Castor oil is the heaviest and thickest oil in our selection. That makes it both the most talked-about and the most frequently misused. Applying pure castor oil directly to the hair without dilution often results in a heavy, sticky outcome. However, using it intentionally and in the correct ratio yields an oil with a unique composition that differs significantly from most other plant-based oils. Before we begin, we want to address a common claim: the idea that castor oil makes your hair grow faster is largely a myth (more on this in the FAQ). This article explains what makes castor oil chemically unique, how to dilute it, and which applications make the most sense. For a comprehensive overview of all its uses, read our guide on what castor oil is good for.
1. What makes castor oil different: ricinoleic acid
Most plant oils consist primarily of a combination of oleic acid, linoleic acid, and palmitic acid. Castor oil is a notable exception: more than 85 percent of its fatty acid profile is made up of ricinoleic acid, a hydroxy fatty acid that is virtually non-existent in any other plant oil in this concentration.1
The hydroxyl group in the ricinoleic acid molecule is key to how castor oil behaves. It makes the oil exceptionally viscous and occlusive, meaning it forms a dense, persistent film on the surface where it is applied. This film does not evaporate quickly and is more difficult to rinse away than most other oils. This is both castor oil's greatest strength and its primary challenge: it clings, it stays put, and it requires an intentional approach.
For more context on how oils work on the hair and scalp in general, you can read our comprehensive guide to hair and scalp health.
Ricinoleic acid is present in significant amounts in fewer than a handful of plant oils worldwide. Castor oil is the only one that is commercially available and suitable for cosmetic use.
Our position: We do not sell castor oil as a hair growth remedy, even though much of the market does. The evidence simply is not there. What it does offer is a unique, rich oil that demonstrably improves the suppleness of dry and porous hair, provided you dilute and rinse it properly. We prefer to share this honest perspective, as we believe well-informed customers are those who return.
2. Castor oil compared to other plant oils
The differences in composition and texture between castor oil and other oils in our selection are substantial. The table below highlights where castor oil stands in relation to lighter oils.
| Oil | Texture | Key Fatty Acid | Best Suited For |
|---|---|---|---|
| Castor oil | Very thick, viscous | Ricinoleic acid (85%+) | Hair shaft, high porosity, diluted use |
| Avocado oil | Medium-weight | Oleic acid | Dry, thick hair, high porosity |
| Argan oil | Lightweight | Oleic acid, linoleic acid | All hair types, hair shaft, and scalp |
| Jojoba oil | Very lightweight (liquid wax) | Wax esters | All hair types, including oily scalp |
The difference in texture is immediately noticeable: castor oil has a consistency similar to honey, while argan or jojoba oil flows like water. This is why castor oil does not work as a direct, daily leave-in treatment, though it is highly valuable in a thoughtfully crafted blend or as a targeted treatment.
3. Why dilution is necessary and how to do it
When applied pure to the hair, castor oil is too heavy for most people to distribute evenly. The oil tends to clump, spread unevenly, and become difficult to rinse out. Diluting it with a lighter oil resolves this: the resulting blend retains the protective, occlusive qualities of the castor oil while gaining the lightweight texture and ease of application of the carrier oil.
Ratios as a starting point
There is no single ratio that works for everyone, but the guidelines below offer a practical starting point. It depends on hair porosity, hair density, and how you intend to use the mixture.
| Application | Ratio of castor oil to lighter oil | Recommended carrier oil |
|---|---|---|
| Pre-wash hair mask | 1 : 3 to 1 : 4 | Argan oil, avocado oil |
| Cils et sourcils | Pure or 1 : 1 | Jojoba oil |
| Scalp treatment | 1 : 5 or more | Jojoba oil, macadamia oil |
| Soin des pointes sèches | 1 : 4 to 1 : 5 | Argan oil, baobab oil |
Mix the oils immediately before use, or prepare a larger batch in a small bottle. Castor oil is highly stable and oxidizes slowly, meaning a pre-made blend will remain fresh for weeks when stored at room temperature away from direct sunlight.
Always start with less castor oil than you think you need. You can easily adjust the ratio during your next treatment, but having too much castor oil in a blend is difficult to correct without adding significant amounts of carrier oil.
4. Castor oil for the hair shaft: when and how
The occlusive nature of castor oil is highly beneficial for the hair shaft, especially for high-porosity hair. High-porosity hair has raised or damaged cuticles that absorb moisture quickly but lose it just as fast. A richer oil that remains on the surface helps seal the cuticle and prevent moisture loss. You can learn more about how porosity determines your choice of oil in our blog post on hair porosity and oils.
Pre-wash hair mask
The most effective way to use castor oil on the hair shaft is as a pre-wash treatment. The oil is applied before washing to protect the cuticle during cleansing, and is then washed away with shampoo. This allows you to benefit from its conditioning properties without leaving a heavy residue in your hair.
- Associez l'huile de ricin à une huile plus fluide dans un ratio de 1:3 ou 1:4.
