What is Limonene?

Daniel Judd BSc MBiol


What is limonene?

Limonene is a natural product found in the rinds of lemons and other citrus fruits, which explains the name. It can be produced from these fruits through a process called steam distillation where steam is used to evaporate the limonene out of the rind. Once purified, it is a clear liquid with a sweet citrus smell. This citrus smell makes it a popular fragrance in scented products of all varieties from lipsticks to bubble bath products.

Outside of cosmetic products, limonene also works as solvent in cleaning products that helps dissolve grease and as a natural insecticide for protecting plants from pests.


How does it work?

As limonene has a strong citrus smell, it can give that fragrance to products that would otherwise be unscented. It can also be used to mask any ingredients that have a less pleasant smell. It’s similarly used in some food and medicine to cover up unpleasant tastes.

As a solvent, it is good at dissolving chemicals that don’t like dissolving in water. Oily and greasy substances repel water and can’t dissolve in it, but don’t repel limonene. While there is use for ingredients that dissolve oil in skin care products like cleansers and soaps, other ingredients are typically used.



What are the side effects?

Limonene is a known irritant to the skin and eyes and as such can trigger bad reactions like red, blistered, dry or cracked skin seen in contact dermatitis. It’s also possible to experience an allergic reaction to it.

As it is usually only used for fragrance it may be worth looking for unscented products instead if you do experience any side effects mentioned above.

Interactions with other medicines:

There are no known interactions between limonene and medicines.


Other names for limonene

(+)-(R)-4-isopropenyl-1-methylcyclohexene; (+)-limonene; (-)-limonene; (4R)-1-methyl-4-(1-methylethenyl)cyclohexene; (4S)-1-methyl-4-isopropenylcyclohex-1-ene; (D)-limonene; (R)-(+)-limonene; (R)-4-isopropenyl-1-methylcyclohexene; 1-methyl-4-(1-methylethenyl)cyclohexene; 4-mentha-1,8-diene; AISA 5203-L (+)limonene; cyclohexene, 1-methyl-4-(1-methylethenyl)-, (4R)-; d-limonene; dipentene; limonene; limonene, (+)-; limonene, (+-)-isomer; limonene, (R)-isomer; limonene, (S)-isomer