Using essential oils safely on your hair and scalp

Essential oils are powerful, and that is the reason they need rules. The most important one is short: they go in your products, not on you.

Why neat essential oil is the problem

Essential oils are concentrated plant compounds. Applied undiluted to skin, they are the main cause of sensitisation in aromatherapy.

Sensitisation is not the same as irritation. Irritation is visible, immediate and goes away. Sensitisation is an immune response. It builds silently over repeated exposures, it can be permanent, and it can cross-react: someone sensitised to one compound can start reacting to other oils and to fragranced products around the home.

What matters is the concentration against your skin, not the quantity. Three drops of neat peppermint on a parting is still one hundred percent peppermint. A small amount of an undiluted oil is not a small dose in the way that counts.

The safe way: dilute first

Carrier oils are pressed from nuts, seeds and fruit and are generally safe on skin. Essential oils are used in them at fractions of a percent up to low single digits. That is how No 01 and No 02 are made: essential oils carried in plant oils.

If you add essential oil to your own routine, it goes into something else, every time:

• Into the shampoo already in your palm.
• Into a conditioner or hair mask.
• Into a carrier oil.

What not to do

• Straight on the scalp? No. It goes into your shampoo, your conditioner or your carrier oil, never onto skin on its own.
• In the bath? No. Oil does not mix with water. It floats as neat droplets and lands on your skin at full strength. This is a real burn risk, and it is common internet advice.
• Near the eyes, brows or lashes? No. Peppermint can travel as vapour from the hairline to the eyes.
• Swallowed? Never. External use only.

Before you use any oil on your hair

• Patch test. Behind the ear or inside the elbow, 24 hours, before first full use.
• A cool tingle is normal with peppermint. Burning, stinging or redness is not. Wash it out and stop.
• Nut allergy. No 01 and No 02 contain sweet almond oil, and No 02 also contains coconut oil. Please speak to your doctor first.
• Pregnancy, breastfeeding, and children. Please check with your doctor.
• Broken skin or a diagnosed scalp condition. Do not use. See a dermatologist.

Read next: Using hair oils well.