If you're considering Medik8 Crystal Retinal but aren't sure whether to choose Crystal Retinal 1, 3, 6, 10, 20 or 24, you're not alone.
One of the advantages of Medik8's bestselling vitamin A serum is its progressive strength system. Rather than taking a one-size-fits-all approach to retinal, Medik8 Crystal Retinal is available in six strengths, allowing you to choose a formula according to your previous vitamin A experience and gradually progress as your skin builds tolerance.
But does everyone need to work their way up to Crystal Retinal 24? And should you start with Crystal Retinal 1 or 3 if you've never used a retinoid before?
As a doctor working within aesthetics and skin health, my approach is simple: the strongest retinoid isn't necessarily the best retinoid for your skin.
Consistency and tolerance matter.
In this guide, we'll explain the differences between Medik8 Crystal Retinal 1, 3, 6, 10, 20 and 24, who each strength may be suitable for and how to introduce retinal into your skincare routine.
Shop Medik8 Crystal Retinal at Villa Skincare →
What is Medik8 Crystal Retinal?
Medik8 Crystal Retinal is an overnight vitamin A serum formulated with retinaldehyde, commonly known as retinal.
Retinal belongs to the retinoid family alongside retinol and prescription retinoids.
Retinoids are widely used within skincare routines targeting concerns such as:
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Fine lines and wrinkles
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Uneven skin texture
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Hyperpigmentation
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Post-acne marks
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Blemishes and congestion
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Dullness
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Visible signs of photoageing
Crystal Retinal has become one of Medik8's best-known products partly because it combines retinal with a progressive strength system, allowing users to move through increasingly concentrated formulations as their skin becomes accustomed to vitamin A.
If you're new to Medik8 as a brand, you can also read our Complete Guide to Medik8 Skincare.
Explore the complete Medik8 skincare collection →
Retinal vs retinol: what's the difference?
Although the names sound similar, retinal and retinol aren't exactly the same thing.
Both are vitamin A derivatives, but they sit at different points within the conversion pathway to retinoic acid – the biologically active form of vitamin A used by the skin.
In simplified terms:
Retinol → Retinaldehyde → Retinoic Acid
Because retinal sits one conversion step closer to retinoic acid than retinol, it is an interesting option for people wanting to progress their vitamin A routine.
However, this doesn't mean everybody should immediately switch to a high-strength retinal.
Your previous experience with vitamin A, skin sensitivity and existing skincare routine all need to be considered.
For a more detailed explanation, read our Retinal vs Retinol vs Prescription Retinoids: Which One Is Right for Your Skin?.
Medik8 Crystal Retinal strengths explained
There are currently six Medik8 Crystal Retinal strengths, ranging from 0.01% retinal in Crystal Retinal 1 to 0.24% in Crystal Retinal 24.
| Crystal Retinal | Retinal Strength | Medik8 Level |
|---|---|---|
| Crystal Retinal 1 | 0.01% | Sensitive |
| Crystal Retinal 3 | 0.03% | Beginner |
| Crystal Retinal 6 | 0.06% | Regular |
| Crystal Retinal 10 | 0.1% | Advanced |
| Crystal Retinal 20 | 0.2% | Experienced |
| Crystal Retinal 24 | 0.24% | Expert |
So, which Medik8 Crystal Retinal should you choose?
Let's look at them individually.
Medik8 Crystal Retinal 1 – Sensitive
0.01% retinal
Crystal Retinal 1 is the lowest strength within the Medik8 Crystal Retinal range.
This may be the most appropriate starting point if:
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You have particularly sensitive skin
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You've never used vitamin A before
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You've previously struggled to tolerate retinol
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You want to introduce retinal very gradually
Starting lower doesn't mean you're doing anything wrong.
If anything, establishing a product that your skin tolerates consistently can be much more useful than choosing an unnecessarily high strength that leaves your skin irritated.
Medik8 Crystal Retinal 3 – Beginner
0.03% retinal
Crystal Retinal 3 is Medik8's beginner strength and is likely to be the starting point many people consider when first introducing retinal.
It may be appropriate if:
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You're new to retinal
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Your skin isn't particularly sensitive
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You've previously used lower-strength retinol
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You want to introduce vitamin A for fine lines, texture or uneven tone
If you've never used vitamin A and know your skin is reactive, Crystal Retinal 1 may still be the more cautious option.
Crystal Retinal 1 vs 3: which should a beginner choose?
