Side-by-side comparison

Medik8 Crystal Retinal 6 vs The Inkey List Niacinamide Serum

Both are serums, but their key treatment ingredients don't overlap: Medik8 Crystal Retinal 6 is built around Retinaldehyde, while The Inkey List Niacinamide Serum is built around Niacinamide.

1Shared hero active
Medik8
Crystal Retinal 6
SerumLuxuryEvening only
Fine LinesPhotoaging PreventionRough Texture

A stabilised retinaldehyde serum (0.06%) with hyaluronic acid and vitamin E, sitting between retinol and prescription tretinoin in strength. Faster-acting than retinol with good tolerability; part of a tiered ladder you climb gradually.

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The Inkey List
Niacinamide Serum
SerumBudgetMorning or evening
OilinessCongestionDark Spots

A 10% niacinamide serum with added hyaluronic acid for oil control and blemish support. A clean, affordable single-active option; broadly comparable to other 10% niacinamide serums with a slightly more hydrating base.

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The verdict

Which should you choose?

These do different jobs. Medik8 Crystal Retinal 6 relies on Retinaldehyde, while The Inkey List Niacinamide Serum relies on Niacinamide. Medik8 Crystal Retinal 6 is the better fit for fine lines, preventing sun damage and rough texture; The Inkey List Niacinamide Serum for oiliness, congestion and dark spots. On price, The Inkey List Niacinamide Serum is the less expensive option (Budget versus Luxury). Medik8 Crystal Retinal 6 is flagged evening only; The Inkey List Niacinamide Serum is flagged morning or evening.

The overlap

What they share

This hero active appears in both formulas:

Hyaluronic Acid
The formulation

Ingredient stacks, side by side

Medik8 Crystal Retinal 6 — top of the list

  • Aqua~50–80%
  • Glycerin~5–25%
  • Caprylic/Capric…~3–10%
  • Dimethicone~2–6%
  • Retinal~1.5–4%

The Inkey List Niacinamide Serum — top of the list

  • Aqua~50–80%
  • Niacinamide~5–25%
  • Glycerin~3–10%
  • Sodium Hyaluron…~2–6%
  • Pentylene Glycol~1.5–4%

● marks ingredients that appear near the top of both lists. Percentages are positional estimates from INCI order, not disclosed doses.

At a glance

The specs

Medik8 Crystal Retinal 6The Inkey List Niacinamide Serum
CategorySerumSerum
Price tierLuxuryBudget
Best forFine Lines, Photoaging Prevention, Rough TextureOiliness, Congestion, Dark Spots
Usage notesEvening onlyMorning or evening
Shared hero activesHyaluronic Acid
Questions

Common questions

Is the Medik8 Crystal Retinal 6 or The Inkey List Niacinamide Serum better?
They aren't trying to do the same thing, so the better one is whichever matches your goal: Medik8 Crystal Retinal 6 for fine lines, preventing sun damage and rough texture; The Inkey List Niacinamide Serum for oiliness, congestion and dark spots.
What's the difference between the Medik8 Crystal Retinal 6 and The Inkey List Niacinamide Serum?
Medik8 Crystal Retinal 6's hero actives are Retinaldehyde, Hyaluronic Acid and Vitamin E. The Inkey List Niacinamide Serum's are Niacinamide and Hyaluronic Acid. They also sit in different price tiers (Luxury versus Budget).
Are the Medik8 Crystal Retinal 6 and The Inkey List Niacinamide Serum dupes for each other?
No. Their key active ingredients don't overlap (Retinaldehyde in Medik8 Crystal Retinal 6; Niacinamide in The Inkey List Niacinamide Serum), so swapping one for the other changes what your routine does.
Can I use the Medik8 Crystal Retinal 6 and The Inkey List Niacinamide Serum together?
Usually, yes. Apply the thinner texture first, then the thicker one, and patch-test when introducing anything new.
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2 shared hero actives

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