Can castor oil go bad?
In this short article, we will answer the query, “Can castor oil go bad?” We will also briefly discuss the shelf life of castor oil and the best practices for storing it.
Can castor oil go bad?
Yes, castor oil does go bad. Like other oils, the main degradation pathway is fat oxidation, which leads to rancidity.
Castor oil can easily oxidize because unsaturated fat predominates in its composition, corresponding to more than 90% of the total fat .
Studies have revealed that unsaturated fat can easily undergo oxidation when exposed to air .
Fat oxidation is a complex chemical reaction that occurs when fats come into contact with oxygen, leading to the breakdown of the fats and the formation of unwanted compounds.
Fat oxidation gives rise to the appearance of off-flavors and off-odors (rancidity), nutrient losses, and toxic compounds .
Light and heat boost oxidation , enhancing the production of these undesirable outcomes.
What is the shelf life of castor oil?
An unopened bottle of castor oil has a shelf life of up to one year when properly stored .
Actually, castor oil has a best-before date rather than an expiration date. This means that the oil peaks its finest quality by the date printed on labels. Past that date, it may be chemically degraded, especially if incorrectly stored .
After being open, the shelf life will depend on the handling practices. The reason is that when you open a bottle of castor oil, it gets exposed to air, which leads to a quality drop over time.
If you store the oil bottle fastened, away from excessive heat and light incidence, it can last the whole shelf life period indicated on the label with minimum oxidation.
What are the signs of deterioration in Castor oil?
Smelling is the best way to know if castor oil has gone bad. Oxidation is easily recognized as randicity.
You can also observe the oil color and consistency, it should be translucid. Turbidity and viscous consistency may indicate extensive oxidation and an oil like that should be immediately discarded.
Can you use castor oil that has expired?
Experts in the area of skincare and health do not recommend ingesting or applying castor oil to the hair, skin, or other parts of the body, especially if you observe any sign of rancidity.
Previous research showed that rancid oils contain free radicals, which are highly reactive molecules capable of harming cell membranes, proteins, and DNA .
In addition to free radicals, oxidized oils can also contain toxic compounds derived from the extensive transformation of fatty acids due to oxidation reactions.
According to studies, some of these compounds can be pro-carcinogenic and alter cell functions [2,5].
Moreover, previous research showed that castor oil has minor biological compounds including carotenoid, tocopherol, tocotrienol, phytosterol, and phenolic compounds .
Past the best-before date, these beneficial compounds may have been degraded over time, which could reduce the benefits of the oil.
Castor oil that has reached the end of its shelf life should be disposed of properly. Rather than throwing expired castor oil away, you should take it to an oil recycling center.
How to properly store Castor oil
Castor oil should be stored in a cool, dry, and dark place, away from the stove because of the heat. You can store it in a cupboard or in the refrigerator. Always keep the package well sealed to avoid air contact with the oil.
Adequate storage will delay fat oxidation and keep the chemical quality of castor oil, ensuring its beneficial properties.
In this short article, we answered the question, “Can castor oil go bad?” We also discussed the shelf life of castor oil and the best practices for storing it.
1. Yeboah A, Ying S, Lu J, Xie Y, Amoanimaa-dede H, Boateng KGA, et al.. Castor oil (Ricinus communis): a review on the chemical composition and physicochemical properties. Food Sci Technol [Internet]. 2021;41:399–413.
2. Vieira SA, Zhang G, Decker EA. Biological Implications of Lipid Oxidation Products. Journal of the American Oil Chemists’ Society. 2017;94(3):339-51.
5. A, Zarkovic N. Contribution of the HNE-immunohistochemistry to modern pathological concepts of major human diseases. Free Radical Biology and Medicine. 2017;111:110-26.