What is it?
An extract of the fruit of the Australian finger lime, Citrus australasica, listed on labels under its older name, Microcitrus australasica. The tree grows wild in subtropical rainforests on the Queensland–New South Wales border. Its pulp sits in small round juice vesicles, which has earned it the name caviar lime; like other citrus, the pulp’s main acid is citric acid, and it contains vitamin C. In cosmetics, citrus fruit extracts are used mainly for skin conditioning or fragrance.
Key information
- The CIR Expert Panel included finger lime fruit extract among 80 citrus fruit-derived ingredients it found safe when formulated to be non-sensitizing and non-irritating, with no more than 15 ppm of the furocoumarin 5-MOP in leave-on products.
- Finger lime pulp contains roughly 23 to 115 mg of vitamin C per 100 grams, depending on the variety.
- Finger lime is the only native Australian citrus grown commercially, on a small scale and mostly for specialty foods.
More information
Finger lime is one of six citrus species native to Australia. Botanists once placed it in a separate genus, Microcitrus, the name still used in its ingredient listing, but it is now classed in Citrus. Anecdotal reports describe Indigenous use of the fruit, and today it is grown on a small scale for specialty foods, where its popping pulp vesicles are used as a garnish in place of caviar. The juice’s volatile compounds are dominated by limonene, with linalool and citronellol among its aroma compounds.
In a final report released in 2016, the Cosmetic Ingredient Review (CIR) Expert Panel assessed 80 citrus fruit-derived ingredients, including finger lime fruit extract, which was not reported to be in use at the time. The Panel concluded that they are safe in rinse-off and leave-on products when formulated to be non-sensitizing and non-irritating, provided leave-on products contain no more than 15 ppm of 5-methoxypsoralen (5-MOP), a furocoumarin that can make skin react to sunlight. It noted that these citrus ingredients are eaten as food and asked formulators to watch combined levels of constituents such as limonene, citral and furocoumarins when several botanicals are used together.
Finger lime itself has been little studied for safety. In a 2022 screening test, zebrafish embryos kept in water containing a finger lime extract showed delayed hatching and heart effects, although even the highest concentration tested, 480 mg per liter, did not kill half of them. Results in fish embryos bathed in an extract do not translate directly to skin products, but the finding is a reminder that the fruit’s safety data are thin. On labels it appears as Microcitrus Australasica Fruit Extract.
Sources: CIR: Safety Assessment of Citrus Fruit-Derived Ingredients as Used in Cosmetics (final report, 2016); Foods (2025): Unlocking the Sublime: A Review of Native Australian Citrus Species; Antioxidants (2022): Phytochemical and Safety Evaluations of Finger Lime, Mountain Pepper, and Tamarind in Zebrafish Embryos
