Shelf Life of Alcohol Spray Formulation

Here's an assessment of the shelf life for your alcohol spray formulations:

1. Formulation without Preservative

Your formulation contains 70g of 95% alcohol, 6g of Glycerin, 0.5g of fragrance, and 23.5g of water (to reach 100g total). While the high concentration of alcohol (approximately 66.5% pure alcohol) provides some antimicrobial properties, the presence of water, Glycerin, and fragrance makes the product susceptible to microbial contamination over time, especially after opening. Without a dedicated broad-spectrum preservative, the shelf life of this formulation would be limited. You can expect it to last typically only a few months from the production date (January 1, 2020), depending on storage conditions and handling. It is highly recommended to use a preservative for water-containing formulations to ensure safety and extend shelf life.

2. Formulation with DMDM Hydantoin

By adding 0.5g of DMDM Hydantoin to your 100g formulation (which is 0.5%), you are introducing a broad-spectrum preservative. DMDM Hydantoin is effective against bacteria, yeast, and mold and is commonly used in rinse-off and leave-on cosmetic products within the allowed concentration limits (typically up to 0.6%). The addition of this preservative significantly enhances the microbial stability of your product. With the inclusion of DMDM Hydantoin at 0.5%, combined with the high alcohol content, the shelf life of your alcohol spray formulation produced on January 1, 2020, would be extended. You can generally expect a shelf life of 2-3 years when stored properly in a sealed container away from heat and direct sunlight.

Adding a suitable preservative is crucial for the safety and longevity of cosmetic products containing a water phase.