So, What’s the Science?
Red onion juice is rich in quercetin, a powerful flavonoid with antioxidant, anti-inflammatory, and antimicrobial benefits.
According to Dr. Berg, “Onions have the highest amount of quercetin,” making them a potent natural treatment for common scalp concerns — from dandruff to yeast overgrowth — that can slow hair growth or even trigger shedding.
“Quercetin is a powerful antimicrobial, protecting your scalp against overgrowth of yeast, fungus, [and] mold,” says Dr. Berg. “If you also have dandruff or some other problems going on in the scalp, that can help you as well.”
But perhaps even more impressive is quercetin’s ability to support your body’s growth hormones and immune system. “One of the biggest things that quercetin does is it helps suppress this autoimmune attack — the T cell situation,” Dr. Berg explains. In other words, it may calm inflammation that’s secretly sabotaging your strands.
The Sulfur Connection
Onions are also rich in sulfur, a critical building block for keratin, the protein that gives your hair strength and structure. “The sulfur is not necessarily related to hair loss,” he clarifies, “but it is related to the raw material that can help build the main protein in hair, which is called keratin. This keratin is sulfur-based.”
By feeding your scalp with sulfur-rich compounds, you’re essentially giving your follicles the nutrients they need to produce stronger, faster-growing hair. Think of it as follicular fuel.
How to Use It
Dr. Berg recommends juicing organic red onion, applying the liquid directly to your scalp, and letting it sit before washing — twice — with shampoo. The key is consistency: “Apply this twice a week,” he says. “For extreme hair growth.”
While the scent might be intense, the results could be worth it. With regular application, red onion juice may help you grow thicker, fuller, and more resilient hair — naturally. And if you’re dealing with scalp irritation, inflammation, or hair thinning, this DIY remedy might be worth a try.
After all, as Dr. Berg puts it: “Onions are like fertilizer for your hair follicles.”