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The Cast Index

Medik8 · United Kingdom

Crystal Retinal

Skin prep · Retinal night serum · Serum

An evening treatment with a clear strength ladder — kept to night routines so daytime base sits on settled skin.

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The desk verdict

The clearest retinal ladder in the UK: six numbered strengths from 0.01% to 0.24% retinaldehyde, each 30ml, from £45. Start low, follow Medik8’s build-up schedule and finish a tube before moving up. It is not strictly fragrance-free.

Skip this if you are pregnant or breastfeeding, want a strictly fragrance-free formula, or want a single low-cost bottle rather than a strength system.

The short version

The short version of this review

Medik8 Crystal Retinal is a retinaldehyde night serum sold in six strengths, from Crystal Retinal 1 (0.01%) to Crystal Retinal 24 (0.24%), each 30ml and priced £45–£114 on Medik8 UK on 25 September 2026. Medik8 directs evening use, a gradual build-up and next-morning sunscreen, and advises avoiding vitamin A in pregnancy.

Product information reviewed 2026-09-25.

01 / The basics

What is Crystal Retinal?

Medik8 sells Crystal Retinal in six strengths from 0.01% to 0.24% retinaldehyde (Crystal Retinal 1 to 24), each 30ml, with hyaluronic acid and vitamin E; the brand directs evening use, a gradual build-up, sunscreen the next morning and avoiding vitamin A in pregnancy and breastfeeding.

Best for
A graduated retinal routine, from first use to expert strength

02 / Review

What is in Crystal Retinal?

Crystal Retinal uses retinaldehyde (retinal), a retinoid one step closer to retinoic acid than retinol, in six numbered strengths from 0.01% to 0.24%. Medik8 pairs it with hyaluronic acid and vitamin E; squalane and two vitamin C derivatives also appear in the ingredient list.

The numbered system is the point: it lets a first-time user start low and move up only after finishing a tube. Crystal Retinal 24, added in 2024, is intended only for users who have completed Crystal Retinal 20.

03 / Review

Who is Crystal Retinal best for?

Someone new to retinoids who wants a clear route from a low starting strength to an advanced one, and experienced users who prefer retinal to retinol.

04 / Review

What should you check before buying?

Start with the lowest strength if you are new to vitamin A, and follow the brand’s build-up schedule. It is not fragrance-free in the strict sense: coumarin, tonka bean and vanilla extracts appear in the ingredient list. Medik8 advises avoiding vitamin A during pregnancy and breastfeeding; speak to a GP or midwife.

05 / How to use it

How should you use Crystal Retinal?

  1. 01Apply two pumps to face and neck in the evening, after cleansing
  2. 02Start twice a week for two weeks, then every other night for two weeks, then nightly, as Medik8 directs
  3. 03Finish a tube before moving up a strength
  4. 04Wear sunscreen the next morning

06 / Quick facts

What should you know before choosing Crystal Retinal?

  • —Six strengths, each 30ml: Crystal Retinal 1 (0.01%), 3 (0.03%), 6 (0.06%), 10 (0.1%), 20 (0.2%) and 24 (0.24%) retinaldehyde
  • —From £45 (Crystal Retinal 1) to £114 (Crystal Retinal 24) on Medik8 UK, 25 September 2026
  • —Night serum with hyaluronic acid, vitamin E and glycerin; Vegan Society certified
  • —“No artificial fragrance”, but coumarin, tonka bean and vanilla extracts are on the ingredient list
  • —Build-up: twice a week for two weeks, every other night for two weeks, then nightly; one tube before moving up a strength
  • —Sunscreen the next morning; Medik8 advises avoiding vitamin A in pregnancy and breastfeeding

Further reading on The Cast Index

Facts on this page are drawn from the brand’s own product information and named, reputable press coverage, summarised in our own words. Inclusion in the Beauty Desk edit is editorial and independent of any commercial relationship. Last reviewed 2026-09-25. Corrections: desk@thecastindex.com.

FAQ

Crystal Retinal, answered

What is Crystal Retinal by Medik8?

Crystal Retinal is a retinal night serum from Medik8, formulated for a graduated retinal routine, from first use to expert strength. Medik8 sells Crystal Retinal in six strengths from 0.01% to 0.24% retinaldehyde (Crystal Retinal 1 to 24), each 30ml, with hyaluronic acid and vitamin E; the brand directs evening use, a gradual build-up, sunscreen the next morning and avoiding vitamin A in pregnancy and breastfeeding.

Which Medik8 Crystal Retinal strength should I start with?

The range runs upwards from Crystal Retinal 1, and Medik8 advises finishing a tube before moving up. New retinoid users start at a low strength; Crystal Retinal 24 is only for users who have completed Crystal Retinal 20.

Can I use Crystal Retinal while pregnant?

Medik8 generally recommends avoiding vitamin A while pregnant or breastfeeding and suggests speaking to your GP or midwife.

Is retinal stronger than retinol?

Retinal is one step closer to retinoic acid, the form skin uses, so products use lower percentages. Compare strengths within the same retinoid rather than across retinal and retinol.

Also reviewed by the desk

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