What is Grapefruit Seed Extract?

Grapefruit seed extract or GSE is a compound which is extracted from the seeds, fleshy white membrane, and pulp of the grapefruit, a large citrus fruit which has been cultivated for its tart flesh for centuries. Many people who are interested in alternative health have promoted GSE for various alleged properties, leading scientists to study the compound more closely to see whether or not these claims have merit. Thus far, most of the claims about grapefruit seed extract have been disproved, and some studies have even showed that the substance might actually be harmful in certain circumstances.

Credit for the discovery of GSE is usually given to Jacob Harich. Cynics suggest that Harich simply wanted to find a way to use leftover grapefruit pulp after juicing, while proponents of the substance sometimes credit him with divine inspiration. The truth probably lies somewhere in the middle.

The primary claims made about grapefruit seed extract are that the substance has antifungal, antibacterial, and antiviral properties. Some people also say that GSE can be used as a preservative, since it fights off unwanted organisms. However, studies of the compound have questioned whether or not these claims can be supported, not least because producers add synthetic stabilizers and preservatives to their grapefruit seed extract before sending it to market. As a result, the preservative effects of GSE could be due to the extract or to the adulterations which are added; studies on pure GSE have cast some doubts on the efficacy of the substance as a preservative.

What grapefruit seed extract definitely does contain is antioxidants and ascorbic acid, also known as vitamin C. The extract also contains small amounts of natural citrus oils. Citrus oil can be good at fighting off fungi, bacteria, and viruses, suggesting that GSE may be at least weakly effective at these tasks as well. People who make grapefruit seed extract at home use it for a variety of purposes including skin care and in natural household cleaners; it can also be purchased in health food stores.

People who are interested in grapefruit seed extract should be careful. Some commercial GSE can actually cause allergic reactions because of the preservatives it uses; if you want to use grapefruit seed extract for skincare, try to find some which is labeled “food grade.” You may also want to research other natural ways of fighting unwanted organisms, as some natural compounds are actually quite effective; for example, citrus juice is a mild antibacterial, which is why it appears in many natural cleaning products.