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How effective is your retinol product?

Retinoids have a scientifically proven positive effect on our skin, but how much of the promised benefits are you actually getting from your skin care product? Among other things, retinoids have been shown to improve our skin texture and skin tone and are therefore very popular ingredients in skin care products. But few skin care users know that retinoids are extremely sensitive and can lose effectiveness over time if storage conditions are not optimal. Simply put, you may not be getting the benefits your skin care product actually promises.

The challenges of maintaining the effectiveness of retinoids are demonstrated in the study "Retinoids stability and degradation kinetics in commercial cosmetic products" published in November 2020. In this study, in which long-term stability tests were performed on a number of skin care products, clear retinoid instability is seen in almost all tested products, resulting in a 0% – 80% reduction after 6 months at 25°C and a 40% – 100% reduction at 40°C. This is a recent and very interesting study that shows 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) as well as carotenoids with vitamin A activity (Beta-carotene). Retinoids are widely used in skin care and pharmaceuticals because they are effective against signs of aging, acne, psoriasis and other conditions, and are among the most studied substances in dermatology and the cosmetics industry.

Are there any downsides to using retinoids?

The biggest problem with retinoids in skin care is that many retinoids are very sensitive to temperature increases (even room temperature), water, light and oxygen (air). This simple fact means that retinoids are not always suitable as ingredients in what we call traditional skin care . Traditional skin care usually has a long shelf life (30 months), can be stored at room temperature and comes in packaging such as open cans where the product is exposed to air.

This fact results in two main problems:

  1. Degradation of retinoids results in less effective products
  2. When retinoids are broken down, by-products are formed and there is currently uncertainty about whether these by-products affect your skin

How stable retinoids are in skin care products depends on several factors:

  • What type of wording it is, e.g. an oil or a cream. Some formulation types make the retinoids extra sensitive
  • The pH value of the formulation
  • The presence of antioxidants and stabilizers (tocopherol, citric acid, BHT, etc.). Stabilizers are often used to stabilize retinoids but may not always be the best ingredients from a skin health perspective
  • Packaging type (a clear jar allows retinoids to 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 investigated 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 degrade (disintegrate) 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 degraded in almost all products, both at room temperature (0-80% degradation) and at 40°C (40-100% degradation). Retinol and Retinyl palmitate were similarly degraded, beta-carotene was slightly 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 shorter than 1 month. At 40°C, shelf life was on average shorter than 14 days. All products promised a shelf life of 6 or 12 months after opening, which simply turned out 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 was degraded.

How does light exposure affect the different retinoids?

The researchers also studied retinoid photosensitivity in the products, meaning how sensitive the formulations are to light. Here, Retinol outperformed the other types and was found to be the least sensitive to light (64-90% remaining). Retinyl palmitate and Beta-carotene were degraded almost completely and Hydroxypinacolon retinoate was degraded by 40%.

What does this actually say?

This study highlights how unstable retinoids are. In many of the products from the study, the actual retinoid concentration was much lower than what was stated on the packaging and the shelf life after opening was also significantly shorter than what was declared by the respective skin care 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 opaque airless packaging to avoid light and oxidation of the formulation. We have also developed a unique formulation with a very low water content to further stabilize the retinol. As you can see in the study, the level of degradation is very dependent on temperature and thanks to our cold logistics chain and asking our customers to store the products in the refrigerator, we ensure that the retinoid used in our Night Active Retinol (skin-friendly retinol) provides maximum effect. In addition to this, we have a shorter shelf life on all our freshly produced products to ensure that all active ingredients, not just retinol, are effective. Together, these measures ensure you get the most out of your Skinome formulation.