True or false: 6 viral tips

It’s one in the morning and you’re scrolling. A woman pours a bowl of rice water over her lengths. The next video shows a man massaging his scalp with a little spiked gadget. In the third, someone spends four minutes hanging upside down off the bed and swears she gained two centimetres in a month. You wonder which one to try first.

Before you pick, look at what research has actually measured. For some of these hacks there is a study. For others, nothing at all.

Who is giving this advice

In 2023, an American dermatologist, Aaminah Azhar, reviewed the most-watched hair loss remedies on TikTok. She cites an analysis of posts about alopecia: only 4% of those on Instagram and 10% of those on TikTok were created by health professionals¹.

That doesn’t make them all wrong. It means each one needs checking, one by one.

Rosemary oil and castor oil

These are the two big ones, and each has its own article on this site. In short:

Rosemary: promising. It’s one of the few hacks tested on people. In a 2015 trial of 100 people with pattern hair loss, hair counts rose at 6 months, with no significant difference from a 2% minoxidil solution¹. There was no placebo group, and it isn’t clear exactly what kind of oil was used. The details are in our article on rosemary essential oil versus infused oil.

Castor oil: unproven. A 2026 review finds only one effect backed by data: shine. For growth, the idea remains theoretical and needs more research³. We cover it in what we actually know about castor oil.

Rice water

The recipe is everywhere: soak or boil rice, keep the water, pour it over your hair. It’s a long-standing practice in Asia¹.

What has been tested is something else: rice bran extracts, prepared in a lab. In animals, they increase the number of follicles in the growth phase¹. One mouse study even found an effect comparable to a minoxidil solution⁴. But a mouse isn’t a human scalp, and a measured extract isn’t the water you cooked your rice in.

For rice water itself, the dermatologist describes the clinical data as limited¹. The 2025 review of herbal remedies cites no human study of rice bran⁴.

Verdict: unproven. It may leave your lengths feeling nice, but nothing shows it slows hair loss.

Onion juice

This one rests on a real study. In 2002, two Iraqi dermatologists compared raw onion juice with tap water in 38 people: significantly more patients in the onion group saw their hair grow back¹.

The detail the videos skip: those patients had alopecia areata, round bald patches caused by the immune system. That isn’t common pattern hair loss, the kind that thins the crown or the temples over the years. A result in one says nothing about the other. The small number of patients and the lack of any known dose also limit the study⁴.

Even the proposed mechanism raises questions. One hypothesis is that onion irritates the skin, and the irritation distracts the immune reaction that attacks the follicles¹. In other words, any effect would come through irritation. The smell remains the most reported side effect⁴.

Verdict: false for pattern hair loss. For alopecia areata, the study exists, but it is small and old.

Hanging upside down

The “inversion method” promises faster growth: blood rushes to the head, so the roots are supposedly better fed. No study has ever shown this. The French Society of Dermatology (SFD) lists “doing a headstand to bring blood to the scalp” among practices with no proven effect, alongside cutting your hair at the full moon². We look at both myths in our article on common misconceptions.

Verdict: false.

Scalp massage

This is the most interesting hack, because there are two studies, and they don’t say quite the same thing as the SFD.

The first comes from Japan. Nine men with no visible hair loss massaged one side of their scalp with a device, four minutes a day for 24 weeks. The other side served as the control. On the massaged side, average hair thickness went from 0.085 to 0.092 mm. On the other side, nothing changed⁵.

Koyama et al., 2016. The number of hairs did not increase, and the study was partly funded by a company.⁵

The limits are clear. Nine people, all Japanese men, none with hair loss. The number of hairs didn’t go up: it actually dropped temporarily at 12 weeks, which the authors put down to hairs at the end of their cycle falling out early⁵. That’s normal and has an explanation, covered in our article on the hair cycle.

The second study is an online survey of 327 people who had followed a massage programme. 68.9% felt their hair loss had stabilised or their hair was growing back⁶. But everyone rated their own results, only 19% of the people contacted replied, and there was no comparison group. The authors say so themselves: there is no way to separate the effect of massage from the natural course of the hair⁶. Many participants also reported shedding in the early weeks⁶.

The SFD, for its part, lists scalp massage among things that do nothing for hair loss². The two studies don’t really contradict it: neither showed that massage stopped hair loss.

Verdict: plausible, unproven. If you enjoy it, there’s nothing stopping you, as long as you’re gentle.

What the videos leave out

Dr Azhar points to three problems shared by these home recipes¹.

• There is no dose. Boiling rosemary sprigs or putting garlic cloves on your scalp isn’t the same as applying a product with a known strength.
• Some preparations irritate. Fragranced oils, onion and garlic can cause contact dermatitis.
• The biggest cost is lost time: months spent testing hacks before finding out what kind of hair loss it is.

That last point matters. Hair loss that drags on, a widening parting or bald patches deserve a doctor’s opinion: we’ve listed the signs that mean it’s time to see someone. Your doctor can suggest a treatment suited to your type of hair loss.

Testing a hack properly

If you’re set on trying one, treat it like a small study. One at a time, or you’ll never know which one worked. And think in terms of the trials: 24 weeks for massage, 6 months for rosemary⁵¹. Judging after three weeks is judging too soon, especially if some temporary shedding shows up at the start.

The mirror won’t help. Take the same photo every week: same light, same distance, dry hair, parting in the same place.

Calvap does this for you. The app overlays your previous photo as a faint ghost so you can line up the shot exactly, and logs what you apply in your treatment journal. After six months, you put week 1 and week 24 side by side and see whether the hack changed anything for you.