Malabar kino, an Ayurvedic tree resin

Malabar kino (also called Indian kino, or Pterocarpus marsupium) is the deep red-brown resin that bleeds from the Pterocarpus tree when its bark is cut. It has a longer record in Ayurvedic practice than in cosmetics, and its chemistry is dominated by condensed tannins, with pterostilbene and marsupin as the compounds that draw most of the modern laboratory interest.

Two millennia of Ayurvedic record

Malabar kino appears in the Sanskrit medical literature, including the Charaka Samhita and the Sushruta Samhita, which describe specific preparations of the resin, wood and bark. The tree is Bijasar in Sanskrit and Vijaysar in Hindi. What follows is a description of traditional practice, not a claim about what the ingredient does.

• Traditionally used for blood-sugar management. This is the primary historical application described in the texts, using wood, bark and resin.
• "Bijasar water." Pieces of bark are traditionally soaked overnight; the water turns red and is drunk. It is still sold commercially as Pterocarpus marsupium water.
• Topical preparations described for skin. Traditional practice applied the resin to cuts, abscesses and conditions the texts group as "blood disorders" affecting the skin.
• Concentrated resin pastes. Described in traditional wound care, applied to cuts and ulcers.

Cosmetic use is far more recent. Western and Asian premium skincare brands picked the material up over roughly the past fifteen to twenty years, as laboratory work began describing the chemistry behind the traditional preparations.

A wound resin from an Indian hardwood

Pterocarpus marsupium is a deciduous tree of peninsular India, Sri Lanka, Nepal and parts of Southeast Asia, reaching 25 to 30 metres. When the bark is cut or naturally wounded, a thick resin flows out and hardens into the dark red-brown solid called kino.

The word itself travelled. "Kino" comes from a West African term for similar tree resins, and European botanists applied it to comparable exudates elsewhere, including several eucalyptus species, which are chemically distinct from the Indian material.

Harvesting follows the tree's own defence: small slashes are cut into the bark, the resin is collected over weeks as it exudes and hardens, and the dried resin is then powdered or extracted. Done this way it does not damage the tree and the resin replenishes. Wild populations are nonetheless under pressure from habitat loss, so sourcing certification matters.

The tannin fraction and its astringent behaviour

The bulk of malabar kino is condensed tannins, the proanthocyanidin class, alongside phenolic acids such as gallic and ellagic acid. Tannins precipitate proteins. On skin that translates into a thin film across the upper stratum corneum and the tightening sensation cosmetic chemists call astringency, which is a physical effect on the surface rather than an action on anything below it.

The same tannin fraction is what gets screened in laboratory antimicrobial work, mostly against gram-positive bacteria and some fungi.

Tannins also carry colour. Concentrated resin, in the strength used for traditional preparations, can temporarily tint skin and fabric. Cosmetic formulations use low enough concentrations that this does not happen.

Pterostilbene, marsupin and the rest of the profile

• Pterostilbene, a dimethoxy methylated analogue of resveratrol. Methylation makes it more bioavailable than resveratrol itself, which absorbs poorly by mouth and topically. It is a strong antioxidant and has been studied for its behaviour at the Wnt and beta-catenin signalling pathway.
• Marsupin, a pterocarpan compound examined in inflammation and blood-glucose research.
• Pterosupin, a chalcone glucoside with antioxidant properties.
• Liquiritigenin and related flavonoids, shared with several other plant sources.

Pterostilbene is the compound that gets the attention, and it is worth being precise about why: it is among the better-studied stilbene antioxidants, which is a statement about the research literature rather than about a result on anyone's face.

The published record and its edges

Two strands of work sit behind the cosmetic use. One examines extracts of the species itself; the other looks at kino resins more broadly.

The edges of that record are worth stating plainly. Malabar kino does not inhibit tyrosinase directly the way licorice glabridin does, so any pigmentation-adjacent research on it runs through the inflammatory pathway instead. The cosmetic evidence base is thinner than turmeric's or licorice's: a long traditional record plus modern mechanism studies, with few dermatology-specific clinical trials. Nothing here happens overnight, and formulation matters more than any single ingredient in it.

On safety: topical use at cosmetic concentrations is well tolerated, with a long traditional record and no significant modern issues reported. Oral preparations are a different matter, because Pterocarpus marsupium can affect blood glucose and should not be combined with diabetes medication without medical supervision. Topical use carries no documented systemic absorption at medically meaningful levels. Allergic reactions are rare; patch test if you react to legume-family (Fabaceae) plants. Traditional guidance on use during pregnancy is mixed and concerns oral preparations; for topical cosmetics there are no documented concerns, but confirm with your clinician.

Malabar kino in WhollyKaw's Night Toning Cream

WhollyKaw uses malabar kino in one product: Night Toning Cream, where it sits alongside turmeric and licorice. The three come from different chemistry, which is the reason for combining them rather than picking one.

Related ingredient reading: turmeric, licorice root and vitamin C.