Crystal Retinal 24.

"Retinol is my personal favorite. This is 20% stronger than the next equivalent strength and it packs a punch. I absolutely love it and it's just my personal favorite."

"It doesn't get stronger than this. I love the fact that it's encapsulated, which is going to reduce the risk of any side effects and irritation. And I like the fact that they've packed this full of antioxidants and hydrators to minimize the risk of any dryness or peeling, flaking that you might experience. For the lovers of Medik8 out there that have tried the Medik8 Crystal Retinal line but want to go for the highest option, I would fully recommend this. It's roughly 20% stronger than their next one down, so that's a big jump. But as long as you've gradually gone up through the gradients, you should have no problem incorporating this."

"I've been using this product for the past month. I'm an established retinoid user I've been using them for the past 6 years and so I didn't expect to see a whole lot of change with this product so I was pleasantly surprised when I genuinely did. I started to see the emergence of fine lines and wrinkles around the crow's feet, around the laughter lines and the 11s. I've also noticed a little bit of loss of firmness around the jawline. Whilst the results I saw from this weren't like transformative and game-changing, they were noticeable enough that I could see them with my own naked eye when I looked in the mirror. One thing I did notice though is I did see an increase in dryness, sensitivity and irritation. That should be expected after all, I'm using a roughly 20% higher dose of retinoids in this versus what I was using before. With a higher concentration you usually will see an increase in side effects and irritation. It wasn't particularly unpleasant or anything really to suggest that you shouldn't be using it but it's definitely something to be aware of. I think this is the sort of product that really should only be used by people that are established retinoid users, having incorporated them successfully probably for the past 12 months. I wasn't wildly impressed with the price point."

"I noticed a little bit of loss of firmness around the jawline, and while the results I saw from this weren't transformative and game-changing, they were noticeable enough that I could see them with my own naked eye when I looked in the mirror. I did see an increase in dryness, sensitivity, and irritation, which maybe should be expected after all I'm using a roughly 20% higher dose of retinoids in this versus what I was using before. With a higher concentration you usually will see an increase in side effects and irritation. It wasn't particularly unpleasant or anything really to suggest that you shouldn't be using it, but it's definitely something to be aware of. I think this is the sort of product that really should only be used by people that are established retinoid users. I wasn't wildly impressed with the price point. When I'm used to shopping at geek and gorgeous, this version is something in the region of £18, so splurging £109 for roughly 20% higher concentration did seem like a lot of additional expense. However, I have kind of been impressed with the results. Retinal works so effectively in comparison to retinol because it's closer to the retinoic acid our skin needs."

"I've been working through two of their retinol products. This is the Crystal Retinal 24 and their eye cream with retinaldehyde. One conversion away from the prescription formula tretinoin. Love both of these. They are a little bit on the colorful side. So you may want to consider letting this dry down for at least a half an hour before you jump into your white satin sheets."

"I've been able to tolerate the retin by Medik8. This is their 24 Crystal Retinal, their strongest that they make, but I've honestly been able to tolerate it even over the Tria laser treatments. I'm on level three and I've been doing it about five times a week."