Alaria Esculenta Extract

This ingredient comes from winged kelp; it's an edible brown seaweed found on exposed rocky Atlantic shores.

In cosmetics, it has skin protecting and hair conditioning properties.

Lab testing has shown it to be an impressive antioxidant: out of 3 Icelandic seaweeds, Alaria had the most phenolics, flavonoids, and strongest antioxidant capacity. It also blocked the enzymes that break down collagen, elastin, hyaluronic acid, and the enzyme that drives pigment creation.

Cell studies found it could lower progerin production in aged skin cells (with no effect in cells from young donors). Progerin is a protein that weakens the cell nucleus and drives both premature aging and normal aging processes

Just keep in mind these results are all from test tube and cell studies and there are currently no human trials on the extract itself.

Safety-wise, this one has a solid record. Human sensitization tests at 0.5 to 2.5% and under 5% all came back negative, and brown algae ingredients aren't restricted in the EU.

Acne

You'll see algae listed as a 5/5 on a lot of pore-clogging charts and that number doesn't come from anywhere; it's not in the original rabbit-ear studies that most comedogenic ratings trace back to.

The reasoning behind the reputation is that seaweed is high in iodine and iodine can trigger acne-like breakouts when eaten. This traces back to a 1976 letter in Archives of Dermatology describing two women whose breakouts cleared after they stopped taking high-dose kelp supplements orally.

And the reaction of these two women wasn't clogged pores at all: it was an iodine-triggered pustular rash. Later research found normal dietary iodine doesn't meaningfully affect acne either and nobody has shown topical algae delivers enough iodine to matter.

What we do have is dozens of brown and red algae ingredients found to be non-irritating and non-sensitizing, and a handful of studies that found algae compounds may actually help acne.

However, plenty of people do report breaking out from algae-containing products. Skin is individual and it's worth avoiding if yours has reacted to algae before.