How to Make Rosemary Oil for Hair at Home

Method

1. Sterilise the jar and bottle

   Wash the jar, lid and bottle, then boil them for 10 minutes and let them air-dry completely. Wet glass adds water, which is exactly what you are trying to keep out.^3,4

2. Measure the dried rosemary into the jar

   Put 4 tbsp (about 8 g) of dried rosemary in the jar and crush it lightly with the back of a spoon. Check the leaves are properly dry and crisp; leaves that bend or feel damp can still carry water.³

3. Warm infusion: heat the oil

   Warm 1 cup (240 ml) of your carrier oil in a small pan to 82°C (180°F), checking with a thermometer, and no hotter. Extension food-safety advice uses this temperature for dried herbs.^3,4

4. Warm infusion: pour, cool and steep

   Pour the hot oil over the rosemary, leaving about 1 cm (half an inch) of space at the top, then cap the jar. Leave it to cool to room temperature, about 2 to 3 hours, giving it a gentle swirl now and then.⁴

5. Strain and bottle

   Strain through a fine sieve lined with muslin into the clean dark bottle, pressing the leaves gently. Discard the used rosemary rather than reusing it.

6. Refrigerate and label

   Label the bottle with the date and put it in the fridge straight away. The University of Georgia advises refrigerating an infusion made with dried or fresh herbs and heat and throwing it away after 4 days. University of Maine allows up to 3 months in a cool, dark place. We follow the stricter advice, so make small batches. Olive and coconut oil turn cloudy or solid in the fridge; let the bottle stand at room temperature for a few minutes before using.^3,4

7. Slow infusion: the two-to-four-week version

   For a cold infusion, put the dried rosemary and unheated oil in the sterilised jar, cap it and leave it for two to four weeks, shaking it every few days. Neither extension source tests this method, and heat is part of their safety advice, so keep the jar in the fridge for the whole time, strain it at the end and treat it like the warm version. If it smells sour, looks cloudy or shows any bubbles or mould, throw it away.³

8. Diluting rosemary essential oil instead

   Measure 30 ml (2 tbsp) of carrier oil into a clean dark bottle and add about 6 drops of rosemary essential oil, then swirl to mix. This is about a 1% dilution and is our cautious starting point, not a figure from the trials. Never put essential oil on your scalp undiluted.^5,6

9. Patch-test, then use

   Dab a little on your inner forearm and wait 24 hours before putting any of it on your scalp. If it is fine, massage a small amount into your scalp, keep it away from your eyes, and shampoo it out after a while. Stop if you get itching, redness or a rash.^5,6

Variations

Does it actually work?

The best human evidence is a small trial of 100 people with androgenetic alopecia (pattern hair loss), who used rosemary oil or 2% minoxidil for 6 months. Hair counts rose in both groups by 6 months, with no significant difference between them, and nothing changed at 3 months. There was no placebo group, so it cannot show that rosemary worked better than doing nothing. It also tested a rosemary oil product, not a home infusion, and it is not known whether an infusion delivers a comparable dose. An older trial of alopecia areata used a blend of four essential oils in carrier oils (thyme, rosemary, lavender, cedarwood) with 44% improved against 15% with carrier oil alone, but that is a different condition and cannot single out rosemary. The abstracts of both trials do not give the dilution used. Our /ingredients/rosemary-oil/ entry rates the evidence.^1,2

Evidence ratings for what goes in: Rosemary oil, Olive oil, Jojoba oil, Coconut oil.

Questions people ask