Oil in jar

Castor oil and onion juice have both earned diehard devotees among natural hair care specialists. However, the two ingredients have key differences. Castor oil relies on moisturising fatty acids for hair repair, while the sting of onion juice comes from stimulating sulfur compounds.

When pitting them head-to-head for nurturing lustrous locks, can we pick a clear winner between these traditional favourites?

Let's evaluate the science and age-old wisdom behind their workings. Analyse why factors like hair type and scalp health govern choosing one over the other. By scrutinising all aspects of these natural remedies for hair rejuvenation, we can conclude whether castor oil or onion juice appears as the superior approach.

Castor oil vs. Onion juice for Hair Care


Castor Oil      

Onion Juice

Key Benefits           

Moisturises hair promotes growth, adds shine  

Fights hair fall, prevents greying, dandruff control


Rich in Vitamin E, omega-6 and 9 fatty acids, ricinoleic acid

High in sulfur, antioxidants, and flavonoids


Best mixed with a carrier oil  

Applied directly or mixed with other ingredients


It can be sticky and may require multiple washes to remove      

Strong smell, potential skin irritation

Castor Oil

What makes Castor oil special?

Castor oil, derived from the beans of the Ricinus communis plant, is a thick, yellow oil packed with vitamins, fatty acids, and other nutrients essential for healthy hair.

Amazing benefits of Castor oil for hair

  • Hydration and moisture: Castor oil moisturizes hair and scalp. It contains fatty acids that nourish hair with moisture, making it soft, smooth and shiny.
  • Enhanced hair health and shine: The omegas and antioxidants in castor oil condition hair strands. This restores health and smooth texture and gives a glossy shine.
  • Antibacterial and anti-fungal properties: Applying castor oil protects the scalp from infections. The substance present in it fights bacteria and fungus that cause dandruff or itchiness.
  • Vitamin E richness: Castor oil contains vitamin E, which improves blood circulation on the scalp. This allows better nutrient delivery to hair follicles.
  • Promoting hair growth: Massaging with castor oil boosts blood flow to hair roots. The fatty acids promote thicker, faster and longer hair growth.
  • Prevents split ends: The omega fatty acids in castor oil coat each strand, preventing moisture loss. This minimizes split and brittle ends.
  • Addresses scalp dryness: Castor oil is thick, so it creates an occlusive layer on the scalp. This prevents moisture loss and soothes inflammation or dryness.
  • Adds strength and luster: Applying castor oil strengthens the keratin component of hair, making each shaft stronger, more flexible and shinier.
  • Relieves Scalp Itchiness: The anti-inflammatory action of ricinoleic acid provides relief from itchy, irritated scalp conditions.
  • Hair Breakage Protection: Coating hair strands in castor oil's protective fatty layer prevents damage from frequent styling. Less breakage equals longer locks.

How to use Castor oil for hair?

Castor oil

Pure castor oil is very thick, sticky and dense. Diluting it with other hair oils helps enhance absorption while making application easier.

Added oils

  • Coconut oil - penetrates the hair shaft, antimicrobial
  • Olive oil - smoothens hair cuticle
  • Almond oil - vitamin E for moisture
  • Arnica oil - stimulates follicles
  • Mix castor with carrier oil in a 1:2 ratio

Application tips

  • Warm up the oil slightly before applying
  • Apply on the scalp using a cotton ball/fingertips
  • Use amount depending on hair length
  • For short hair - take almond-sized oil
  • For long hair - take approx 1 teaspoon
  • Massage gently through sections for 10-15 mins

How often

  • Overnight pre-wash conditioning: Weekly
  • Scalp massage for growth: 3 times a week
  • Leave-in hair serum for protection: Daily

Washing out

  • Castor oil coats strands, so it takes a few washes.
  • First, rinse with plain water.
  • Lather shampoo in palms before massaging onto the scalp
  • Rinse and shampoo twice, ensuring thorough removal.
  • Finally, condition hair properly

Precautions with Castor oil

Though castor oil is very moisturising, some best practices include:

  • Always mix it with lighter carrier oils - Using full castor oil, especially on sensitive skin, can be very occlusive and feel irritating. So diluting it minimises any risks.
  • Beware of fabric staining - Castor oil tends to leave oily residues, which can permeate clothes and bed linen, resulting in stubborn oil stains upon laundering. 
  • Wash out thoroughly post-treatment - Multiple washes with shampoo are needed to remove all the thick oil from hair follicles and skin pores after application. So lather up well and rinse off cleanly.

Onion juice

Why Onion juice?

Onion oil

Exploring the ayurvedic science behind onion juice and its rich composition that benefits hair.

