To determine the shelf life of a cosmetic and personal care product, it must undergo stability testing. Products intended for room temperature storage may undergo either accelerated or real-time stability testing.
The most cost and time effective stability testing method the accelerated stability test. Accelerated stability testing is based on the idea that a product exposed to extreme temperatures will degrade at a faster rate when compared to a product at standard (room) temperatures. From the Arrhenius equation), we can calculate that 12 weeks at 40°C is equivalent to 1 year at ambient (room – 21°C) temperature.
Alternatively, we are also able to perform real-time stability testing instead of accelerated stability testing. Rather than subjecting the product to extreme conditions, the product is observed at room temperature. The evaluations are directly equivalent to what the product would look like if it were being sold in a retail setting.
The shelf life of a product tells the customer when an item is no longer considered suitable for sale or use. While stability testing does not have any passing criteria, it provides information for to determine when a product is no longer of sufficient quality or safe for use by the customer.
It is important that the product is tested in its final retail packaging, as the container the product in stored may have an impact on the product’s degradation. If you would like to test whether the final retail packaging affects the degradation of the product, we also provide package compatibility testing. Package compatibility testing also the product in a glass jar alongside the final retail package. Microchem prefers to receive pre-aliquoted test substances, but may aliquot for an additional fee. Typically, if the final retail package is already glass, it is not necessary to perform package compatibility testing alongside stability testing.
For evaluation intervals, it is largely at the discretion of the study sponsor, however we typically suggest 4, 8, and 12-weeks for Accelerated Stability testing and 4, 8, and 12-months for Real-time Stability testing. These intervals allow for snapshots of how the product is doing at the specified intervals before the product reaches its final evaluation time.
Typically, for products not specified below, we suggest all available testing parameters found below:
For anhydrous oils or scrubs, we typically do not suggest pH as some level of water content must be present to obtain a value for pH.
For anhydrous deodorants or balms, we are unable to obtain data for pH or Viscosity due to the solid nature of the product.
If you would like to determine if your product degrades based on the light conditions, we also provide photostability testing.