Questions about Oil Blend Formulation: pH, High Concentration, and UV Protection

Okay, I see you've experimented with making your own oil blend similar to Bio-Oil and had a good experience! That's great that it worked well for you. Let's address your specific questions based on your proposed formula: Jojoba Oil + Rose Hip Oil base with 6% Pro-Niacin, 5% Perfect-C™, 2% SKIN-DEFENSE® V, 10% Capryloyl Salicylic Acid, 5% Horse Oil, and 0.1% Protec™ UV.

1. Regarding pH and LHA for Perfect-C™: You are correct that pH is typically measured in water-based solutions, not pure oils. The recommended pH range of 3-6 for Perfect-C™ (Ascorbyl Tetraisopalmitate) applies when it's used in formulations containing water. Since your formula is entirely oil-based, pH is not a relevant factor for the stability or efficacy of Perfect-C™. Capryloyl Salicylic Acid (LHA) is oil-soluble and acts as an exfoliant in oil formulations, but it doesn't function to adjust pH in this context.
2. Regarding Concentration Suitability: Your formula uses significantly higher concentrations of active ingredients compared to the original Bio-Oil, which lists its active botanical extracts and vitamins much lower down its ingredient list (indicating lower percentages). While you found the texture acceptable and absorption good, using high concentrations like 10% Capryloyl Salicylic Acid and 6% Pro-Niacin (Myristyl Nicotinate) can potentially cause skin irritation, redness, or sensitivity, especially with regular use on the face. If you experience any irritation, you might consider reducing the concentration of these potent actives.
3. Regarding Protec™ UV and Bottle Type: Protec™ UV (Benzotriazolyl Dodecyl p-Cresol) is added to help protect the formula itself from UV degradation, improving its stability. While it offers protection, it doesn't make the formula completely immune to light damage. An amber or opaque bottle is generally recommended for oil-based products and formulations containing potentially light-sensitive ingredients (like some oils or actives) as it provides an extra layer of protection against light exposure, helping to maintain the product's quality and lifespan. While not strictly mandatory if you store the product carefully away from light, an amber bottle offers better long-term stability assurance.

It's great that your experimental batch turned out well! Just be mindful of the high active concentrations and watch for any signs of irritation on your skin.