High-quality ingredients like vitamins and nanoparticles are more sensitive than you think. We spoke with pharmacist Dr. B. Stockebrand about why a single breath of air is enough to start bacterial growth, and why temperature fluctuations can destroy the effect of expensive creams.
Why cooled storage?
biszet: After opening cosmetics, 'cooled storage' is often recommended. Why?
Dr. B. Stockebrand: High-quality cosmetic and care products are manufactured with great care. They contain highly purified ingredients, as germ-free as possible and free of allergens. However, as soon as a tube or jar is opened, a mere breath of air is enough to bring the first bacteria into contact with the ingredients. Further germs are introduced into the substances through use with fingers.
Through oxygen in the air, but above all through temperature effects, these germs can multiply rapidly if the existing preservative system is overwhelmed. However, the trend is towards ever more sparing preservation to keep the burden on the skin as low as possible.
Exponential Bacterial Growth
biszet: How quickly do these germs multiply?
Dr. B. Stockebrand: Microorganisms are known that multiply exponentially with a temperature jump of 10 °C. Storage at 20 °C may cause some bacteria to multiply 30 times faster than storage at only 10 °C.
Loss of Effectiveness through Metabolism
biszet: What influence do bacteria and germs have on the effectiveness of cosmetics?
Dr. B. Stockebrand: Bacteria feed on valuable ingredients. This converts the active substances. New metabolic products are released, such as butyric acid. The content is completely changed. The desired effect is absent, and undesirable effects such as allergies can even occur.
Vitamin A, C and E in Danger
biszet: Which ingredients react particularly sensitively to heat?
Dr. B. Stockebrand: These are mainly vitamins A, C and E. These are contained as so-called antioxidants in many anti-wrinkle creams. They prevent oxidative decomposition processes in the subcutaneous tissue. Because oxidants destroy tissue, collagen fibers of the subcutis change and thus lead to wrinkle formation. This process is prevented by vitamins. However, these are heat-sensitive. The lower the temperature, 'the more comfortable they feel'.
When the Cream Separates
biszet: Significant temperature fluctuations often occur during storage. What do these cause in creams?
Dr. B. Stockebrand: Surely you have observed that creams separate into thick and thin components after some time. This is often the result of temperature fluctuations.
biszet: What happens concretely?
Dr. B. Stockebrand: Temperature fluctuations trigger intense particle movement. Highly complicated systems collapse. The ingredients segregate and are no longer available in the desired composition.
Decay of Nanoparticles
biszet: Why can this make creams ineffective?
Dr. B. Stockebrand: High-quality ingredients are e.g. enveloped by lecithin and channeled as smallest particles (so-called nanoparticles) directly into the subcutaneous tissue of the skin to unfold their anti-aging effect there. All these systems are heat-sensitive, which can lead to these particles simply bursting and the active ingredients no longer reaching their destination in the subcutaneous tissue.
Loss of Sun Protection Factor
biszet: Cooled storage is also recommended to maintain the sun protection factor. Why?
Dr. B. Stockebrand: Many sun protection substances are simply incorporated by the bacteria mentioned. Storage between 20 and 25 °C results in a loss of effectiveness of 5 - 10 % per year. Through cooled storage, the effect is reduced by only a few percent.
Conclusion: The Bathroom is an Imposition
biszet: So do you consider the use of a biszet cabinet to be sensible?
Dr. B. Stockebrand: Yes, I consider storage in a biszet cabinet to be sensible, for all women who want to protect their creams. Because the bathroom is basically – due to its usually warm and humid climate – an imposition for cosmetics. In addition, I recommend removing creams not with fingers, but with a spatula.
Tip: Which temperature is specifically ideal for which skin type is explained by Dermatologist Dr. Kruppa in this interview.
biszet: Thank you very much for the very informative interview.
Dr. B. Stockebrand: You are welcome.