Benefits of Onion juice for hair

  • Preventing hair fall: Onion juice contains sulfur, which strengthens hair follicles and strands to prevent breakage or shedding. This reduces hair fall significantly.
  • Fighting pre-mature greying: The rich antioxidants in onion juice hamper the enzyme, causing pre-mature greying. It maintains hair's natural pigment and colour.
  • Nourishing dry hair: The substance present in it encourages blood flow to the scalp, stimulating follicles. This nourishes dry, brittle hair, making it smooth and shiny.
  • Dandruff control: Onion juice has anti-fungal properties that restrain fungal growth, causing dandruff. Its antioxidants also soothe itchiness and inflammation.
  • Soothing scalp issues: Onion juice reduces scalp infections, sensitivity and irritation through its antimicrobial effects combined with anti-inflammatory activity.
  • Adds volume and bounce: Sulfur and antioxidants strengthen each strand, preventing breakage. This allows hair to grow longer and fuller.
  • Promotes thicker hair growth: Massaging onion juice stimulates better blood circulation, which enables improved nutrient delivery to follicles, promoting growth.
  • Moisturises hair: Onion juice keeps each shaft conditioned, preventing dryness or frizz, which minimises everything from split ends to knots and tangles.
  • Protects keratin: Keratin is hair's structural protein that onion antioxidants protect from oxidative damage caused by styling, chemicals or environmental pollution.

Extracting and applying Onion juice

Onion juice requires some preparation but works effectively to improve scalp and hair health.

Extracting juice

  • Peel the outer layer and chop 1-2 medium red or white onions.
  • Blend chopped pieces into a paste without adding water.
  • Wrap paste bundled up in a mesh strainer/cheesecloth.
  • Squeeze and press out the juice into a bowl below.

Mixing (optional)

  • To minimise pungency:
    • Add honey, aloe vera gel, yoghurt
    • Dilute with water if very strong
  • For added benefits:
    • Mix with amla, lemon, ginger juices


  • Section hair and apply juice onto the scalp using a cotton pad
  • Massage gently for 10-15 minutes
  • Focus extra on balding spots or areas of concern
  • For additional nourishment, comb paste through hair lengths

Dwell time

  • For severe hair issues, keep overnight with a shower cap
  • Otherwise, keep for a minimum of 30 mins
  • Rinse out thoroughly with a mild shampoo
  • Condition hair well afterwards


  • Limit to 2-3 times per week max.
  • Discontinue if the scalp feels irritated.

Side effects of Onion juice

benefits of onion oil

While onion juice is generally well-tolerated, some people may experience reactions like:

  • Stinging or burning sensation - Onion juice can initially cause a slight sting when applied. This normally fades. But very sensitive skin may react.
  • Skin irritation - Onions are from the allium family, which can irritate some people. Redness and rashes can appear on usage.
  • Increased hair dryness - The acidic pH of onion juice could make dry hair more dehydrated. Using a carrier oil helps prevent this.
  • Garlic-like body odour - The aromatic compounds from onion juice can seep into pores and sweat glands, causing body odour.

So do a 24-hour skin patch test before first use. Stop usage if any irritation persists and consult a dermatologist if it worsens.


Using natural ingredients like castor oil and onion juice for hair care connects us to ancient wisdom. These remedies work effectively, as modern research also shows. Castor oil deeply conditions hair, making it smooth and shiny. Massaging it on the scalp improves blood circulation there. 

This enables better hair growth. Onion juice strengthens hair strands and follicles through its sulfur. It prevents thinning and greying of hair. It also reduces dandruff. Both oils offer real benefits for hair health.

Castor oil uniformly suits all hair types. Onion juice gives the best results for oily hair prone to greying and dandruff. Their effects increase when blended with other herbs, too.


1. Can I use castor oil and onion juice together on my hair?

Yes, you can mix castor oil and onion juice for your hair treatment. Combining these two can maximise the benefits, as castor oil's moisturising properties complement the sulfur-rich onion juice, promoting hair growth and reducing hair fall. 

2. How often should I apply castor oil or onion juice to my hair?

For castor oil, starting with a once-weekly application is recommended, especially if it's your first time. Depending on your hair's response, you can increase this to two or three times a week. Onion juice can be applied two to three times a week right from the start.

3. Will onion juice make my hair smell bad?

Onion juice does have a strong smell, but it can be significantly reduced by rinsing your hair thoroughly with a mild shampoo after the treatment. 

4. Can I leave onion juice on my hair overnight?

It's not recommended to leave onion juice in your hair overnight due to its potent nature, which can potentially irritate the scalp. A maximum of 30 minutes to an hour is sufficient for onion juice to impart its benefits. 

5. What should I do if I experience irritation after applying castor oil or onion juice?

If you experience any irritation, itching, or discomfort after applying castor oil or onion juice, rinse it out immediately with plenty of water and a gentle shampoo. Discontinue use and consult with a dermatologist if the irritation persists.


Zandu Ayurvedic Team

Zandu Ayurvedic Team has a panel of over 10 BAMS (Ayurvedacharya), boasting a collective experience of over 50 years. With a deep-rooted understanding of Ayurveda, they are committed to sharing their expertise & knowledge through our blogs.
We use all kinds of Ayurvedic references in our content. Please use the contact form for any editorial queries.

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