Top 10 Retinaldehyde Questions Answered

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Top 10 Retinaldehyde Questions Answered

1. What is retinaldehyde?

Retinaldehyde is a revolutionary form of vitamin A. It is proven to be 11x faster-acting than the classic form of vitamin A, retinol[1], yet is a notoriously unstable molecule therefore potent retinaldehyde is rarely found in skincare. Medik8 is the market-leader in stabilised retinaldehyde (retinal) vitamin A skincare innovations.

2. What does retinaldehyde do?

Proven to work up to 11 times faster than the classic form of vitamin A retinol[1], retinaldehyde targets the appearance of fine lines and wrinkles, hyperpigmentation and uneven skin texture. Retinaldehyde also has unique antibacterial properties, unlike other forms of vitamin A, which mean it is able to target the appearances of blemishes and clarify the complexion.

3. What Medik8 products contain retinaldehyde?

Retinaldehyde is the star of our cult-favourite Crystal Retinal®, available in a series of progressive strengths from Crystal Retinal 1 (0.01% retinal) all the way to Crystal Retinal 20 (0.2% retinal). 

Retinaldehyde is also found in r-Retinoate Intense, our most powerful anti-ageing product, twinned with Medik8-exclusive vitamin A molecule retinyl retinoate for ultimate youth-renewing results.

4. When will I see results from retinaldehyde?

The ground-breaking Crystal Retinal formula works fast to deliver the clinically proven benefits that sets Medik8 above the rest. 

With just one tube*

- The appearance of wrinkles and hyperpigmentation is reduced by 20%

- Skin firmness is increased by 11%

- 100% agree skin appears brighter

- 100% agree skin appears healthier

- 100% agree Crystal Retinal is gentle

*Proven via independent clinical study on Crystal Retinal 6. Tested on 33 participants over 12 weeks.

5. Which is more effective: retinaldehyde vs retinol?

In order to have an effect in the skin, any form of vitamin A must be converted along the ‘vitamin A pathway’ to reach its biologically active form called retinoic acid. So whichever form you apply, it ultimately needs to reach retinoic acid before any of the benefits can happen. 


There are four steps to the conversion into retinoic acid; beginning with retinyl esters - the weakest form of vitamin A that we don’t use at Medik8, into retinol, then to retinaldehyde, and then finally retinoic acid. 

Retinol is two conversion steps away from retinoic acid, retinaldehyde however requires just one conversion step to retinoic acid. The fewer conversions required, the more benefits delivered to the skin. In fact, retinal has been scientifically proven to act on the skin 11x faster than retinol[1], with no added irritation potential.

The retinaldehyde molecule also has unique antibacterial properties, making it the perfect vitamin A choice for blemish-prone skins.

6. How does retinaldehyde compare to prescription-strength vitamin A?

Retinaldehyde has been proven to be almost as powerful as retinoic acid, the active form of vitamin A that is only available in prescription-strength products,[2] but with much less irritation potential.  Retinaldehyde also shows direct, powerful antibacterial properties and therefore has the ability to directly, and rapidly, target blemish-causing bacteria, helping to reduce the appearance of blemishes without drying out the skin, as well as addressing ageing concerns.

Prescription-strength vitamin A products are usually limited to short-term use, due to side effects such as skin redness, irritation and dryness. Every aspect of Medik8’s go-to retinaldehyde serum Crystal Retinal is designed for long-term use, with the creamy hydrating formula available in 5 progressive strengths for the option to intensify results over time.

7. When should I use retinaldehyde in my regime?

When to apply your retinaldehyde  in your routine depends on which type of product you are using.

Medik8’s retinaldehyde infused Crystal Retinal is an emulsion-based serum, therefore should be applied after cleansing, direct acids/toners, water-based serums, oil-based serums and before moisturiser.

If you are new to vitamin A, Medik8 recommend that retinol or retinal application is phased in gradually at night. This allows the skin to get used to the ingredient and helps guarantee a really comfortable vitamin A experience.

We advise that if you are totally new to vitamin A to start with Crystal Retinal 3. Use twice a week for the first 2 weeks, then once every other night for a further 2 weeks, and then nightly application. Once your skin has built up a tolerance to retinal, you can then move on to a higher strength of Crystal Retinal if intensified results are desired. 

8. What age should I start using retinaldehyde?

You can start using retinaldehyde as early as your 20s. For those in their 20s looking to prevent signs of ageing, Crystal Retinal 3 is an ideal place to start. Featuring next-generation form of vitamin A retinal which has antibacterial properties, Crystal Retinal promotes a visibly clarified complexion while addressing the appearance of fine lines and wrinkles.

9. Can I use retinaldehyde on sensitive skin?

Retinaldehyde is suitable for all skin types but it can take some time getting used to, especially if you have sensitive skin. Our Crystal Retinal ladder offers a beginner strength product especially for sensitive skin types; Crystal Retinal 1. It is ideal for those looking to incorporate a gentle vitamin A into their skincare routine without compromising on results.

10. Which retinaldehyde product is more powerful: Crystal Retinal vs r-Retinoate Intense?

Crystal Retinal and r-Retinoate often get compared to each other as they both harness the next-generation powers of retinaldehyde. The main difference between the two is the product type.

r-Retinoate Intense is Medik8’s most powerful product, ever. More than a single-active vitamin A serum, r-Retinoate Intense contains both retinyl retinoate and retinaldehyde. It is a sumptuous all-in-one night cream that also features ceramides, hyaluronic acid, squalane and anti-ageing peptides. Therefore r-Retinoate Intense actually can replace multiple steps in your evening routine, such as Advanced Night Restore, Crystal Retinal, Liquid Peptides and Hydr8 B5, as their benefits are found in r-Retinoate Intense.


Crystal Retinal is for those that are driven by results, looking for a targeted powerful serum-cream that is part of a multi-step skincare routine. It is our ‘everyone’ vitamin A product; perfect for those new to skincare and vitamin A, those wanting to target blemishes due to the antibacterial action, and of course, those already on the Crystal Retinal ladder.


[1] G. Siegenthaler et al., Retinol and retinal metabolism, Biochemical Journal, 1990, 268, pp 371-378

[2] P. Creidi P et al., Profilometric evaluation of photodamage after topical retinaldehyde and retinoic acid treatment, J Am Acad Dermatol, 1998, 39, pp 960–965

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