How does onion juice help hair growth? Receding hair line, hair loss and thinning on a young man. Onions have many potential health benefits. Onion juice may help to encourage the growth of thick, healthy hair. Nutrients in the onion juice applied to the hair may nourish the hair follicles, which might increase volume, shine, and improve hair strength. The extra nutrition may also minimize breakages and thinning. Dietary sulfur One theory on how onion juice can help hair regrowth is that onions contain dietary sulfur.
Sulfur is one of the most common minerals in the body. It is needed for adequate production of enzymes and proteins. Sulfur is also found in keratin, which is one of the components of hair.
The sulfur in onion juice may provide the hair with the nourishment it needs to grow. It may also increase the growing phase of the hair. .


  Onion Juice: An Effective Home Remedy for Combating Alopecia.
Abstract : Alopecia areata is a patchy, non-scarring hair loss condition. Any hair-bearing surface may be involved, and different modalities of treatment have been used to induce hair regrowth. This study was designed to test the effectiveness of topical crude onion juice in the treatment of patchy alopecia areata in comparison with tap water. The patients were divided into two groups. The first group [onion juice treated] consisted of 23 patients, 16 males (69.5%) and 7 females (30.5%). Their ages ranged between 5-42 years with a mean of 22.7 years. The second group [control; tap-water-treated] consisted of 15 patients, 8 males (53.3%) and 7 females (46.6%). Their ages ranged between 3-35 years with a mean of 18.3 years. The two groups were advised to apply the treatment twice daily for two months. Re-growth of terminal coarse hairs started after two weeks of treatment with crude onion juice. At four weeks, hair re-growth was seen in 17 patients (73.9%), and, at six weeks, the hair re-growth was observed in 20 patients (86.9%) and was significantly higher among males (93.7%) compared to females (71.4%) P<0.0001. In the tap-water treated-control group, hair re-growth was apparent in only 2 patients (13%) at 8 weeks of treatment with no sex difference. The present study showed that the use of crude onion juice gave significantly higher results with regard to hair re-growth than did tap water (P<0.0001), and that it can be an effective topical therapy for patchy alopecia areata.


  The influence of sulfur and hair growth on stable isotope diet estimates
Abstract: Stable isotope ratios of grizzly bear (Ursus arctos) guard hair collected from bears on the lower Stikine River, British Columbia (BC) were analyzed to: 1) test whether measuring δ34S values improved the precision of the salmon (Oncorhynchus spp.) diet fraction estimate relative to δ15N as is conventionally done, 2) investigate whether measuring δ34S values improves the separation of diet contributions of moose (Alces alces), marmot (Marmota caligata), and mountain goat (Oreamnos americanus) and, 3) examine the relationship between collection date and length of hair and stable isotope values. Variation in isotope signatures among hair samples from the same bear and year were not trivial. The addition of δ34S values to mixing models used to estimate diet fractions generated small improvement in the precision of salmon and terrestrial prey diet fractions. Although the δ34S value for salmon is precise and appears general among species and areas, sulfur ratios were strongly correlated with nitrogen ratios and therefore added little new information to the mixing model regarding the consumption of salmon. Mean δ34S values for the three terrestrial herbivores of interest were similar and imprecise, so these data also added little new information to the mixing model. The addition of sulfur data did confirm that at least some bears in this system ate marmots during summer and fall. We show that there are bears with short hair that assimilate >20% salmon in their diet and bears with longer hair that eat no salmon living within a few kilometers of one another in a coastal ecosystem. Grizzly bears are thought to re-grow hair between June and October however our analysis of sectioned hair suggested at least some hairs begin growing in July or August, not June and, that hair of wild bears may grow faster than observed in captive bears. Our hair samples may have been from the year of sampling or the previous year because samples were collected in summer when bears were growing new hair. The salmon diet fraction increased with later hair collection dates, as expected if samples were from the year of sampling because salmon began to arrive in mid-summer. Bears that ate salmon had shorter hair and δ15N and δ34S values declined with hair length, also suggesting some hair samples were grown the year of sampling. To be sure to capture an entire hair growth period, samples must be collected in late fall. Early spring samples are also likely to be from the previous year but the date when hair begins to grow appears to vary. Choosing the longest hair available should increase the chance the hair was grown during the previous year and, maximize the period for which diet is measured.


 


Onion Juice (Allium cepa L.), A New Topical Treatment for Alopecia Areata
Abstract Alopecia areata is a patchy, non‐scarring hair loss condition. Any hair‐bearing surface may be involved, and different modalities of treatment have been used to induce hair re‐growth. This study was designed to test the effectiveness of topical crude onion juice in the treatment of patchy alopecia areata in comparison with tap water. The patients were divided into two groups. The first group [onion‐juice treated] consisted of 23 patients, 16 males (69.5%) and 7 females (30.5%). Their ages ranged between 5–42 years with a mean of 22.7 years. The second group [control; tap‐water‐treated] consisted of 15 patients, 8 males (53.3%) and 7 females (46.6%). Their ages ranged between 3–35 years with a mean of 18.3 years. The two groups were advised to apply the treatment twice daily for two months. Re‐growth of terminal coarse hairs started after two weeks of treatment with crude onion juice. At four weeks, hair re‐growth was seen in 17 patients (73.9%), and, at six weeks, the hair re‐growth was observed in 20 patients (86.9%) and was significantly higher among males (93.7%) compared to females (71.4%) P<0.0001. In the tap‐water treated‐control group, hair re‐growth was apparent in only 2 patients (13%) at 8 weeks of treatment with no sex difference. The present study showed that the use of crude onion juice gave significantly higher results with regard to hair re‐growth than did tap water (P<0.0001), and that it can be an effective topical therapy for patchy alopecia areata.