Description
Aug 17th, 2026 | 4 minute read
This DIY Rosemary Hair Serum is a simple oil-based hair serum made with plant oils and rosemary essential oil. It can be used as a scalp massage oil before washing your hair, or as a tiny amount on dry hair ends to help them look smoother and shinier.
| Ingredient | Amount | Why It's Used |
|---|---|---|
| Jojoba Oil | 51.5 mL | A light oil that spreads easily and does not feel too heavy on the scalp. It helps to maintain moisture whilst allowing skin to breathe. |
| Argan Oil | 30 mL | Helps hair look smoother, softer and shinier and is an excellent oil for skin care. |
| Castor Oil | 15 mL | A thicker oil that helps coat dry hair and adds richness to the serum. |
| Rosemary Essential Oil | 1 mL | Adds a fresh herbal scent and is commonly used in scalp oil blends. |
| Peppermint Essential Oil (optional) | 0.5 mL | Adds a cool, fresh feeling. Leave it out if your scalp is sensitive. |
| Vitamin E Oil | 2 mL | Added to oil blends to help prolong their shelf life. |
| Total | 100 mL |
Apply 3–8 drops to your scalp. Use your fingertips to gently massage it in for a few minutes. Leave it on for at least 30 minutes, then wash your hair as normal.
You can also leave it on overnight if your scalp is comfortable with oils. Use a towel over your pillowcase to avoid oil marks.
Rub 1–2 drops between your palms, then smooth lightly over the ends of your hair. Start with less than you think you need. Too much oil can make hair look and feel greasy.
Use 2–4 times per week as a pre-wash scalp oil. For hair ends, use only when needed.
Do not use the serum if:
- It smells sour, stale or unusual.
- The colour changes a lot.
- It looks cloudy, especially during warm or hot weather.
Note: During cold weather, jojoba oil may start to solidify and cause the serum to look cloudy. If the cloudiness disappears when the temperature increases slightly, the oil should still be okay to use. - It has been stored in heat or direct sunlight for too long.
This will make the serum feel lighter and easier to wash out.
internally. This product is not intended to diagnose, treat, cure, or prevent any medical
condition.
First Published: 24 August 2026 | Last Updated: 25 August 2026
Additional Details
FAQ's
Can I put rosemary essential oil straight on my scalp?
No. Rosemary essential oil is very strong. It should always be mixed with a carrier oil first, such as jojoba oil, argan oil or another suitable plant oil.
This recipe already mixes the rosemary essential oil into other oils, so it is diluted before you use it on your scalp.
Is this the same as rosemary oil for hair growth?
This recipe is a cosmetic hair and scalp oil. It is made to help care for your hair and scalp.
Many people use rosemary essential oil in scalp oil blends, but this serum is not a treatment for hair loss.
If you are losing more hair than usual, have bald patches, scalp pain or sudden hair shedding, speak with a healthcare professional.
How often should I use this rosemary hair serum?
Start with once a week.
This gives you time to see how your scalp and hair feel. If your scalp feels fine and your hair does not get too oily, you can use it up to 2–4 times per week as a pre-wash oil.
How long should I leave it in my hair?
Leave it on for at least 30 minutes before washing your hair.
You can also leave it on overnight if your scalp feels comfortable. Place a towel over your pillowcase so the oil does not mark the fabric.
Do I need to wash it out?
If you use it on your scalp, most people will want to wash it out with shampoo.
If you use it only on dry hair ends, you can leave it in. Use just 1–2 drops. Start with a tiny amount so your hair does not look or feel greasy.
Will it make my hair greasy?
It can make your hair greasy if you use too much.
For your scalp, start with only 3–8 drops. For hair ends, start with 1 drop.
You can always add more, but it is much harder to remove too much oil once it is already in your hair.
Can I use this serum if I have fine or oily hair?
Yes, but use less.
Fine hair and oily hair can look greasy more quickly. Start with a very small amount.
You can also make a lighter version of this recipe by replacing the 15 mL castor oil with an extra 15 mL jojoba oil.
Can I leave out the peppermint essential oil?
Yes. Peppermint essential oil is optional.
It can feel cool and fresh on the scalp, but it may be too strong for some people.
If you leave it out, add 1 mL extra jojoba oil so the recipe still makes 100 mL in total.
Can I use this on coloured or chemically treated hair?
Is rosemary water the same as this rosemary hair serum?
Does this serum need a preservative?
No, not if made with fresh ingredients and clean equipment. This serum has a low risk of microbial contamination because it does not contain water.
To help keep this serum fresh:
- Keep water out of the bottle
- Close the lid after use
- Do not touch the bottle opening with wet fingers
- Store it in a cool, dry, dark place
What should I do if my scalp feels itchy, hot or sore?
Wash the serum out with shampoo and stop using it. A light cooling feeling can happen if peppermint essential oil is included. But burning, stinging, redness or strong itching is not normal.
Do not keep using it if your scalp feels irritated.
Can children use this hair serum?
This recipe is designed for adults.
Do not use essential oils on children unless you have checked with a qualified healthcare professional first.
If you want to make a gentler oil for a child, leave out the rosemary essential oil and peppermint essential oil unless you have proper advice.
Can I use this if I am pregnant or breastfeeding?
Check with a qualified healthcare professional before using essential oils during pregnancy or breastfeeding.
For a gentler option, you can make a simple hair oil using only carrier oils, without essential oils.
- SKU:
- RCP-RHSE
