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Macrocystis pyrifera is the largest alga on the planet: it forms underwater forests that can grow more than thirty meters tall and half a meter in a day. In cosmetics, its extract is almost always used alongside hyaluronic acid, for a specific reason.
Article written by Elisa Avalle, founder of LeLang Skin Care and dermocosmetics specialist. Cover image generated with the support of artificial intelligence.
What it is and what it contains
It is a brown alga found in the cold waters of the Pacific. It is rich in sulfated polysaccharides, particularly alginates and fucoidans: molecules that provide structural support and protect the plant from dehydration during low tide.
These are exactly the properties that make it useful in cosmetics. An organism that needs to retain water when its environment draws it away has developed highly efficient molecules for doing so.
On the label, the extract appears as Macrocystis Pyrifera Extract, often as part of a complex that already includes water, glycerin, and hyaluronic acid.
What it does for the skin
Its main action is film-forming and hydrating: the polysaccharides form a film on the surface that slows water evaporation and leaves the skin feeling soft and smooth.
Fucoidans also provide an antioxidant effect, along with marine trace elements—magnesium, iodine, and zinc—which the alga concentrates from seawater.
The reason it is almost always found alongside hyaluronic acid is that their effects complement each other: hyaluronic acid binds water, while the alga's polysaccharides form a film that keeps that water from escaping. One replenishes, the other retains.
As with all film-forming actives, the effect is superficial and reversible: it lasts as long as the product remains on the skin and requires consistent use. It does not produce structural changes.
Where to find it in LeLang formulas
It is found in the intensive moisturizing cream and multi-peptide serum, in both cases alongside different forms of hyaluronic acid. The choice of an alga from cold waters is no coincidence: these algae have the highest concentration of polysaccharides.
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Frequently asked questions about Macrocystis alga
Are all algae in cosmetics the same?
No. Brown, red, and green algae have very different compositions: brown algae are rich in alginates and fucoidans, red algae in carrageenans, and green algae in other polysaccharides. Their properties and uses in formulas differ.
Should people with thyroid problems avoid cosmetics containing algae?
Algae concentrate iodine, but absorption through the skin from a cosmetic is minimal and not comparable to taking algae-based supplements. If you have a thyroid condition, you should still ask your doctor.
Is it sustainable?
Macrocystis grows very quickly and is harvested using techniques that leave the base of the plant intact, allowing it to regrow. It is among the most renewable marine biomass sources.
Is it suitable for oily skin?
Yes. The extract is water-soluble, and the film it forms is neither greasy nor occlusive.
Does it have anti-aging effects?
It helps the skin's surface look smoother through hydration and provides antioxidants. It does not act on the skin's supporting structures, and formulas that suggest otherwise promise more than the ingredient can deliver.
