Retinoids have a scientifically proven positive effect on our skin, but how much of the promised benefits do you actually get from your skin care product? Retinoids have been shown to improve our skin texture and tone, among other things, and are therefore very popular ingredients in skincare products. But few skincare users know that retinoids are extremely sensitive and can lose their effectiveness over time if storage conditions are not optimal. Simply put, you may not get the benefits that your skincare product actually promises.
The challenges of maintaining retinoid efficacy are demonstrated in the study "Retinoids stability and degradation kinetics in commercial cosmetic products" published in November 2020. This study, which conducted long-term stability tests on a number of skin care products, sees clear retinoid instability in almost all products tested, resulting in a 0% - 80% reduction after 6 months at 25°C and 40% -100% reduction at 40°C. This is a recent and very interesting study showing similar results to Skinome's own studies on retinoids.
What are retinoids and why are they used?
Retinoids refer to: Retinol (= vitamin A) and its analogues (e.g. Retinyl palmitate) and carotenoids with vitamin A activity (Beta-carotene). Retinoids are widely used in skin care and drugs because they are effective against signs of aging, acne, psoriasis and other conditions and are among the most studied topics in dermatology and the cosmetics industry.
Are there any downsides of using retinoids?
The main issue with retinoids in skincare is that many retinoids are very sensitive to increased temperatures (even room temperature), water, light and oxygen (air). This simple fact makes retinoids not always suitable as ingredients for what we call traditional skincare. Traditional skincare typically has a long shelf life (30 months), can be stored in room temperature and comes in packaging like e.g. open jars where the formula gets exposed to air.
This fact results in two main problems:
- Degradation of retinoids results in less effective product
- When retinoids are broken down, by-products are formed and there are currently uncertainties as to whether these by-products affect your skin
How stable retinoids are in skincare products will depend on many factors:
- What type of formulation it is (e.g. an oil or a cream). Some formulation types make the retinoids more sensitive
- The formula’s pH-value
- Presence of antioxidants and stabilizers (Tocopherol, Citric acid, BHT, etc.). Stabilizers are often used to stabilize retinoids but might not always be the best ingredients from a skin health perspective
- Packaging type (a clear jar will let retinoids break down faster than in an opaque airless pump)
- Storage conditions (room temperature or warmer/cooler)
How stable are retinoids in skin care?
In the study "Retinoids stability and degradation kinetics in commercial cosmetic products", the researchers examined the stability of 16 retinoid derivatives in 12 cosmetic products (some products contained more than one type of retinoid). The types of retinoids included in the study are:
- Retinol
- Retinyl palmitate
- Hydroxypinacolone retinoate
- Beta carotene
They looked at how quickly the retinoids break down (decompose) in the formulations both at room temperature (25°C and 60% relative humidity) and at elevated temperature (40°C and 75% relative humidity). The results showed that the retinoids were broken down in almost all products, both at room temperature (0-80% degradation) and at 40°C (40-100% degradation). Retinol and Retinyl palmitate was similarly broken down, beta-carotene was a little more stable and the most stable form was Hydroxypinacolone retinoate.
The study showed that the average shelf life (= at least 90% of the retinoid remained in the product) was only 2 months. In one third of the tested products, the shelf life was less than 1 month. At 40 °C the shelf life was on average less than 14 days. All these products declared to have a shelf life of 6 or 12 months after opening, which simply showed not to be true. It was clear that temperature affected how much retinoid remained in the product.
The researchers also found when examining the 12 products that it was clear that the type of formulation, not concentration or price, had the greatest impact on the level of degradation. In other words, what other ingredients were used and how the product was formulated was more important than the concentration of retinoid in the product. They also found that the higher the concentration of retinoid, the more degraded.
How does light exposure affect the different retinoids?
They also studied retinoid photosensitivity in the products, meaning how sensitive the formulations are to light. Here, Retinol outperformed the other types and showed to be the least sensitive to light (64-90% remained). Retinyl palmitate and Beta carotene degraded almost completely and Hydroxypinacolone retinoate degraded by 40%.
What does this tell us?
This study highlights how unstable retinoids are. In many of the products from the actual retinoid concentration was much lower than stated on the packaging and the shelf life after opening was also significantly shorter than that declared by the respective skincare brand.
What do we do at Skinome to ensure you get the right concentration of retinoids?
At Skinome, we counteract the problems explained in the article by using an opaque airless package to avoid light and oxidation of the formulation. We have also developed a unique formulation with very low water content to further stabilize the retinol. As you can see from the study, the level of degradation is very much dependent on temperature and thanks to our cold logistics chain and asking our customers to store the products in the fridge, we ensure that the retinoid used in our Night Active Retinol (skin endogenous retinol ) provides maximum efficacy. In addition, we have a shorter sustainability on all our freshly produced products to ensure that all active ingredients, not just retinol, are effective. Together, these measures ensure that you get the most out of your Skinome formulation.
