While many people turn to natural remedies for hair care, onion water has emerged as one of the most popular home treatments believed to promote hair growth and reduce hair loss. However, dermatology and beauty experts warn that excessive use may cause scalp irritation and allergic reactions in some individuals, especially those with sensitive skin.

The duration of applying onion water on hair should not exceed about one hour each time, followed by thorough rinsing. Leaving it on for longer periods may lead to scalp dryness and increased irritation.

Despite its potential benefits, onion water may cause:

• Redness and itching of the scalp.
• Skin allergies in people sensitive to onions.
• A strong odor that may linger in the hair for long periods, which can be embarrassing.

If there is a positive response, results may begin to appear after 4 to 6 weeks of regular use, twice a week. However, its effectiveness varies from person to person, and there are no guarantees of the same results for everyone.

Experts recommend the following steps to use onion water safely:

• Peel and chop the onion, then squeeze to extract the water.
• Add a few drops of essential oil such as mint or lavender to reduce the smell.
• Apply the water to the scalp with gentle massage.
• Leave it on for no more than an hour, then wash hair thoroughly with shampoo.
• Test a small amount on a patch of skin before first use to ensure no allergy.

In conclusion, although onion water is famous as a natural remedy to promote hair growth and strengthen follicles, its use may cause some harms, especially when overused or applied incorrectly.