Botanical Hair Ingredients, Explained: What Works, and Why

Cyperus rotundus — nagarmotha in South Asian tradition, rumput teki in Indonesian, and nut grass in English — shows up in hair care with two entirely different jobs attached to its name. The essential oil, distilled from the plant, has been tested as a way to remove hair^[1]. The rhizome, the underground stem of the same plant, extracted a different way, points toward hair growth instead: cell and animal studies show a growth signal^[2], and a separate, well-controlled study found the rhizome extract genuinely calmed inflammation in mouse skin^[3].

The plant is the same but the results were opposites: hair removal from the essential oil, a growth signal from the rhizome. What differs is the part of the plant used and how it's prepared — neither of which a plant's name tells you.

A third variable matters just as much for the ingredients ahead: how much is used, and for how long. Those three questions — part, preparation, dose and duration — carry through the rest of this piece. They're also the honest context for how well any of this is established in the first place. Botanical actives for hair have, on the whole, been studied far less, and in far smaller trials, than mainstream treatments like minoxidil or finasteride. Most of what follows sits at the early or mechanistic end of the evidence scale — here's what that evidence actually shows, ingredient by ingredient, starting with the strongest human result in the group.

Kalonji: real hair growth, in one small trial

In a double-blind, placebo-controlled trial, 20 women with active hair shedding (telogen effluvium) used either a 0.5% black-seed (Nigella sativa) lotion or an identical placebo, daily, for three months. Hair density improved in 9 of 10 women on the active lotion, against 3 of 10 on placebo, and the gain held at six months, while half the placebo group had gotten worse over the same stretch^[4].

The proposed mechanism runs through thymoquinone, black seed's main active compound, which blocks an enzyme (COX-2) and a signal (PGD2) separately implicated in the shrinking of hair follicles over time. That's a plausible, biologically grounded story — the trial measured the outcome, not the mechanism behind it.

On preparation: this was a 0.5% essential-oil lotion applied to the scalp once a day and left on.

This is a small, single, unreplicated study. Real signal, but early.

Fenugreek: strong evidence on split ends, no evidence on growth

Split ends form when the cuticle, hair's protective outer layer, wears away at the tip — the oldest and most weathered part of the strand — from years of friction, heat, sun and handling. Once the cuticle is gone, the cortex underneath is exposed and starts to fray, and once it splits, the two halves can't reattach; a trim above the split is the only real fix, and smoothing products just hide it for a wash or two.

The only human hair trial of fenugreek (methi) — 60 people, two months — tested exactly that problem, and found it worked: split ends improved significantly under a fenugreek seed gel. Hair shedding was also tracked in the same trial, but it was the weakest of four results measured — unsurprising, since having hair loss disqualified someone from taking part in the study in the first place^[5].

The proposed mechanism sits in the seed's mucilage, a galactomannan — a plant sugar that forms a smooth, lubricating film over the hair shaft. Less friction on the strand plausibly means less of the cuticle wear that causes splitting in the first place. Fenugreek's antioxidant and anti-inflammatory content has also been raised as potentially relevant to follicle biology and hair growth, but that half is explicitly proposed rather than shown — even the review that raises it says clinical studies are still needed before it becomes a growth claim^[6].

On preparation: the trial used a standardised 5% extract, assayed to a known concentration of its main compound, applied twice a day and left on for at least twelve hours before washing, for two months.

Rumput Teki: hair removal from the oil, and hair growth signal from the rhizome

Rumput Teki – the essential oil is tested for hair removal, and the rhizome — a different part, prepared differently — points toward growth instead^[1]. The growth side is worth a closer look on its own.

The rhizome's growth signal comes from a single, unreplicated study in cells and animals, and no mechanism for that signal has turned up in any source reviewed here^[2].

The better-controlled finding — genuine anti-inflammatory activity from a rhizome extract — was measured on a mouse's ear, not a scalp, and doesn't itself demonstrate hair growth^[3]. Both sit at the mechanistic end of the evidence scale: real biology worth watching, not yet a demonstrated effect on a living scalp of any species.