- Appliquez le mélange sur cheveux secs ou légèrement humides (essorés à la serviette), des demi-longueurs jusqu'aux pointes.
- Massez doucement pour bien répartir le soin et laissez poser 20 à 45 minutes (davantage si vos cheveux sont très épais ou très secs).
- Procédez ensuite à un lavage minutieux à l'aide d'un shampooing doux. Deux applications peuvent s'avérer nécessaires pour éliminer parfaitement les résidus huileux.
Soin ciblé des pointes sèches ou abîmées
For dry ends, a highly diluted blend (mostly consisting of carrier oil) can be applied to dry hair as a targeted leave-in treatment. Use just a single drop of the mixture, warming it in your hands before applying to the very tips. Avoid moving toward the roots.
5. Castor oil on the scalp: use with caution
Applying castor oil to the scalp requires extra care. If overused, its thick, occlusive texture can build up around the hair follicles, leading to a heavy or congested feeling. Consequently, castor oil is generally not a good option for oily or highly sensitive scalps, where lighter choices like jojoba oil are much more suitable.
For a dry scalp that can tolerate a richer treatment, highly diluted castor oil can be used as an occasional pre-wash treatment. Prepare a mixture with at least five parts lighter oil to one part castor oil, apply it to the scalp, massage gently, and rinse thoroughly after 20 to 30 minutes. This should not be a daily or weekly routine, but rather an occasional supplement when the scalp feels exceptionally dry.
Due to its thickness, castor oil is more difficult to rinse out fully than lighter oils. Inadequate rinsing is one of the most common causes of build-up. To learn how to identify and prevent this, read our blog post on product build-up and hard water.
6. Other applications: eyebrows, eyelashes, and nails
Outside of standard hair care, castor oil is also used for targeted treatment of small areas where its occlusive, protective properties are highly advantageous.
Cils et sourcils
Castor oil can be applied pure or slightly diluted to eyebrows and eyelashes using a clean spoolie or cotton swab. The occlusive film shields the hairs and protects the underlying skin. Apply a tiny amount in the evening and gently remove any excess the next morning. Take care to avoid direct contact with the eyes. For detailed application steps, read our blog post on natural care for fuller lashes.
Cuticles and nails
Castor oil is a classic choice for cuticle care. The thick texture stays in place well and absorbs slowly. Massage a tiny drop into the cuticle area before going to sleep.
Lèvres et zones rugueuses
Its occlusive properties also make castor oil useful as a protective barrier on dry lips or cracked skin. Use it pure or blended with a lighter oil to seal in moisture on troubled spots.
7. When is castor oil not a good choice?
Castor oil is not suitable for every hair type or situation. It is helpful to know when it is better to opt for a lighter oil.
- Fine or low-porosity hair: The heavy texture tends to sit on the surface of the hair, quickly weighing it down. Lightweight oils such as jojoba or argan oil are much better suited here.
- Oily scalp: Castor oil is too occlusive for daily or regular use on a scalp that already leans oily. This can congest the hair follicles.
- As a daily leave-in: Castor oil is a treatment oil, not a daily styling or conditioning oil. Daily application will quickly lead to build-up.
- With existing build-up: Do not apply a rich, heavy oil if you already have product build-up. Remove the existing residue first before reintroducing castor oil.
8. Products
Organic, cold-pressed. Rich in ricinoleic acid. Suitable for pre-wash treatments, eyebrows, and nails. Always dilute when using on hair.
A blend of argan oil and avocado oil. A lighter base to dilute castor oil for a perfectly balanced hair mask mixture.
Lightweight texture, rich in vitamin E. An ideal blending partner for castor oil in pre-wash treatments or for the ends of the hair.
Medium-weight, highly penetrating. Pairs beautifully with castor oil for a richer pre-wash blend on dry or chemically treated hair.
Visit our castor oil collection page to see all available variants, or explore our full range of natural oils for other blending options.
Sources
- Patel VR, Dumancas GG, Kasi Viswanath LC, Maples R, Subong BJJ. Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production. Lipid Insights. 2016;9:1-12.
- Use of Castor Oil in Dermatology: A Narrative Review. PubMed Central (PMC), 2024.
Frequently asked questions
Castor oil: what is it good for and what is it used for?
Castor oil is used externally on dry skin areas (such as elbows, heels, and lips), around the eye area, on eyebrows and eyelashes, on the scalp and hair ends, and as part of the oil cleansing method. The film-forming properties of ricinoleic acid make it highly versatile as a protective, sealing care step for dry and delicate zones.
What is the difference between cold-pressed, refined, and black (Jamaican) castor oil?
Cold-pressed (golden-yellow) castor oil is extracted without heat, which best preserves its beneficial fatty acids. Refined or expeller-pressed oil is clearer and virtually odorless, but lacks some of the active components. Black (Jamaican) castor oil is made from roasted seeds, has a dark color, and is popular for hair care, but is not inherently superior—just processed differently. For skin and hair care, always opt for cold-pressed, preferably organic.
