Buckle up. Our insatiable thirst for natural cures and viral hacks meets a very shaky study.
Should you be rubbing an onion on your head? No, definitely not, it’s a bad idea. Read on to find out where this myth came from and why this hack is bad news for your scalp. Image by stocking for Freepik.
Yet another sure fire ‘natural’ hair growth remedy is making the rounds, and this one at least earns its ‘kitchen sink’ moniker. Can onion juice really beat minoxidil for hair growth? Are you missing out on a so-called miracle cure? As a hair restoration surgeon, I’m all for inexpensive options that truly help people reach their hair goals, and I get that the lure of a cheap, do it yourself at home cure that promises to beat medical therapies is nigh irresistible. The millions of views being racked up on videos like this one (which I debunked) and many more shows that there’s an appetite.
Unfortunately, this one is bunk and depending on what protocol you try, it could do some serious harm to your scalp.
As it always seems with these naturally derived viral hacks, there’s a grain of research that’s been misinterpreted and woefully misused. Let’s take a look at what the research actually says about onion’s potential and separate what’s real from what’s… well, tear-inducing.
Everything Leads Back to Rosemary Oil
Our collective natural appetite for natural hair treatments seems to have really kicked off a few years back when rosemary oil became all the DIY rage, stemming from a single small 2015 study that compared rosemary oil to 2% topical minoxidil for hair growth efficacy. Both tested groups showed minimal change with large variability and poor documentation. Even the “after” photos were inconsistent. The authors concluded “as effective,” but a more honest reading of their results would have been “equally ineffective in this trial.” That tells you very little about rosemary’s real-world benefit and ignores the much larger body of evidence supporting minoxidil at 5%. Why haven’t we seen a follow-up study? Usually when there isn’t follow-up on preliminary study like this, it’s because the research hit a dead end.
So where does that leave us with regards to onions?
Rosemary oil is wonderful in cooking, not so much applied on your head. Image by Freepik.
The Onion Studies Everyone Cites… and What it Actually Says
There is one clinical study out of Baghdad from 2002, that looked at the effectiveness of topical onion juice to treat alopecia areata (AA), autoimmune-triggered patchy hair loss, not androgenetic alopecia (AGA). This is the most represented aspect of the study, as almost everyone online is claiming onion juice as effective in treating male/female patterned hair loss, the most common form of hair loss that people are often looking for help dealing with. It’s not. They’re very different conditions.
And, even if you were considering using onion juice to treat alopecia areata, the study was inconclusive as it had some design flaws. The study was single-blinded, meaning patients knew what they were using (onion vs. water), which always invites a placebo bias; people want the treatment to work, so they see it working. Half the onion group also dropped out, but we don’t know why. Was it because they saw no effect? If so, that drastically inflates the claims of “87% regrowth” at 8 weeks. And as to that regrowth? rigorous metrics weren’t used to quantify results, and alopecia areata tends to resolve spontaneously, which muddies the results further.
At best, the paper suggests that onion juice might irritate the scalp enough to nudge regrowth, like squaric acid does to redirect autoimmunity. That will not work on androgenetic alopecia, as it has nothing to do with DHT regulation.
Quercetin: The Bioflavonoid with Anti-Inflammatory Properties
People also like the idea of onion as a treatment for hair loss because of the sulfur compounds and antioxidants present in the juice. In theory, these could reduce inflammation, increase blood flow and circulation around the hair follicle. But so do a lot of things, many of which are better researched (minoxidil, caffeine).
Quercetin is a bioflavonoid found in many red coloured berries, fruits and vegetables. Red onions, red wine, black tea, apples, and kale are all examples of foods high in this compound. Keep in mind, this was investigated as a potential dietary supplement, not as a topical compound. Image by pvproductions for Freepik.
Quercetin is one of these antioxidants (that onions are high in) where there is some evidence that isolated preparations (NOT onion juice) can elicit hair growth in mice with patchy alopecia areata, not androgenetic alopecia. A paper out of Miami in 2011 showed potential, but as an injected compound, not applied topically. Their interest was for its potential as a dietary supplement. It’s certainly interesting as a future supplementary treatment for alopecia areata, but it needs a lot more research before it could be recommended.
Irritation is the Name on the Game
I mentioned earlier that one of the potential uses for onion compounds is their (theoretical) potential to distract the immune system through irritation. The problem is that these compounds can be very irritating and if not diluted and carefully dosed, can easily cause contact dermatitis and potentially chemical-like burns (sulfur compounds can denature proteins causing it to blister).
What About “Supercharging” Onion Juice by Fermenting It?
Please Don’t. Fermentation is controlled spoilage. Unlike kimchi or sauerkraut, onion juice doesn’t offer a protective environment for safe home fermentation. You’re inviting bacterial and fungal contamination (think E. coli, Salmonella, Clostridium species) and producing an unknown chemical cocktail (alcohols, enzymes, other assorted byproducts) Leaving that on your scalp for an hour? As a clinician: hard pass.
What Actually Works for Most People (And How to Combine It)
The first step is to determine what form of hair loss you have. Hair loss treatments are not interchangeable. The good ones address the underlying biological cause which need to be specific.
When it comes to the most common form of hair loss, androgenetic alopecia, you need to think in three lanes:
1. Prevention (DHT control)
- Finasteride/dutasteride (oral or topical, when appropriate) to slow follicle miniaturization. This is the foundation for many men and some women.
2. Stimulation (thickening)
-
Minoxidil (topical 5% or oral low-dose in selected patients)
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Microneedling (done correctly)
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PRP (well-studied) or PRF (promising but younger evidence) as boosters
- Appropriate supplemental adjuncts like saw palmetto, pumpkin seed oil, curcumin, and caffeine which have reasonable evidence to support their use and safety.
3. Augmentation (redistribution)
- Hair transplant when areas are too thin or bare for medical therapy alone.
Inexpensive Prescription Hair Loss Medication Delivered To Your Door.
How to Vet “Miracle Cures” (My quick checklist)
With the influencer age upon us, quick fix miracle cures are here to stay. Read on for how to evaluate whether you should be wasting precious produce. Image by drobotdean for Freepik.
The trend of ‘miracle cures’ is unfortunately only proliferating. Social media (and our appetite for it) just makes it too appealing to content creators trying to go viral. As such, the next time you’re faced with a treatment that looks too good to be true, go through this checklist before you buy in:
- Condition match: Does the study match your diagnosis (AGA vs AA vs telogen effluvium)?
- Study quality: Randomized? Blinded? Adequately powered? Objective measurements?
- Reproducibility: One small study from decades ago or multiple modern trials?
- Mechanism: Does it make biological sense for your type of hair loss?
- Risk vs. reward: Any safety issues (contamination, irritation, limited safety profile)?
- Cost & consistency: Can you realistically stick with it for 6–12+ months?
If a remedy fails this checklist, it doesn’t belong in your primary plan.
Bottom Line
Until there’s a greater body of research showing effectiveness and ironing out treatment protocols, onions deserve a pass in favor of more well-established treatments.
If you’re looking for safe, effective adjuncts to add to your hair routine, you need go no further than our Feel Confident Root Defense system. All our hair products are science-informed, research backed, designed for daily use, and not kitchen concoctions
Considering exploring your hair transplant options? Book a consultation with me so we can sketch a clean, evidence-based plan that makes sense for you—no onions required.
