'Cica', the Korean-skincare staple. Its triterpenes aid wound healing in studies; for everyday redness and barrier repair the evidence is small but encouraging.
Centella asiatica (gotu kola) is a creeping plant long used on wounds. Its active compounds are four triterpenes — madecassoside, asiaticoside, asiatic acid and madecassic acid — which in lab and animal work increase collagen production and dampen inflammation. Products list either the whole extract or one of these purified compounds.
Marketed as 'cica', it is sold for irritated, red or over-exfoliated skin and for barrier repair. Those uses fit its lab profile, but most human studies test it in combination with other actives.
Wound and scar studies (often older and small) and lab work support its activity. Cosmetic trials mostly test mixtures — a 6-month double-blind study of 5% vitamin C plus 0.1% madecassoside improved wrinkles and firmness, but can't isolate centella's share. Good placebo-controlled trials of centella alone for redness or sensitivity are lacking.
Reviews centella's triterpenes (asiaticoside, madecassoside, asiatic and madecassic acids), their pro-collagen and anti-inflammatory actions, and their use for wounds, scars, burns, photoaging, cellulite and stretch marks.
20 women with photoaged skin used 5% vitamin C with 0.1% madecassoside for 6 months in a randomized double-blind study; wrinkles, firmness, roughness and hydration improved, with a better elastic fibre network on biopsy. The design can't separate the two ingredients.