Castor oil for eyes: how do you use it around the eye area?
Apply a tiny amount of castor oil to the skin around the eyes with a clean finger or a cotton swab, never directly into the eye. Always use it diluted in jojoba oil. The skin around the eyes is exceptionally thin and sensitive; a single tiny drop for the entire area is sufficient. Apply it as the final step in your evening routine, keeping it away from the eyeball.
Is castor oil good for eyebrows and how do you use it?
Use a clean spoolie or a cotton swab to apply a small amount of castor oil along your brow hairs in the direction of growth. Use this as an evening treatment. Avoid excessive amounts, as too much can feel greasy and spread to surrounding skin. A small bottle with a brush applicator is the most convenient tool for daily use.
Castor oil for psoriasis and dry, flaky skin: how do you use it?
On dry, flaky skin areas such as elbows or knees, castor oil is used as a supplemental occlusive step. Apply it after a lighter oil to seal the skin and prevent moisture loss. For psoriasis or other chronic skin conditions, it is best to consult a dermatologist before incorporating castor oil into your routine.
Castor oil for eczema: is it suitable for dry, irritated skin?
For dry, sensitive, or mildly irritated skin, castor oil is sometimes used as a supplemental, protective outer layer over a lighter nourishing oil. Its film-forming properties can help keep the skin protected. Always perform a patch test before using castor oil on highly reactive skin. For eczema or other skin issues, castor oil is not a substitute for medical treatment.
Castor oil for joints: what is its topical use?
In traditional practices, castor oil is applied topically to the skin surrounding joints. This is strictly a cosmetic, external skin application, not a medical treatment. Gently rub a small amount into the skin around the joint. For persistent joint issues, a medical consultation is always recommended.
Is castor oil good for hair growth?
Scientific evidence for a direct effect on hair growth is limited; faster or thicker hair from castor oil is largely a myth. What castor oil actually does: it conditions the scalp skin, keeps the tissue around the hair follicles supple, and limits moisture loss. Regular scalp massages stimulate circulation, which can benefit overall scalp health.
What is the difference between castor oil, ricinus oil, and castorolie?
Castor oil, ricinus oil, and "castor oil" are three names for the exact same product: the oil extracted from the seeds of Ricinus communis. "Castor oil" is the English term, while "castorolie" and "ricinusolie" are the Dutch names for the same oil. Please note: ricinus oil sold as a laxative is a separate medical product and is not the same as cosmetic, cold-pressed castor oil meant for topical application.
Can I use castor oil pure on my face?
For the majority of people, pure castor oil is too heavy for the face. Always dilute it with a lighter oil (jojoba, argan) in a ratio of one part castor oil to two or three parts carrier oil. Using it pure is only practical on specific dry areas of the body.
Peut-on utiliser l'huile de ricin pendant la grossesse?
Topical cosmetic application on the skin is very different from internal ingestion or castor oil packs, both of which are discouraged during pregnancy. Exercise caution and, when in doubt, always consult your midwife or doctor before adding castor oil to your routine. This article does not replace professional medical advice.
Castor oil side effects: what should you watch out for?
Castor oil is well tolerated by most people for topical use. Potential considerations: its high comedogenicity rating can lead to clogged pores for oily or acne-prone skin; sensitivity to ricinus oil is possible for those with an allergy to the castor oil plant. Always perform a patch test in the crook of your elbow 24 hours prior to first use. Discontinue immediately if irritation or redness occurs.
How do I get castor oil out of my hair?
Due to its thick texture, castor oil can be stubborn to wash out. Apply shampoo to dry hair before wetting it. This helps the shampoo emulsify and lift the oil. Afterward, rinse thoroughly with warm water. Repeat the shampoo step if the oil is not completely removed. Be sure to use a smaller amount in your next treatment.
How long does castor oil keep and how do you store it?
Castor oil is relatively stable and typically keeps for one to two years after opening when stored in a cool, dark place. The high concentration of ricinoleic acid makes it more stable than oils containing large amounts of polyunsaturated fatty acids. A changed odor or a cloudy appearance are indicators of oxidation. Do not apply oxidized oil to your skin.
Castor oil in the ear: is it safe and how is it used topically?
Traditionally, castor oil is also applied topically around the ear—onto the outer cartilage or the soft skin behind the ear. This falls strictly under external cosmetic skin care. Dripping castor oil directly into the ear canal is outside the scope of cosmetic skincare use. For ear complaints or hearing issues, always consult a general practitioner.
Best castor oil for face and hair: what should you look for when purchasing?
The best castor oil for face and hair is cold-pressed and, ideally, certified organic. Cold-pressing preserves beneficial fatty acids much better than heat extraction methods. Pure cold-pressed castor oil has a pale yellow tint and a recognizable mild aroma. Heavily bleached or completely odorless variants are often refined. For use around the eyes, brows, and lashes, 100% pure, unrefined quality is the most reliable choice.
Découvrez également notre huile de ricin et notre collection d'huiles naturelles.
