What it is
This extract is derived from the galls that form on Rhus semialata (Chinese sumac), which are exceptionally high in gallotannins and gallic acid. In cosmetic formulations it functions as an astringent and skin-conditioning agent, and it contributes antioxidant activity associated with its high polyphenol content. It is typically included at low levels as a supporting botanical rather than a primary functional ingredient.
Safety & warnings
Tannin-rich gall extracts are generally well tolerated at the low levels used in cosmetics. Because they are astringent, they may feel tightening on very dry or sensitive skin, and as with most botanical extracts there is a low background potential for irritation or sensitization in predisposed individuals.
Origin & sourcing
Natural, plant-derived. It is extracted from the abnormal growths (galls) that develop on the Chinese sumac tree, largely in East Asia, in response to aphid activity; the galls are harvested and processed to obtain the tannin-rich extract.
History
Galls of Rhus species, known traditionally as gallnut or Galla Rhois, have a long history of use in East Asian traditional medicine and as a tanning and dyeing material owing to their very high tannin content.
Questions everyone asks
What is Rhus semialata gall extract made from?
It is made from the galls (growths) that form on the Chinese sumac plant, which are rich in tannins and processed into a skin-conditioning extract.
Is it a UV filter?
No. It is a botanical conditioning and astringent ingredient and does not provide sun protection on its own; it supports the rest of the formula.