The Inkey List

Polyglutamic Acid Serum

SerumBudgetMorning or evening
Add to shelfView my shelf →
A hydration serum using polyglutamic acid, which holds even more water than hyaluronic acid, layered with HA. A lightweight, plumping hydrator that works well over or under HA; an affordable way to trial the ingredient.
The verdict

What this is good for

✓ Great forDehydrationDullnessDryness
The formulation

Ingredient stack

Each ingredient is listed in descending concentration. Above the 1% line the order is regulated — below it, brands can list in any order.

Ingredients above the dashed gold line are dosed above 1% (the regulatory threshold) — these are what the formulation is really built on. Percentages are positional estimates from INCI order unless a brand discloses them.

~50–80%Aqua
~5–25%Glycerin
~3–10%Polyglutamic Ac…
~2–6%Sodium Hyaluron…
~1.5–4%Propanediol
~1–2%Panthenol
≤ 1% each2 more ingredients below 1%
position-estimated %1% regulatory line
Hero actives

What's actually doing the work

Polyglutamic Acid
PGA Humectant
Acid
A key active in this formula. See the glossary for the full breakdown of how Polyglutamic Acid works, the evidence behind it, and how to use it.
Full glossary entry →
Hyaluronic Acid
Sodium Hyaluronate
Acid
A humectant that binds water in the upper skin layers for immediate plumping and hydration. Multi-weight forms reach different depths. Apply to damp skin and seal with moisturiser, especially in dry climates.
Full glossary entry →
When to use

Routine placement

Morning or evening
Cheaper alternatives

Looking for a dupe?

The closest active-matched alternative is the Haruharu Wonder Black Rice Hyaluronic Serum (70% active overlap). We found 6 options that share this product’s hero actives.

Dupe guide
See all serum dupes for this product
Ranked by ingredient overlap, with an honest note on what’s different in each.
Related products

Similar on the shelf

The Inkey List
Retinol Anti-Aging Serum
Serum
The Inkey List
Niacinamide Serum
Serum
The Inkey List
Hyaluronic Acid Serum
Serum
Anua
Heartleaf Quercetinol Pore-Deep Cleansing Serum
Serum
Next steps

Put this in context

Decode another product
Check a different formula
Paste any INCI list and get the same ingredient-by-ingredient breakdown.
Score your whole shelf
Run a Stack Audit
See how this product fits alongside everything else you’re using — conflicts, gaps, overlap.

Skin Stacker is independent and receives no payment from any brand. Ingredient analysis is based on publicly disclosed INCI lists and the peer-reviewed literature. Percentages are positional estimates from INCI order unless a brand discloses them. Formulations change — always re-check the label on your specific batch before using.