Essential oils obtained from citrus trees – orange, lemon, grapefruit, etc… – are usually the least expensive oils used in aromatherapy. With their uplifting scents and cheaper price tag they are very popular amongst the layperson and aroma-hobbyists. Unfortunately they also have a relatively short shelf life and care should be taken to obtain the freshest oils available to prevent unwanted effects from a degraded oil.
Tips for shopping for fresh citrus oils
Retail shops that sell a variety of health goods products don’t typically have an educated aromatherapy specialist on staff, and little information may be known about distillation years or batch numbers. It doesn’t hurt to ask though! You’ll want to know:
- What year was this oil distilled in? (best if less than 12 months old)
- How long has this oil been stocked? (a film of dust on the caps is never a good sign!)
- Has the bottle I am purchasing been opened? (never use a sample bottle that has a good chance of being oxidized with repeated exposure to oxygen by opening the cap)
- Is this essential oil being stored under refrigeration?
If you’re shopping online call the business and get these answers over the phone.
Safety concerns for oxidized citrus oils
In addition to have an “off” odor the chemical properties change due to: heat, months or years on a shelf, and the bottle’s cap being removed time and time again. The original therapeutic properties of the oil may be diminished or non-existent and this new chemistry in the aged bottle holds a risk for being unsafe on the skin.
In a 2004 study researchers looked at lemon oil over the course of 12 months. The oil was stored at 77°F for the year and the cap was removed every day for a total of three minutes. One of the natural chemical constituents, limonene, was observed at the beginning of the study and found to be at 68.5%. By the end of the study the limonene had gone down to 20.1%, (Sawamura et al 2004).
With oxidization comes a greater chance of skin sensitization, which is a permanent and unpleasant experience. Note Marge Clark’s personal reaction to lavender:
“One of my mentors reminds me ‘sensitization is forever.’ And I know she is right. Years ago I read the books saying that lavender oil could be used neat (undiluted). I very unwisely used undiluted lavender on broken skin, and consequently set up a sensitivity reaction. Today, almost two decades later, if I come in contact with lavender in any form, I will immediately start a new round of contact dermatitis that can take months to heal.”