Most diffusers either require drops to be added to the machine or oil cartridges to be purchased from the manufacturer. Never use more than 8 drops of essential oil in a diffuser at one time—that’s pretty overkill. Anywhere between 3 and 8 drops is a good range. [2] X Expert Source Renee HughesCertified Professional Aromatherapist Expert Interview. 14 April 2022. Make sure you’re cleaning out your diffuser after each use! Regular cleanings prevent any essential oil residue from building up. [3] X Expert Source Renee HughesCertified Professional Aromatherapist Expert Interview. 14 April 2022.

The chemistry in rosemary is proven to help with cognitive function. [6] X Expert Source Renee HughesCertified Professional Aromatherapist Expert Interview. 14 April 2022. While it’s power is well-documented, you should avoid relying on rosemary oil to heighten awareness or help memory. The essential oil has not been tested for long term use to improve nervous system function. Using it once in a while is a better approach. [7] X Trustworthy Source PubMed Central Journal archive from the U. S. National Institutes of Health Go to source

If in doubt, check with your doctor’s office to see what they recommend. If you have pets in your home, you may want to look into the safety of rosemary oil for animals before using a diffuser.

Almond and jojoba oil are both very common carrier oils that won’t leave skin greasy, and will work to dilute rosemary oil. [10] X Research source Never apply an undiluted essential oil to your skin unless a licensed aromatherapist expressly tells you to. Undiluted oils can significantly burn your skin. [11] X Expert Source Renee HughesCertified Professional Aromatherapist Expert Interview. 14 April 2022.

Children and those who are pregnant should use much heavier dilutions, using only 3 to 6 drops per ounce. [13] X Research source Label the bottle as rosemary oil, plus the name of the carrier oil you used. A 2% dilution is great for massage oils. [14] X Expert Source Renee HughesCertified Professional Aromatherapist Expert Interview. 14 April 2022.

You can check for rancid carrier oil by smelling for a harsh, bitter odor, rather than the sweetness or odorless-ness of a fresh solution.

If you’re skin gets red, itchy, or bumpy, discontinue using rosemary oil and consider talking to your doctor about it.

A 1-2% dilution of rosemary oil is good for this. Massage it into your scalp every day to help encourage hair growth. [20] X Expert Source Renee HughesCertified Professional Aromatherapist Expert Interview. 14 April 2022. Using rosemary oil for at least 6 months can cause hair growth in cases of androgenetic alopecia, or “male pattern baldness”, indicating the power of this essential oil to help with overall hair health. The oil may also improve your scalp’s circulation.

You can also eat rosemary leaves to potentially relieve mild inflammation in your digestive system.

Avoid applying rosemary oil directly to an open wound.