absorb better into the skin. While beneficial for efficacy, it can also increase the penetration of potentially irritating ingredients, thereby increasing their irritating effect.

The cumulative effect of these ingredients, along with others like Scutellaria Baicalensis Root Extract, Palmaria Palmata Extract, Wakame Extract, Ume Extract, Fucus Film, Moist 72, HydroAlgae, and L-Carnosine (which are generally less irritating individually but contribute to the overall complexity and active load of the formula), means that the likelihood of experiencing some level of irritation, redness, stinging, or sensitivity is considerable.

Recommendation

Given the high concentration of multiple active and potentially irritating ingredients, it is highly recommended to perform a patch test on a small, inconspicuous area of skin (such as behind the ear or on the forearm) before applying the product to your face. Observe the area for 24-48 hours for any signs of redness, itching, burning, or other irritation. If irritation occurs, the formula may be too strong for your skin.

You may consider reducing the concentration of some of the more potent actives (like Willow Bark Extract, Snail Secretion, Niacinamide) or using fewer active ingredients in total to create a milder formulation. Additionally, you will need to address the solubility issue with Alaria Esculenta Extract if you wish to include it in a water-based product.