Onion is known for its strong scent and flavorful nature. A dash of onion is enough to turn any dish delicious. The humble onion is full of goodness for health. It has antibacterial, anti-inflammatory, antioxidant, and anti-cancer properties.
Apart from its benefits for bodily health, onion contributes to hair health. Onion has also been shown to promote hair growth.
Here, we look at the usefulness of onion hair oil in improving hair thickness and reducing hair loss. We also give a peek into the best onion hair oil for hair growth and thickness.
Table of contents:
- Understanding hair thickness
- How does onion oil promote hair thickness?
- How onion oil prevents hair loss
- Other unexpected benefits of onion oil for the hair
- What to look for in onion oil products?
Understanding hair thickness
The thickness of hair refers to the bulge you feel in a strand when inspected individually. The width of an individual hair strand defines its thickness. Contrary to popular belief, thickness does not equate to the volume of hair.
You may have voluminous hair, but individual strands may be thin. Similarly, you may not have an overall thick growth. Still, each individual strand may be thick.
Hair density is another metric often confused with hair thickness. Density is the count of strands growing across a square inch of the scalp area.

Depending on its thickness, you can categorize your hair into fine, coarse, or medium. Take a strand of hair between your fingers and feel it. If you barely feel it, then it is fine hair. If you can feel it clearly, then it is coarse. Anything in between is medium hair.
Fine, coarse, or medium, your hair texture is not a measure of your hair health. This identification enables you to choose a hairstyle with the least damage.
Quick Fact: Hair texture and thickness depend on multiple genes. But it is the EDAR gene that majorly contributes to hair appearance and growth.
How does onion oil promote hair thickness?
Onion and hair thickness? What is the connection?
The connection is sulfur.
Onions are one of the richest sources of sulfur. This mineral is crucial for the body. It contributes toward the building and healing of DNA. Sulfur also protects cells from risks of cancer and other life-threatening diseases. Adding to the list of benefits is the mineral’s contribution to maintaining healthy skin and ligaments.
Sulfur is an essential nutrient for hair. It makes strands strong and healthy, adds to strand elasticity, and provides scalp nourishment in the form of hydration.
Sulfur has also been known to improve hair and nail conditions, which was examined in a study involving middle-aged women.

Sixty-three participants were administered either a 1g or 3g dose of MSM or methylsulfonylmethane (MSM is abundant in spring onions). Patients ingested MSM in the specified amounts daily.
After four months, results were analyzed based on expert clinical grading and self-assessment by participants. The use of MSM was found to have significant and noticeable benefits in participants.
Faster and better results were observed in participants that consumed a higher dose of MSM.
So, how do onions contribute to improved hair thickness?
As a rich source of sulfur, onion oil promotes hair thickness in the following ways:
- Delivers a positive keratin influence.
The above study concluded that sulfur’s interaction with keratin could be the reason for the mineral’s beneficial results. Keratin protein is the building block for healthy hair.

MSM may contribute to hair and nail health by donating sulfur to keratin. This sulfur donation contributes to stronger molecular bonds between keratin molecules. The strengthened bonds improve hair and nail health.
- Promoting sulfur-containing amino acids.
The positive effects of MSM on hair could be linked to its action of promoting sulfur-containing amino acids. Sulfur can be found in cysteine and methionine amino acids present in the body.
Hair, nails, and skin contain these amino acids. The hair cuticle and cortex, in particular, contain an abundance of cysteine. This amino acid contributes to a strong cuticle, which protects and strengthens hair.
These amino acids keep tissues in these components strong, healthy, and flexible.
- Improved hair cell functions.
Sulfur-containing amino acids improve cell functions by strengthening their ability to detoxify toxic elements, RO species, and free radicals. This function is critical to the maintenance of cell strength and structure.

- Better scalp health.
Sulfur’s ability to keep the scalp hydrated and nourished makes onion oil an excellent base for scalp massaging.
Apart from hydration, the massaging motions improve blood circulation. The gentle and regular movements ensure that nutrients reach all strands. These beneficial actions increase the chances of thicker hair.
How onion oil prevents hair loss
With its abundance of sulfur, Onion oil contributes to healthy hair and scalp. Hair thickness is improved with reduced hair damage and improved hair and strand health.
Onion oil also prevents hair loss by promoting healthy and stronger hair. When hair is healthy, damage due to external factors can be minimized.
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Sulfur-containing onion oil promotes keratin production, strengthening hair in the process.
- Regular use of onion oil ensures a supply of hair-beneficial sulfur to the scalp. Sulfur keeps the scalp hydrated and free of dandruff, promoting scalp health.
Scalp health is crucial as it contributes to hair health. The scalp contains a huge number of hair follicles but is vulnerable to damage as its barrier function is low.
Onion oil promotes a healthy scalp and keeps the scalp strong and hair healthy.
- Anti-bacterial effects of onion oil contribute to a clean scalp. A healthy scalp, in turn, lays the best foundation for thick hair.
- Protects hair from damage. Excessive sun exposure can cause the hair to:
o Go dry and brittle
o Become weak

o Lose shine, color, and texture
o Suffer from a dull and unhealthy look
A haircare routine with onion oil strengthens hair from the inside. Sulfur-rich onion oil enriches strands with keratin and amino acids. As a result, strands become more resistant to damage caused by sun exposure.
Other unexpected benefits of onion oil for the hair
- Improves strand elasticity - Onion oil promotes strand elasticity by promoting keratin interaction.
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Can delay aging effects on hair - With its cell-strengthening functions, scalp-health promotion, and keratin support, onion oil may delay aging effects on hair.
- Acts as a natural conditioner - Onion oil’s hydration capacity makes it a perfect conditioner. Applying it to your strands prevents moisture loss due to shampooing.
- Imparts good texture to hair - Regular use of onion oil keeps strands moisturized, minimizes brittle hair, and reduces split ends. These improvements impart a shiny texture to your hair.
What to look for in onion oil products?
The best onion hair oil for hair growth and thickness gives your strands natural nourishment with keratin and essential amino acids. The best onion oil promotes a scalp environment conducive to healthy hair and strand growth.
It can be overwhelming to choose the best onion hair oil for hair growth and thickness, given the abundance of haircare products. A well-informed approach to product selection increases your chances of choosing the onion oil that works best for your hair.

Choose onion oil that is:
- 100% natural
- Sulfate and paraben-free
- Silicone-free
- Enriched with associate compounds that complement onion oil in strengthening and nourishing hair
You may want to try WOW Skin Science’s Onion Black Seed Hair Oil. It is 100% chemical-free, delivering 100% pure cold-pressed oil. This onion oil is free of silicone, mineral oil, and hexane. With its highly efficient and chemical-free preparation, this onion oil gives the best benefits to your hair.
Make your haircare routine healthier and more advanced with 100% natural haircare products from WOW Skin Science. These products are 100% chemical-free, vegan, cruelty-free, and created from nature.
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