This is one of the most common questions around the range.
The answer depends on your skin rather than your age.
If you have relatively resilient skin and no history of sensitivity to active ingredients, Crystal Retinal 3 may be a reasonable beginner option.
If your skin is sensitive, reactive or you've struggled with retinoids previously, starting with Crystal Retinal 1 gives you a gentler introduction.
There is no prize for starting higher.
Medik8 Crystal Retinal 6 – Regular
0.06% retinal
Crystal Retinal 6 is the next step for people who have already established good tolerance to retinal.
It may suit someone who:
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Has already used Crystal Retinal 3 consistently
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Regularly uses vitamin A
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Wants to progress to a stronger retinal concentration
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Is targeting visible signs of ageing, texture or uneven tone
Medik8 recommends using at least one full tube of your existing Crystal Retinal strength before progressing to the next level.
Crystal Retinal 3 vs 6: when should you move up?
Don't move from Crystal Retinal 3 to 6 simply because you've reached a certain number of weeks.
Consider how your skin is responding.
If you're using Crystal Retinal 3 consistently without persistent dryness, irritation or sensitivity and have completed a full tube, you may consider moving to Crystal Retinal 6.
However, if Crystal Retinal 3 is working well for your skin, there is no requirement to increase the strength.
A skincare routine isn't a race to the highest percentage.
Medik8 Crystal Retinal 10 – Advanced
0.1% retinal
Crystal Retinal 10 is designed for more advanced vitamin A users.
This isn't generally where I would suggest someone completely new to retinoids begins.
Instead, it may be appropriate for someone who has already established tolerance to lower retinal strengths and wants to continue progressing through Medik8's ladder.
Crystal Retinal 6 vs 10: which should you choose?
If you're tolerating Crystal Retinal 6 well but haven't completed a full tube, I'd generally resist the temptation to rush ahead.
If you've used Crystal Retinal 6 consistently, your skin is comfortable and you want to progress, Crystal Retinal 10 represents the next step.
Again, stronger doesn't automatically mean better.
The objective is to find a strength you can use consistently without repeatedly disrupting your skin barrier.
Medik8 Crystal Retinal 20 – Experienced
0.2% retinal
Crystal Retinal 20 sits towards the top of the Crystal Retinal ladder and is intended for experienced vitamin A users.
This strength is not designed as a starting point simply because somebody wants faster results.
It is better considered after establishing good tolerance to the preceding Crystal Retinal strengths.
Medik8 Crystal Retinal 24 – Expert
0.24% retinal
Crystal Retinal 24 is currently the highest-strength Crystal Retinal face serum within the range.
It is positioned for expert vitamin A users who have progressed through the lower Crystal Retinal strengths and have established excellent tolerance.
For most people beginning their retinal journey, Crystal Retinal 24 shouldn't be the goal.
Your goal should be healthy skin and a routine you can maintain.
Do I eventually need Crystal Retinal 20 or 24?
No.
This is something I think is particularly important to understand.
You don't graduate from a lower retinal strength simply because you've used it for a certain period.
If your current Crystal Retinal is delivering results and your skin is happy, you may decide to remain at that strength.
Higher concentrations may also carry a greater potential for irritation.
The best Crystal Retinal strength is the one appropriate for your skin, your previous vitamin A experience and your tolerance.
What does Medik8 Crystal Retinal help with?
Retinoids can form part of routines targeting several different concerns.
Fine lines and wrinkles
Retinoids are among the most established skincare ingredients used for visible signs of photoageing.
Crystal Retinal may therefore be considered as part of a wider routine targeting fine lines, uneven texture and visible ageing.
For more guidance, read our Best Skincare for Fine Lines & Wrinkles: A Doctor-Led Guide.
Acne and blemish-prone skin
Retinoids can also be useful within routines for acne-prone and congested skin.
However, acne routines need to be constructed carefully. Combining retinal with numerous acids, exfoliants and harsh treatments can result in unnecessary irritation.
Read our Retinol for Acne: A Doctor's Guide to Clearing Breakouts Safely for more information.
If you'd like to understand acne in greater detail and learn how to establish a complete routine, read our Understanding Acne & Building a Routine That Works eBook.
Explore skincare for oily and acne-prone skin →
Pigmentation and post-acne marks
Retinoids may also form part of a routine targeting uneven pigmentation and post-inflammatory hyperpigmentation.
