Castor Oil

Unique Fatty Acid Composition

Castor oil is unique among carrier oils because approximately 85-90% of its fatty acid content is ricinoleic acid, an unusual monounsaturated omega-9 fatty acid found almost exclusively in castor oil. Research published in the International Journal of Toxicology confirmed that ricinoleic acid possesses significant anti-inflammatory properties, which may explain many of castor oil's traditional therapeutic uses.

This exceptionally high ricinoleic acid content gives castor oil properties that are distinct from all other carrier oils — including its remarkable viscosity, deep penetration into the skin, and its traditional reputation for supporting hair growth and wound healing.

Hair Growth & Thickness

Castor oil is one of the most popular natural remedies for supporting hair growth and thickness. Whilst large-scale clinical trials are limited, its ricinoleic acid content may help improve scalp circulation and support the health of hair follicles. Additionally, castor oil's humectant properties help hair retain moisture, reducing breakage and creating the appearance of thicker, healthier hair.

Many people also apply castor oil to eyebrows and eyelashes to encourage fullness, though scientific evidence for this specific use remains largely anecdotal.

Anti-Inflammatory & Pain Relief

A study published in Mediators of Inflammation demonstrated that ricinoleic acid exhibits anti-inflammatory activity comparable to that of capsaicin. Castor oil packs (cloths soaked in castor oil and applied to the body) have been used in naturopathic medicine for decades to help reduce inflammation, ease joint pain, and soothe muscle tension.

Skin Healing & Moisture

Castor oil is a powerful humectant, drawing moisture from the environment into the skin. Its thick, occlusive nature also helps prevent transepidermal water loss. Research suggests that castor oil may support wound healing by creating a moist environment that promotes tissue repair. It is traditionally used for dry, cracked skin, calluses, and minor skin irritations.

Antimicrobial Properties

Laboratory research has shown that ricinoleic acid exhibits antimicrobial activity against a range of bacteria, yeasts, and moulds. A study in the Journal of the International Society of Preventive and Community Dentistry found that castor oil demonstrated antibacterial properties against oral pathogens. When combined with antimicrobial essential oils, castor oil may provide enhanced protective benefits for the skin.

Carrier Oil for Targeted Essential Oil Blends

Absorption rate: slow. Castor oil is extremely thick and viscous, so it is best used blended with a lighter carrier oil (such as jojoba or sweet almond) at a ratio of 20-30% castor oil to 70-80% lighter oil. This combination provides the benefits of castor oil's unique properties without being excessively heavy. Add essential oils at the standard 2-3% dilution.

Hair Growth Serum

Blend 1 tablespoon of castor oil with 1 tablespoon of jojoba oil and add 5 drops of rosemary essential oil and 3 drops of peppermint essential oil. Massage into the scalp using your fingertips for 3-5 minutes. Leave on for at least 1 hour (or overnight with a towel on the pillow) before shampooing out. Use 2-3 times per week consistently for several months.

Castor Oil Packs

Soak a piece of unbleached cotton flannel in castor oil and place it on the desired area (commonly the abdomen, lower back, or over joints). Cover with cling film and a warm towel or hot water bottle. Leave in place for 45-60 minutes. This traditional naturopathic technique is used to help ease inflammation, support digestion, and relieve muscle and joint discomfort.

Eyebrow & Eyelash Conditioning

Apply a small amount of castor oil to eyebrows and eyelashes using a clean mascara wand or cotton swab before bed. Some people add a single drop of lavender essential oil per 10 ml of castor oil. Be extremely careful to avoid direct contact with the eyes. Consistency over several weeks is key to seeing any potential results.

Cracked Heel Treatment

Castor oil's thick, occlusive texture makes it ideal for treating dry, cracked heels. Mix equal parts castor oil and coconut oil, add 5 drops of tea tree essential oil per 30 ml, and massage into the heels before bed. Cover with cotton socks overnight. The oil softens hard skin whilst the tea tree provides antimicrobial support.

Joint & Muscle Rub

Combine 1 tablespoon of castor oil with 1 tablespoon of sweet almond oil and add 4 drops of eucalyptus essential oil and 3 drops of ginger essential oil. Massage into sore joints or tense muscles. The ricinoleic acid in castor oil may help reduce inflammation, whilst the essential oils add warming or cooling analgesic properties.

Comedogenic Rating & Application

Comedogenic rating: 1 (out of 5) — very low. Despite its thick texture, castor oil has a surprisingly low comedogenic rating. However, its extreme viscosity means it is rarely used undiluted on the face. For facial use, blend with a lighter carrier oil at no more than 10-20% castor oil. Used in this way, it can actually help draw out impurities and balance oily skin.

Castor Bean vs. Castor Oil Safety

Castor oil is safe for topical use; castor beans are toxic. Raw castor beans contain ricin, an extremely toxic protein. However, the cold-pressing and refining process used to produce castor oil removes all traces of ricin. Commercially available castor oil is safe for external use. Nonetheless, castor oil should not be ingested without medical guidance, as it is a powerful laxative.

Shelf Life & Storage

Shelf life: approximately 1-2 years. Store castor oil in a tightly sealed dark glass bottle in a cool, dark place. Its thick consistency can make it slow to pour from the bottle — warming it gently in a bowl of warm water before use makes it easier to handle. Discard if it develops an unpleasant smell or changes colour significantly.

Pregnancy & Labour

Do not ingest castor oil to induce labour. Castor oil has been traditionally used as a folk remedy to induce labour, but this practice carries risks including severe nausea, diarrhoea, and dehydration. Topical use of castor oil during pregnancy is generally considered safe, but consult your healthcare provider before use. Avoid castor oil packs over the abdomen during pregnancy.