Side-by-side comparison

Medik8 Crystal Retinal 6 vs The Inkey List Niacinamide Serum

Both are serums. They share a 66% active-ingredient overlap, so the real decision is about price, texture and the supporting ingredients. Here's the side-by-side.

66%Active overlap
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.

Full analysis →Find dupes →
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.

Full analysis →Find dupes →
The verdict

Which should you choose?

On price, the The Inkey List Niacinamide Serum sits in the Budget tier versus Luxury for the Medik8 — so it's the more budget-led pick if the overlap is what you're after. On how you'd use them, the Medik8 is flagged Evening only while the The Inkey List is flagged Morning or evening. The Medik8 leans toward Fine Lines, Photoaging Prevention, Rough Texture. The The Inkey List leans toward Congestion, Dark Spots, Oiliness.

The overlap

What they share

At 66% active overlap, these are the ingredients doing comparable work in both formulas:

Hyaluronic Acid
The formulation

Ingredient stacks, side by side

Medik8 — top of the list

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

The Inkey List — 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

Medik8The Inkey List
CategorySerumSerum
Price tierLuxuryBudget
Best forFine Lines, Photoaging Prevention, Rough TextureOiliness, Congestion, Dark Spots
Usage notesEvening onlyMorning or evening
Active overlap66% — Hyaluronic Acid
Questions

Common questions

Is the Medik8 Crystal Retinal 6 or the The Inkey List Niacinamide Serum better?
Neither is universally better — they share 66% active-ingredient overlap, so for the actives that drive results they're close. The The Inkey List Niacinamide Serum is the more budget-friendly option, while the other may differ on texture, finish and supporting ingredients. Pick based on your skin's priorities rather than a single 'winner'.
What's the difference between the Medik8 Crystal Retinal 6 and the The Inkey List Niacinamide Serum?
Both are serums that share Hyaluronic Acid. Where they differ: they sit in different price tiers (Luxury vs Budget); the Medik8 is Evening only; the The Inkey List is Morning or evening; the Medik8 targets Fine Lines, Photoaging Prevention; the The Inkey List targets Congestion, Dark Spots.
Are the Medik8 Crystal Retinal 6 and The Inkey List Niacinamide Serum dupes for each other?
They share 66% active-ingredient overlap based on published INCI lists, so one can stand in for the other on the actives that matter — chiefly Hyaluronic Acid. A dupe matches the hero actives, not the full sensory experience, so expect differences in texture, fragrance and exact concentrations.
Can I use the Medik8 Crystal Retinal 6 and The Inkey List Niacinamide Serum together?
They both fill the serum slot in a routine, so you'd normally pick one rather than layer both. If you want to use both, treat one as your daytime option and the other for evening, and patch-test when introducing anything new.
Keep comparing

Related comparisons

Estée Lauder Advanced Night Repair Synchronized Multi-Recovery Complex vs Medik8 Crystal Retinal 6
77% overlapMedik8 Crystal Retinal 6 vs Vichy Minéral 89 Hyaluronic Acid Booster
70% overlapHaruharu Wonder Black Rice Hyaluronic Serum vs Medik8 Crystal Retinal 6
66% overlapMedik8 Crystal Retinal 6 vs Neutrogena Rapid Wrinkle Repair Retinol Oil
66% overlapMedik8 Crystal Retinal 6 vs The Inkey List Hyaluronic Acid Serum
66% overlapGlow Recipe Watermelon Glow Niacinamide Dew Drops vs The Inkey List Niacinamide Serum
99% overlap

Want a deeper, personalised read? Drop both products into the live comparison tool for an ingredient-by-ingredient breakdown tuned to your skin profile.

Compare these yourself →