However, retinal shouldn't be viewed as a standalone pigmentation treatment.
Daily broad-spectrum sunscreen and other appropriate pigmentation-targeting ingredients may also be required.
Read our guide to post-inflammatory hyperpigmentation →
Will Medik8 Crystal Retinal cause purging?
Some people experience an increase in blemishes when introducing a retinoid, often referred to as retinol purging or retinoid purging.
However, not every breakout after starting a new product should automatically be dismissed as a purge.
Persistent redness, burning, significant dryness or widespread irritation may instead indicate that your skin isn't tolerating the product or that you've introduced it too aggressively.
We've written a separate guide explaining this in more detail:
What Is a Retinol Purge? How Long It Lasts & How to Manage It →
How do you introduce Medik8 Crystal Retinal?
When introducing Crystal Retinal for the first time, Medik8 recommends gradually increasing application.
A simple schedule is:
Weeks 1–2: Twice per week
Weeks 3–4: Every other night
Week 5 onwards: Every night if your skin tolerates it
After cleansing in the evening, apply two pumps to the face and neck, allow the product to absorb and follow with moisturiser.
You should use sunscreen the following morning.
If your skin becomes persistently irritated, don't continue increasing frequency simply because the schedule says you should.
Your skin's response matters.
What should I use with Medik8 Crystal Retinal?
A retinal routine doesn't need to be complicated.
A simple evening routine might include:
Cleanser → Crystal Retinal → Moisturiser
And your morning routine should include appropriate broad-spectrum SPF.
If your skin is becoming dry or sensitive, consider simplifying the rest of your routine rather than adding more active ingredients.
Can I use vitamin C with Crystal Retinal?
Vitamin C and retinal can both form part of the same overall skincare routine.
A simple approach is often:
Morning: Vitamin C + SPF
Evening: Crystal Retinal + moisturiser
This separates the active ingredients and keeps the routine relatively straightforward.
Can I use acids with Medik8 Crystal Retinal?
Potentially, but this depends on your skin and the specific products involved.
If you're new to retinal, I wouldn't introduce several strong exfoliating acids at the same time.
Establish tolerance to one active first.
Over-exfoliation combined with retinoid use is an easy way to end up with a compromised skin barrier.
Can you use Medik8 Crystal Retinal around the eyes?
The skin around the eyes requires particular care.
Medik8 has developed a separate Crystal Retinal Ceramide Eye range specifically for the eye area, available in progressive strengths 3, 6 and 10.
Shop Medik8 Crystal Retinal Ceramide Eye →
How long does Medik8 Crystal Retinal take to work?
Skincare results aren't instantaneous.
Some changes in skin texture or radiance may be noticed earlier, while improvements in more established concerns such as fine lines and pigmentation require consistent use over time.
Retinoids are much better thought of as part of a long-term skincare strategy rather than a quick fix.
Can I use Medik8 Crystal Retinal during pregnancy?
Retinoids, including retinal and retinol, are generally avoided during pregnancy.
If you're pregnant, trying to conceive or unsure about whether a particular skincare ingredient is appropriate for you, discuss this with your healthcare professional.
A doctor's view: which Crystal Retinal is best?
There isn't one Crystal Retinal strength that is universally "best".
That's actually one of the things I like about the range.
It allows you to select a retinal concentration according to your previous vitamin A experience and skin tolerance, rather than assuming everyone should use the same strength.
If you're completely new to vitamin A or have sensitive skin, that may mean beginning with Crystal Retinal 1.
For many beginners with more resilient skin, Crystal Retinal 3 may be appropriate.
More experienced users can gradually progress through Crystal Retinal 6 and 10, while Crystal Retinal 20 and 24 are designed for experienced and expert users.
But don't become fixated on reaching the top of the ladder.
The best retinal isn't necessarily the strongest one. It's the one your skin tolerates consistently and that fits into a well-constructed skincare routine.
Shop Medik8 Crystal Retinal at Villa Skincare
Explore all six Medik8 Crystal Retinal strengths, from Crystal Retinal 1 for sensitive skin through to Crystal Retinal 24 for expert vitamin A users.
Or discover more professional skincare from Medik8:
Shop the Medik8 collection at Villa Skincare →
Not sure whether retinal or retinol is right for you?
Read our complete Retinal vs Retinol vs Prescription Retinoids guide →
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Written by Dr S Ahmed | Villa Skincare | Aesthetic Doctor
Updated September 2026