Start with Crystal Retinal 3 if you have used a retinoid before, and Crystal Retinal 1 if you have not, or if your skin runs sensitive. Stay on each strength until you have finished the tube without irritation, then move one step up. That is the whole system. The rest of this guide explains why it works, what each strength is for, and how to climb without the flaking and redness that make people give up on vitamin A.
What the numbers actually mean
Medik8's Crystal Retinal range runs from 1 to 20, and the number tracks the concentration of retinaldehyde in the formula: 0.01%, 0.03%, 0.06%, 0.1% and 0.2%. Each step is roughly 1.5 to 3x the active dose of the step below it, which is why the ladder is climbed one rung at a time rather than jumped.
Retinaldehyde, usually shortened to retinal, is not the same molecule as retinol. Skin converts every form of vitamin A into retinoic acid before it can act. Retinol needs two conversion steps to get there. Retinaldehyde needs one. That single missing step is the reason Medik8's research describes retinal acting up to eleven times faster than retinol at a comparable level of tolerance. The Crystal in the name refers to the encapsulation that stabilises the molecule, a real problem for retinal historically, and releases it gradually through the night.
With consistent use, the visible results are the ones vitamin A is known for: fine lines appear softened, tone looks more even, texture feels smoother, and skin that leans congested often looks clearer.
The ladder, rung by rung
Crystal Retinal 1 · 0.01% · $89
The entry point. Choose it if you have never used a retinoid, if your skin is reactive or barrier-prone, or if a previous attempt at vitamin A ended in irritation. There is no prize for skipping this rung. A full tube of 1, tolerated well, sets up everything that follows.
Crystal Retinal 3 · 0.03% · $99
The most common starting point in practice. Suits skin that has already handled a retinol serum, or resilient skin starting vitamin A for the first time. Most people stay here for one to two tubes before stepping up.
Crystal Retinal 6 · 0.06% · $135
The bestseller in the range, and the strength many people settle at long term. This is a working dose: meaningful visible change with tolerability that suits nightly use once skin is acclimatised. If you arrive here and are happy with what you see, there is no obligation to keep climbing.
Crystal Retinal 10 · 0.1% · $176
For experienced vitamin A users whose skin has fully adapted to 6 and wants more. At this strength, technique matters: dry skin, a measured amount, and a moisturiser that supports the barrier on the nights in between.
Crystal Retinal 20 · 0.2% · $195
The ceiling of the range and among the highest strengths in the range available. It is for skin that has genuinely finished a tube of 10 without complaint, not for ambition. Very few people need it, and nobody should start on it.
The eye area has its own ladder
The skin around the eyes is thinner and more reactive, so the face serums stay away from the orbital bone. Crystal Retinal Ceramide Eye 3 ($85) and Ceramide Eye 6 ($109) pair the same encapsulated retinal with ceramides so the eye area can climb its own two rungs safely.
How to climb
- Finish the tube first. A 30ml tube used correctly lasts roughly ten to twelve weeks. That is also about how long skin needs to fully adapt to a strength. One tube per rung is the minimum, and staying longer costs you nothing.
- Move up only if the current strength has become uneventful. No stinging, no flaking, no tightness in the days after use. If a strength still announces itself, it is still working on you.
- Step down without shame. Seasons, travel and in-clinic treatments all change what skin tolerates. Dropping back a rung for a tube is good technique, not failure.
How to use it, whatever the strength
- Night only. Vitamin A belongs in the evening routine. Daylight is for vitamin C and sunscreen.
- Start two to three nights a week on clean, fully dry skin, and build to nightly as tolerance allows.
- A pea-sized amount covers the face. More product does not mean faster results, only a harder adaptation.
- Buffer if you need to. Applying moisturiser first, or sandwiching the retinal between two layers of it, softens the experience without switching it off.
- Keep exfoliating acids on different nights while you are adapting. Our guide to layering actives covers the full traffic rules.
- Wear SPF every morning. Retinoids make daily sun protection non-negotiable, and unprotected sun exposure undoes the work.
Frequently asked questions
Which Crystal Retinal strength should I start with?
Crystal Retinal 1 if you are new to retinoids or have sensitive skin. Crystal Retinal 3 if you have used retinol before and tolerated it. Almost nobody should start above 3.
How long before I see results?
Because retinal sits one conversion step from retinoic acid, early changes in texture and clarity often show within four to eight weeks, with the fuller picture usually developing over three to six months of consistent use.
Is retinal better than retinol?
It reaches the same end point faster. Retinol remains a well-tolerated and well-studied route, and we stock strong retinol formulas for skin that prefers it. If you are weighing two retinol strengths instead, we have written about which comes first.
Do I ever need to reach Crystal Retinal 20?
No. The right strength is the highest one your skin accepts without protest, used consistently. For many people that is 6, and the results at 6 over years outperform the results of 20 used in stops and starts.
Can I use Crystal Retinal while pregnant or breastfeeding?
Vitamin A is conventionally set aside during pregnancy and breastfeeding. If that applies to you, speak with your doctor, and our clinical team can suggest what to use in the meantime.
My skin is flaking. Should I stop?
Reduce frequency rather than abandoning it. Two nights a week with generous moisturiser usually settles adaptation within a fortnight. If irritation persists, drop down a strength.
Unsure where you sit on the ladder? Our retinoid quiz will place you, or ask our clinical team via the contact page.
