Castor Oil and Coconut Oil for Hair: Mixing Guide
Short answer
Mix 1 part castor oil to 2 parts coconut oil — adjusting toward more coconut oil if it still feels heavy — for a more spreadable oil than castor oil alone. Castor oil is a thick surface sealant while coconut oil is thinner and better known for penetrating the hair shaft; neither has clinical evidence for growing hair, and combining them doesn't change that.
Castor and coconut oil solve different problems, which is why mixing them is popular rather than redundant. Castor oil is a thick, occlusive sealant; coconut oil is thinner and better known for penetrating the hair shaft. Neither has clinical evidence for growing hair: a systematic review of coconut, castor, and argan oil found no strong evidence supporting castor oil for growth [1]. But combined they make a more spreadable oil than castor oil alone, and that's the honest reason to reach for both.
| Castor oil | Coconut oil | |
|---|---|---|
| Texture | Very thick and occlusive. | Thinner, lighter feel, and easier to rinse. |
| Dominant fatty acid | Ricinoleic acid. | Lauric acid. |
| How it behaves on hair | Forms a strong surface film; coats and seals without absorbing into the shaft. | The only one of three oils in a bench study of hair fibres found to appreciably reduce protein loss [2]. |
| Evidence for hair growth | None. A systematic review found no strong evidence supporting castor oil for growth [1]. | None. |
How they differ
- Castor oil — very thick, high in ricinoleic acid, forms a strong surface film. Coats and seals; does not absorb into the shaft. See how castor oil works.
- Coconut oil — thinner, high in lauric acid, and the only one of three oils in a bench study of hair fibres found to appreciably reduce protein loss, whether applied before or after washing [2]. Lighter feel, easier to rinse.
Mixed, the coconut oil dilutes castor oil's thickness while both contribute film-forming and shaft-conditioning properties — a practical middle ground rather than a synergy with special evidence behind it.
How to mix them
- Ratio: start at 1 part castor oil to 2 parts coconut oil, and adjust toward more coconut oil if the mix still feels heavy.
- Fractionated vs. regular coconut oil: fractionated coconut oil stays liquid at room temperature and blends more evenly; regular (virgin or refined) coconut oil solidifies below about 76°F (24°C) and may need gentle warming to combine.
- Warm gently if needed. A few seconds in warm water, not the microwave, softens solid coconut oil enough to blend without overheating either oil.
- Patch test the blend, not just each oil separately — see the full application guide for patch-testing and dilution basics.
- Want a measured recipe? The castor oil hair mask recipes give exact quantities and leave-in times, and the same ratios work with coconut oil as the lighter base.
Best uses for the blend
- Pre-wash treatment. Apply to dry lengths and scalp 30 minutes to a few hours before shampooing; the coconut oil's better spreadability makes sectioning easier than with castor oil alone.
- Sealing damp ends. A few drops after washing, concentrated on the driest length — useful for natural hair and locs, where straight castor oil can be too heavy to distribute evenly.
- Scalp massage. The lighter blend spreads with less tugging than thick castor oil, which matters most around fragile edges and hairlines.
What the blend does not do
Neither oil has trial evidence for regrowing hair or reversing thinning, and mixing two unproven ingredients does not create a proven one. If retained length from less breakage is the goal, this blend is a reasonable tool. If shedding or thinning is the actual concern, start with the hair loss guide instead of a new oil combination.
Buying the two oils
This site tracks pure castor oil pricing directly; pair it with any coconut oil, fractionated or regular, sold separately. Current pure castor oil listings by price per fluid ounce:
| Product | Price | $ / fl oz |
|---|---|---|
| US+ Castor Oil Cold Pressed, 100% Pure, USP Grade - 1 Gallon | $34.99as of Sep 15, 2026, 11:51 AM ET | $0.27/fl oz |
| GreenIVe 100% Pure Castor Oil, 32 Fl oz | $17.99as of Sep 15, 2026, 11:51 AM ET | $0.56/fl oz |
| US+ Cold Pressed Castor Oil, 100% Pure, USP Grade - 10 Fl Oz (300 ml) | $6.99as of Sep 15, 2026, 11:51 AM ET | $0.70/fl oz |
| Jamaican Mango and Lime Black Castor Oil, Original, 8 Ounce | $13.65as of Sep 15, 2026, 11:51 AM ET | $1.71/fl oz |
| GreenIVe 100% Pure Castor Oil, 4 Fl oz | $7.50as of Sep 15, 2026, 11:51 AM ET | $1.88/fl oz |
| Botanic Hearth Castor Oil for Hair Growth with Pumpkin Seed Oil, Hair Growth Oils for Thinning Hair, Dry Damaged Hair & Scalp Treatment, Strengthens & Nourishes Hair, 6.7 fl oz | $13.99as of Sep 15, 2026, 11:51 AM ET | $2.09/fl oz |
| Majestic Pure Castor Oil - 4 Fl Oz with Applicator | $8.99as of Sep 15, 2026, 11:51 AM ET | $2.25/fl oz |
| Botanic Hearth 100% Pure & Natural Jamican Castor Oil - 8 Fl oz | $17.99as of Sep 15, 2026, 11:51 AM ET | $2.25/fl oz |
Common questions
Frequently asked questions
- What is the ratio of castor oil to coconut oil for hair?
- Start at 1 part castor oil to 2 parts coconut oil, and adjust toward more coconut oil if the mix still feels heavy. Patch test the finished blend, not just each oil separately.
- Is castor oil or coconut oil better for hair?
- They do different jobs: castor oil is a thick, occlusive sealant that coats the surface, while coconut oil is thinner and one of the few oils shown in lab studies to reduce protein loss from the hair shaft. Neither has clinical evidence for growing hair.
- Should I use fractionated or regular coconut oil in the mix?
- Fractionated coconut oil stays liquid at room temperature and blends more evenly. Regular (virgin or refined) coconut oil solidifies below about 76°F (24°C) and may need gentle warming in warm water — not the microwave — to combine.
- Does mixing castor and coconut oil help hair grow?
- No — neither oil has trial evidence for regrowing hair or reversing thinning, and mixing two unproven ingredients does not create a proven one. The blend is a reasonable tool if the goal is retained length from less breakage.
Ready to compare products?
Compare pure cold-pressed castor oil by current price per fluid ounce.
Sources
- Phong C, Lee V, Yale K, Sung C, Mesinkovska N. Coconut, Castor, and Argan Oil for Hair in Skin of Color Patients: A Systematic Review. Journal of Drugs in Dermatology 21(7):751–757, 2022. View source
Supports: A systematic review of 22 articles concluding there is weaker evidence that castor oil improves hair luster and no strong evidence supporting its use for hair growth.
- Rele AS, Mohile RB. Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage. Journal of Cosmetic Science 54(2):175–192, 2003. View source
Supports: A laboratory study of three oils on hair fibres finding coconut oil was the only one of the three to reduce protein loss appreciably, on both undamaged and damaged hair and whether applied before or after washing, which the authors attribute to lauric acid penetrating the shaft. It is a bench study of hair fibres, not a clinical trial, and it says nothing about hair growth.