Microcitrus Australis Fruit Extract

Microcitrus australis (finger lime) fruit extract is typically used at low percentages as an antioxidant/brightening botanical, but citrus-derived extracts can contain naturally occurring acids and aromatic constituents that increase stinging risk on compromised barriers. Clinical patch-test data for this specific extract is limited, and in eczema-prone or post-procedure skin I see a non-trivial rate of burning or redness with citrus botanicals even when marketed as gentle. Given the uncertainty plus known citrus reactivity in sensitive populations, I rate it as a moderate irritant where patch testing is prudent. Safety Notes: Microcitrus australis (Australian finger lime) fruit extract is typically used as a botanical antioxidant/AHA-adjacent “brightening” support ingredient, and in mass-market leave-on serums/creams it is often present at very low levels (~0.001–0.05%) consistent with label-claim botanical extract usage. Mid-range usage in consumer toners/essences and exfoliating/brightening products commonly falls around ~0.1–1% depending on supplier activity/solvent system. The upper end (~2–5%) is seen in high-claim natural/“superfruit” leave-on masks/serums where the extract is a primary feature; higher levels are uncommon due to cost, odor/color, and stability/irritation considerations rather than a specific regulatory cap (no EU/FDA maximum specifically set for this extract as such).