Preventing Rancidity in Your Homemade Cream

The off smell you are experiencing after a few weeks is likely due to the oils in your cream going rancid, which is caused by oxidation, not microbial spoilage. The previous reply you received correctly identified this.

To prevent your Jojoba Oil and Apricot Kernel Oil from oxidizing and causing rancidity, you should add an antioxidant to your formulation. A common and effective antioxidant for oils in cosmetic formulations is Vitamin E.

Recommendation:

Add Vitamin E (Tocopherol) to the oil phase of your cream formulation. A typical usage rate for Vitamin E when used specifically as an antioxidant to protect oils is around 0.01% to 0.5% of the total formula. Adding it at this concentration will help extend the shelf life of your cream by protecting the oils from oxidation.

Regarding your other questions:

• Amway Filtered Water: Using filtered water from your Amway machine is not the cause of the rancidity. As mentioned in the reply you received, this type of filtration is for drinking water and may still contain minerals, but it does not cause oils to go rancid. For cosmetic formulations, using purified or distilled water is generally recommended, but the filtered water is not the source of your current problem.
• Phenoxyethanol Concentration: Your usage of Phenoxyethanol at approximately 1% is sufficient for preserving the cream against microbial growth. Increasing the concentration of Phenoxyethanol would not prevent oil rancidity and could potentially cause skin irritation, as noted in the previous reply.

In summary, incorporating a small amount of Vitamin E into your oil phase is the best way to prevent the rancid smell and improve the stability of your cream formulation.

Remember to also store your finished cream in a cool, dark place and minimize exposure to air to further protect the oils from oxidation.