Litsea cubeba oil
Litsea cubeba fruit oil (may chang)
Botanical repellent oil steam-distilled from the fruit of Litsea cubeba (may chang), a tree in the laurel family native to East and Southeast Asia. It is one of the richest natural sources of citral, and that citral content is what gives the oil its mosquito-repellent activity. Human-skin evidence is still emerging, and the one controlled arm-in-cage study reporting a few hours of protection used a fixative-formulated spray, not neat oil, so the raw oil is expected to be shorter-lived.
How it works
Acts mainly as a citral-driven olfactory repellent: the volatile citral (a mix of the isomers geranial and neral) deters host-seeking mosquitoes before and at contact rather than killing them. Repellency fades as the oil evaporates from skin.
The evidence
A 2026 Scientific Reports study of a ready-to-use spray (MosShield) that pairs 6% Litsea cubeba oil with a vanillin fixative reported median complete protection times of about 225 minutes (3.75 hours) against Culex quinquefasciatus and 120 minutes (2 hours) against both Aedes aegypti and Anopheles dirus using the WHO arm-in-cage protocol, with no visible skin reactions in a 48-volunteer patch test at 96 hours. Because the oil's citral is volatile, that multi-hour protection reflects the fixative as much as the oil, and neat Litsea cubeba oil would fade faster. In the same study it was outperformed by a commercial comparator and only just met the Thai FDA 120-minute minimum for Aedes and Anopheles. Evidence is limited to a single unreplicated lab study; field confirmation is pending.
- Topical mosquito repellency of a Litsea cubeba essential oil spray against Aedes aegypti, Anopheles dirus, and Culex quinquefasciatus2026LabLimited evidence
Laboratory efficacy and short-term skin-tolerability study of a ready-to-use topical spray (MosShield) containing 6% w/w Litsea cubeba essential oil, the citral-rich oil pressed from may chang fruit. Repellency was measured with the WHO arm-in-cage complete-protection-time protocol against three medically important mosquito species, and dermal tolerability was checked with a human skin-patch test in 48 healthy volunteers.
Regulatory notes
Litsea cubeba oil is not an EPA-registered skin-applied repellent in the United States and is not on the FIFRA 25(b) minimum-risk list; in the US it is used mainly as a fragrance and flavor ingredient. The repellent products studied to date are formulated and sold outside the US. Its active constituent, citral, is a separately tracked active with its own evidence.