Lip Balm Formulation Questions

Here are the answers to your questions regarding lip balm formulation:

Phenoxyethanol in Lip Balm

Generally, good lip balm or lipstick formulas should not contain water. If there is no water component, preservatives are not necessary. It is advisable to avoid preservatives in lip products if possible, even if some are approved for oral use by regulatory bodies.

Preventing Rancidity (Oxidation)

The issue of oils like grape seed oil and sweet almond oil becoming rancid after a few months is due to oxidation (free radical formation) of the natural ingredients, not microbial spoilage. To extend the shelf life and prevent oxidation, you can:

1. Add antioxidants such as Vitamin E (like Vitamin E Acetate or dl-alpha tocopherol) and Rosemary Oleoresin Extract (ROE).
2. Avoid using high heat during the mixing process, as heat significantly accelerates the degradation of natural oils.
3. Choose natural oils with higher stability and longer shelf life, such as Jojoba Oil, and minimize or avoid oils that degrade quickly like grape seed oil.

Effectiveness of Vitamin E for Oxidation Prevention

Adding Vitamin E helps slow down the oxidation process. However, it is not possible to give an exact percentage of how much it extends the shelf life. This depends on several factors, including the type of oil used, the specific type of Vitamin E, and the degree of oxidation that has already occurred in the oil before the Vitamin E is added. You can generally expect an extension of around 3 months for oils that typically have a 6-12 month shelf life, and potentially more for oils that are inherently more stable. It is most effective when added as early as possible, before significant oxidation has occurred, as oxidation is a chain reaction.

Stability Ranking of Base Oils

Your proposed ranking of oil stability when stored at room temperature away from light (Sesame > Sweet Almond > Olive > Grape Seed > Coconut) is likely close on average. However, the actual stability can vary significantly depending on many factors, including the processing method (e.g., cold-pressed vs. refined) and the conditions during transportation and storage before the oil reaches the consumer. Since these are natural products, there will always be some variation between batches.