Bullsh*t or not?

Let’s find out. We’re checking every claim, one by one.

To save you time, we’ve added screenshots of the most important study results.
You’ll find all sources at the bottom of this article.

It sounds like an old wives' tale (and smells like one too), but Red Onion is a heavy hitter in hair science. Here’s why:

✅ Achieved 87% hair regrowth in clinical trials

✅ Extremely high sulfur content (the "beauty mineral" for keratin)

✅ Rich in Quercetin (a powerful antioxidant and anti-inflammatory)

Sounds good — but does it actually work?

What does Red Onion really do for your hair?

Forget the smell for a second. Biologically, onion extract is a nutrient bomb for your scalp.

✔ Provides Dietary Sulfur
Hair is made of keratin, which is held together by disulfide bonds. Onion is rich in sulfur, providing the literal building blocks needed for strong, unbreakable hair strands.

✔ Boosts Circulation (Quercetin)
Red onion is packed with Quercetin. This flavonoid improves blood circulation to the follicles and reduces inflammation, a major cause of hair shedding.

✔ Antimicrobial Action
It fights scalp infections (like dandruff or fungus) that can clog follicles and stunt growth.

What does the science say?

📌 2002 – The "Juice" Study (Alopecia Areata)

This is the study that put onion on the map (Sharquie et al., PubMed). Researchers tested crude onion juice on patients with patchy hair loss (Alopecia Areata).

The result: The numbers were shocking. 86.9% of patients experienced significant hair regrowth after just 6 weeks of twice-daily application.

📌 2025 – The "All-in-One" Mechanic
A massive review published in 2025 (PMC12115063) broke down exactly why onion works so well. It acts as a complete biological toolkit:

Zinc produces essential oils that prevent dandruff, Iron ensures oxygen delivery to the root, and Sulfur physically thickens the hair strand.

Men vs. Women:
The review highlighted that men responded exceptionally well to topical onion treatment, with a 93.7% success rate (compared to 71.4% in women).

With minimal side effects, it is now considered one of the most promising natural alternatives to Minoxidil.

How should you actually use it?

Juicing onions in your kitchen? Please don't.
While effective, the smell is nearly impossible to remove, and raw juice can be irritating to the skin.

What does work?

👉 Odorless Extracts:
Modern science allows us to extract the active Sulfur and Quercetin without the volatile compounds that cause the stink.

👉 Combined Therapy:
Because onion handles the "nutrition" and "inflammation" side of things, it pairs perfectly with stimulating ingredients (like Caffeine) that handle the growth speed.

Verdict: does Red Onion work?

✅ Yes. The 2002 study is one of the most successful natural trials in hair loss history, showing nearly 90% efficacy in specific cases.

Our take?
The results are real, but the DIY method is a social nightmare. You need the benefits of the sulfur and quercetin without smelling like a salad bar.

When used in a properly formulated serum, it is an incredible tool for strengthening weak, brittle hair.

💡 Pro tip: We use a high-potency Red Onion extract in the KÁDESO Grow Serum. We isolated the growth-boosting compounds and removed the smell, so you get the 87% success rate without the tears.

➡️ Want to try it yourself? At least you’ll know you’re using something backed by real science.

Sources

• Sharquie et al. (2002) – Onion juice (Allium cepa L.), a new topical treatment for alopecia areata
  The landmark study showing that topical onion juice resulted in terminal hair regrowth in 86.9% of patients.

• Pharmaceutics (2025) – The Future of Alopecia Treatment: Plant Extracts, Nanocarriers... (PMC12115063)
  Comprehensive review confirming the role of Zinc, Iron, and Sulfur in onion for hair growth and noting a 93.7% success rate in men.