As a chemistry student with a growing obsession with skincare, I found myself asking: what's so special about Medik8's Crystal Retinal? Retinoids are everywhere- so why does this one get so much hype from dermatologists and consumers? Well, here I take my unique perspective as an aspiring chemist to dive deep into the molecules, the formulation, and the chemistry that makes up the UK’s No.1 dermatological face serum.
WHAT IS RETINAL
Let's start by having a look into what retinal is and what the Medik8 Crystal Retinal claims to do. Retinaldehyde (retinal) is a form of vitamin A which works directly to reduce fine lines, improve texture, and boost collagen. Medik8’s Crystal Retinal serum encapsulates retinaldehyde in a patented crystal‑shaped delivery system, which releases the ingredient gradually overnight. This design stabilises the molecule and minimises sensitivity.
According to clinical data, a single tube, particularly the popular Crystal Retinal 6, can reduce visible wrinkles by around 20%, boost skin firmness by approximately 11%, and show improvements in tone, texture, and clarity in as little as seven days, all while being gentle enough for sensitive skin. Retinal even has antibacterial properties which are perfect for tackling acne-prone skin by fighting against cutibacterium acne primarily responsible for acne development.
RETINOL VS RETINAL
At first glance, retinal is based upon vitamin A, similar to retinol. However, one of the most fascinating things about vitamin A in skincare is that it doesn’t start out in its active form. Retinol, commonly used in over-the-counter products, goes through two organic reactions in the skin to become retinoic acid, which is the form that actually triggers cellular renewal. Each step slows down the process and, therefore, reduces its potency.
That’s why Medik8’s use of retinal is an effective way of skipping that first conversion step so that the product delivers a molecule that’s already one step closer to being active. Thus, making it faster and more effective. From a chemistry standpoint, it’s like cutting out the middleman in a reaction mechanism. The challenge, of course, is that retinal is notoriously unstable. However, Medik8’s crystal-encapsulation technique helps protect it until it reaches the skin. Fig 1. Conversions of retinol.
STRENGTHS
One of the things I appreciate most about Medik8’s Crystal Retinal line is its graduated strength system, which ranges from Crystal Retinal 1 (0.01%) for very sensitive or beginner skin, up to Crystal Retinal 20 (0.24%) for more experienced users.
The tiered approach allows the skin to adjust slowly to the cream, reducing the risk of irritation and improving long-term tolerability. The lower strengths are ideal for those new to vitamin A or with sensitive skin, offering gentle but effective results over time. The higher strengths, on the other hand, deliver faster and more visible changes in texture and tone, but they do come with a higher risk of dryness and sensitivity.
It’s essentially a balance between speed and comfort, and the step-up system lets users personalise their routine based on their skin’s resilience and goals. From a formulation perspective, it’s a controlled way to introduce a powerful molecule without overwhelming the skin.
Taking a deep dive into the other active ingredients in the Medik8 Crystal Retinal, it is clear that the formula is designed to enhance performance and minimise irritation.
Glycerin and hyaluronic acid provide multi-level hydration as they draw moisture into the skin and help to maintain a plump, healthy complexion.
Squalane, an anti-aging emollient, helps to strengthen the skin’s barrier, reducing the risk of dryness or flaking.
Meanwhile, vitamin E (tocopherol) offers antioxidant protection and helps to stabilise the formula overall.
These ingredients are incredibly beneficial in creating a gentle and soothing experience. It’s a great example of how carefully chosen ingredients can make high-performance skincare more tolerable and balanced.
SENSITIVITY AND STABILITY
Like all vitamin A derivatives, this formula can increase your skin’s sensitivity, particularly to sunlight, which is why nighttime application and diligent sunscreen use during the day are essential.
Another important factor is that vitamin A compounds, especially retinal, are not photostable, meaning they can degrade and lose potency when exposed to light. This instability poses a major formulation challenge. Fortunately, Medik8 addresses it with their crystal encapsulation technology, which helps protect the active ingredient until it’s applied to the skin. From a chemistry perspective, it’s a clever way to slow down degradation and preserve efficacy, while also allowing for gradual release to minimise irritation.
Medik8 Crystal Retinal is also formulated with a time-release delivery system that allows the active compounds to be released gradually over several hours throughout the night, rather than all at once. This sustained delivery helps maintain a more stable concentration of retinal across the skin barrier, reducing the likelihood of irritation.
SUMMARY
Studying chemistry hasn’t just made me more critical of what’s in my skincare; it’s made me more appreciative when a brand has a smart formulation built on real science. The Medik8 Crystal Retinal has given me a new respect for how skincare can bridge the gap between lab research and customer satisfaction. Whilst addressing common challenges like irritation and instability through encapsulation and a tiered strength system, the Medik8 Crystal Retinal provides a structured way to gradually build tolerance and see meaningful results over time.
Usual cautions that come with vitamin A such as increased sensitivity and the need for daily sun protection are present but for those looking to incorporate a more advanced form of vitamin A into their routine, it is a well-formulated option with a clear science behind it.
REFERENCES
Leroy, C. (2024). Circana Group Claim Letters - Crystal Retinal. [online] Medik8. Available at: https://www.medik8.com/pages/circana-group-claim-letters-crystal-retinal [Accessed 12 Jun. 2025]
Medik8-EU. (2015). Retinaldehyde Skincare: What Is It? How to Use It & Benefits. [online] Available at: https://eu.medik8.com/pages/retinaldehyde-skincare-what-is-it-how-to-use-it-benefits [Accessed 13 Jun. 2025].
Pechère, M., Pechère, J.C., Siegenthaler, G., Germanier, L. and Saurat, J.H. (1999). Antibacterial activity of retinaldehyde against Propionibacterium acnes. Dermatology (Basel, Switzerland), [online] 199 Suppl 1, pp.29–31. doi:https://doi.org/10.1159/000051375.
Cochran, M. (2024). The Difference Between Retinol And Retinal. [online] Go-To Skincare. Available at: https://uk.gotoskincare.com/blogs/the-go-to-guide/what-is-the-difference-between-retinol-and-retinal?shpx id=e233d4cc-e47f-4b14-aae6-c5c8fd173e41[Accessed 12 Jun. 2025].
Siegenthaler, G., Jean‐Hilaire Saurat and Ponec, M. (1990). Retinol and retinal metabolism. Relationship to the state of differentiation of cultured human keratinocytes. Biochemical Journal, 268(2), pp.371–378. doi:https://doi.org/10.1042/bj2680371. Incidecoder.com. (2019).
