Formulation Questions Answered

Here are the answers to your formulation questions:

1. Impact of Powders on Oil-Soluble Actives and Penetration Enhancers

Using oil-absorbing powders like Powder Cream and Matte Silica to improve the skin feel of a formulation for oily skin can potentially impact the efficacy of oil-soluble active ingredients (such as Activated Resorcinol, MSH White, Kojic Acid Dipalmitate, and Sym-White) and penetration enhancers (like PE-1 Aqua or LipidSoft Lite used as a solvent).

These powders work by absorbing the oil phase of the formulation, which is where your oil-soluble actives and penetration enhancers are dissolved. When the oil vehicle is absorbed by the powder, it can make the active ingredients less available to penetrate the skin, potentially reducing their effectiveness. The function of a penetration enhancer, which relies on the vehicle to carry the actives into the skin, may also be diminished.

There is a trade-off between achieving a dry, non-greasy skin feel and ensuring optimal delivery of oil-soluble actives. To minimize the impact on efficacy while still improving skin feel, consider:

• Using the lowest effective concentration of oil-absorbing powders.
• Exploring different types of powders. Some treated silicas, like MatteSilica S (Dimethicone coated), might offer a softer feel, although they still absorb oil. UltraBlur Silica is noted as less oil absorbent, though its primary function is blurring.
• Optimizing the formulation technique to ensure actives are well-dispersed before the powders are incorporated.

2. High Peptide Concentrations in Commercial Products

The observation that some commercial products, like Cream de La Mer and certain US brands, appear to use Argireline, Matrixyl 3000, and Pep-Coll at concentrations exceeding the typical recommended usage rates (e.g., 15% Argireline, 10% Matrixyl 3000) can be attributed to several factors:

• Perceived Increased Efficacy: While raw material suppliers provide recommended usage rates based on their studies, some brands may believe that higher concentrations lead to greater or faster results, even if extensive clinical data at those specific high levels is not publicly available or the increase in efficacy is not linear.
• Marketing Strategy: High percentages of popular active ingredients can be a significant marketing point, appealing to consumers who associate higher concentrations with greater potency or value.
• Complementary Mechanisms: While Matrixyl 3000 and Pep-Coll have similar mechanisms of action (stimulating collagen synthesis), combining peptides with different functions, such as Argireline (which targets muscle contractions) with collagen stimulators, can be a strategy to address multiple aspects of wrinkle formation. Combining with other potent anti-aging ingredients like Retinol is also a common approach, although it's important to consider potential irritation.
• Formulation and Stability: In some complex formulations, higher initial concentrations might be used to ensure a certain level of active remains effective over the product's shelf life, although this is less likely the primary driver for such significantly high percentages.

It's important to note that in the US, the FDA does not set strict percentage limits for most cosmetic ingredients, unlike pharmaceuticals. The responsibility lies with the manufacturer to ensure the safety and proper labeling of their products. Exceeding a supplier's recommended usage rate does not automatically guarantee a proportional increase in efficacy and may increase the risk of skin irritation or sensitivity.

Your previous information regarding Matrixyl 3000 and Pep-Coll having similar mechanisms is generally correct; both are signal peptides that promote collagen production. Combining them might not provide a strictly additive benefit in terms of collagen stimulation compared to using one at its optimal concentration, but formulators might include both for other perceived benefits or marketing.

3. Water-in-Oil EZ Base for Oily Skin with SPF

Water-in-Oil EZ is an emulsifier designed to create water-in-oil (W/O) emulsions. While you can use a lightweight emollient like Isododecane as the oil phase with Water-in-Oil EZ, a W/O emulsion base is generally less suitable for oily skin compared to an oil-in-water (O/W) emulsion.

Here's why:

• Skin Feel: W/O emulsions have an external oil phase, which tends to feel more occlusive, heavier, and potentially greasier on the skin than O/W emulsions, where the external phase is water. This is why W/O emulsions are often recommended for dry skin or use in dry/cold climates, as they provide a good barrier to prevent moisture loss.
• Suitability for SPF: Water-in-oil emulsions are indeed suitable for sunscreen formulations because their water-repellent nature provides good durability and water resistance, which are crucial for SPF products.

While using Isododecane will result in a lighter oil phase compared to heavier oils, the overall feel of a W/Oil emulsion may still be too heavy for someone with oily skin seeking a non-greasy product. If a lightweight, non-greasy feel is the priority for oily skin, an oil-in-water emulsion base is typically a better choice, even for an SPF product. However, if durability and water resistance are the primary goals, a W/O emulsion with a light oil phase like Isododecane using Water-in-Oil EZ can be effective for the SPF function, but the skin feel might not be ideal for all oily skin types.