You might be surprised to hear the humble onion is used by thousands of people around the world to promote hair growth. This versatile staple, which has been cultivated for over 5,000 years, is believed by many to not only stop hair loss but even promote its regrowth.
So does it work?
What’s In Onion Juice That Helps Hair?
High sulfur content may directly build hair keratin
The key ingredient in onion juice believed to remedy hair loss is sulfur. Onions are 89% water, but they contain high levels of sulfur. Garlic, a species of the same Allium onion genus, is also sulfur-rich and also mooted as a cure for hair loss, although less well known as onion.
It’s believed that supplementing the levels of sulfur in your body can contribute to hair growth. Sulfur is stored in the body as an organic compound called methylsulfonylmethane (MSM). The compound breaks down, releasing sulfur, which helps grow hair, bone and nails.
To learn more see MSM for Hair Growth: A Complete Guide.
But the substance which gives skin, nails and hair increased resilience and strength is keratin.
Keratin is composed of strong protein fibers which help protect epithelial cells. The amino acids which make up these keratin proteins contain high levels of sulfur.
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Anti-bacterial properties may protect scalp from infection
A study has also proven the antibacterial properties of onion juice. Even after 48 hours, extracts of onion at room temperature were shown to have an antibacterial effect on common bacterial strains. Hair needs a healthy scalp and follicles to grow strongly, so this ability to fight infections may have a positive effect on hair growth.
High antioxidant content may protect scalp and follicles from free radicals
A further study has revealed the onion to be one of the richest sources of dietary flavonoids. These antioxidants neutralize free radicals, the molecules that lead to premature ageing. Free radicals may have a negative effect on hair follicle development, reducing hair regrowth.
Reducing scalp inflammation
It is believed that scalp inflammation is one of the key causes of male pattern hair loss. Fortunately, the sulfur found in onion works as an anti-inflammatory agent, further helping to create a healthy scalp environment.
For people with a sulfur deficiency, increasing sulfur in the diet will almost certainly help regenerate hair follicles and promote hair growth.
The studies cited show that onion juice contains substances which are powerful weapons for treating hair loss. We know as well that onion is a great source of minerals, including potassium, germanium, calcium and manganese. Onion is also rich in vitamins B6 and C. These all help to nourish the scalp and combat hair loss.
Have there been any studies which actually prove the effectiveness of onion juice in treating hair loss? There has been only one so far, carried out in Baghdad Teaching Hospital, Iraq.
Study Shows Onion Juice Reverses Alopecia Areata
The study found that there was some regrowth of terminal coarse hairs after only two weeks
In June 2002, the Journal of Dermatology published a study exploring how effective onion juice is in treating alopecia areata. It’s important to note that alopecia areata is a different hair loss to the much more common male-pattern baldness.
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Alopecia areata is a patchy hair loss condition which can occur on areas of the body outside the scalp. It can affect people of all age and ethnic groups, as well as both sexes. It occurs when the immune system attacks the body’s hair follicles, suppressing hair growth. This results in small patches of hair loss, which are usually not permanent.
Male-pattern baldness is a hereditary condition though which is permanent, and results in complete loss of hair around the crown of the head and the temples. Known also as androgenetic alopecia, predisposition depends on levels of the male sex hormone, DHT and levels of the stress hormone cortisol — as well as several other factors.
In the study, participants were divided into two groups. 23 patients aged between five and 42 made up the first group, 16 males and seven females. This group was asked to apply an onion juice treatment twice daily for two months. Eight males and seven females, aged between three and 35 years, formed the second, control group. They applied tap water to their scalps at the same intervals as the first group.
The study found that there was some regrowth of terminal coarse hairs after only two weeks in some of the group using onion juice. After four weeks, hair regrowth was observed in 17 patients, almost three quarters of the total group. Finally after six weeks, hair regrowth was observed in 20 patients, almost 90% of the total.
Hair regrowth in the control group using tap water was restricted to just two patients after eight weeks, one male and one female. Perhaps surprisingly for the group using onion juice, males outperformed the females in hair regrowth. Only one of the 16 males in the group failed to regrow hair; while two out of 7 females failed to do so. The results of this study suggest that crude onion juice is much more effective in treating patchy alopecia areata than tap water.
While this is the only known study to have been carried out to show the effectiveness of onion juice on hair loss, the results are very encouraging. It should be remembered though that the type of hair loss suffered by the study’s participants was the transitory alopecia areata. For male-pattern baldness, where DHT is the main offender, no such encouraging research results have been forthcoming. Still, onion juice can help to reduce both follicle inflammation and the levels of DHT found on the scalp. This means that sulfur-rich onion juice might at least slow the effects of male-pattern baldness, which will be a comfort to many even if it’s not a cure.