Combining Hydroxypinacolone Retinoate (HPR) and Retinaldehyde

Based on your understanding, Hydroxypinacolone Retinoate (HPR), such as Perfect-A 99™, Perfect-A 10™, and Perfect-A Nano™, is a next-generation retinoid that can directly interact with retinoid receptors in the skin without needing conversion steps like traditional retinoids. It is known for its effectiveness, better stability, and lower irritation potential compared to Retinol.

Retinaldehyde, available as Retinal (Retinaldehyde) or Retinal-EZ™, is another potent form of Vitamin A that converts to Retinoic Acid in a single step in the skin. It is highly effective but generally less stable than HPR and can cause more irritation than HPR, although less than Retinol.

Regarding your question about combining HPR and Retinaldehyde in the same formula: Yes, it is technically possible to include both ingredients in a single formulation.

Here are some points to consider when combining them:

• Potential Synergy: Combining these two forms might offer a synergistic effect, leveraging HPR's direct action and Retinaldehyde's efficient conversion pathway to potentially enhance anti-aging benefits.
• Increased Efficacy vs. Irritation: While the goal is often enhanced efficacy, combining two potent actives also increases the potential for skin irritation, redness, and peeling, especially for sensitive skin types. Even though HPR is less irritating than Retinaldehyde, the combined effect needs careful consideration.
• Formulation Stability: Retinaldehyde is less stable than HPR and is sensitive to light, heat, and air. Formulating with both requires careful attention to the overall stability of the product. Using stabilizers like Protec™ OX, Protec™ UV, Protec™ SQ, or Bakuchiol, as recommended for Retinaldehyde, would be crucial.
• Concentration: If you choose to combine them, it is highly recommended to start with lower concentrations of each ingredient than you might use individually to assess skin tolerance.
• Supporting Ingredients: Including soothing and barrier-supporting ingredients, such as Vitamin B3 (Niacinamide), which is mentioned as beneficial when using Retinaldehyde to reduce irritation, can help improve tolerance.

In summary, while there isn't extensive research specifically on the combined use of HPR and Retinaldehyde compared to individual use, it is chemically feasible to formulate with both. However, it requires careful formulation expertise to manage potential irritation and ensure product stability. Always perform patch testing and consider consulting with a formulation chemist.