Licorice: strong hair growth mechanism evidence in cells, none tested in animals or people

Licorice's main active, 18-β-glycyrrhetinic acid, increased proliferation of the cells that build hair follicles and lowered a signal (TGF-β1) associated with ending the growth phase early. It also blocked 5α-reductase, the enzyme central to pattern hair loss — though weakly, at a concentration in the micromolar range, and with no comparison run against an actual hair-loss drug, so there's no way to say how it measures up against one^[7].

All of that happened in cells in a dish. No animal has been treated with it, and no person has. The paper's own introduction offers a more modest framing than its headline: it argues licorice's practical benefit likely runs through calming inflammation on the scalp generally, which then indirectly supports the conditions hair needs to grow, rather than a direct action on the follicle itself.

The compound tested was supplied by a licorice-extract manufacturer, and a scientist from that company is a co-author on the paper, which states it has no conflict of interest. That doesn't make the finding false. It's a reason to read the headline claim more cautiously than the abstract invites.

A separate, real-world case makes a related point. A licorice shampoo trial followed 47 people for 30 days and found more of them reported their hair shedding got worse (19%) than reported it got better (17%), with roughly one in eight developing dandruff during the trial. The paper's own conclusion was that the product "was safe and showed acceptable results"^[8] — a good reminder to read a study's results table before trusting its summary sentence.

Brahmi: a favourable hair growth result in mice, no human evidence

Brahmi (Bacopa monnieri) has never been tested on a person's scalp. The most recent work is in mice: an extract combined with hyaluronic acid outperformed minoxidil on several growth measures, including follicle area and two markers associated with active hair growth, CD34 and Wnt10b^[9]. The delivery method was unusual — a needle-free device that fires the extract under the skin, rather than anything applied on top of it like an oil or a mask.

It's fair to hold both facts about brahmi together: no human evidence, and a genuinely promising animal signal. A favourable mouse result delivered by injection is a reason to keep watching this ingredient, not a reason to expect the same thing from a bottle applied at home.

Hibiscus: hair regrew in every group, treated or untreated

The one study behind hibiscus for hair growth is a 2003 experiment on shaved rats, comparing leaf extract, flower extract, a plain-oil placebo and an untreated control. Its authors reported the leaf extract came out ahead of the flower extract on regrowth. Buried in the same paper's discussion, though, is a bigger finding: hair grew back on every group tested, including the untreated control and the group that got nothing but plain liquid paraffin. The authors' own explanation was that the regrowth may simply be "the gentle rubbing of the shaved skin while application"^[10] — meaning the act of applying something, any something, may be what did the work, not the hibiscus.

This is the one study hibiscus's reputation for hair growth rests on, and its own authors couldn't rule out that the herb had nothing to do with the result. The leaf-over-flower comparison is still worth knowing, since flower is what most commercial hibiscus hair products use — but it sits inside a study that undercuts its own headline finding.

One note on dosage, across all six: none of the studies above tested more than one concentration, so whether a stronger version works faster or better is genuinely untested. Topical actives don't reliably get better as concentration rises — past a certain point, a higher dose is more likely to irritate the scalp than speed up a result. That's a general principle of how topical actives behave, offered as AYUVAY's own inference rather than a finding from any of these six trials.

Reading the next botanical claim

The same three questions apply to any hair botanical: which part of the plant, prepared how, and for how long or in what amount. A leaf and a flower from the same plant are different ingredients. A 0.5% lotion left on overnight is a different claim from neat oil rinsed out in a shower. And weak evidence usually means an ingredient hasn't been properly tested yet, not that it's been tested and failed — kalonji and fenugreek were both unknowns before the trials above existed.

AYUVAY's piece on what hair oil does and doesn't do covers the same scepticism toward topical growth claims more broadly, and the piece on why hair masks rinse fast goes deeper into contact time specifically — a pre-wash deposit surviving a rinse has only been demonstrated for one ingredient class, silicones. Coconut oil grades are a similar story: a label term that sounds like a specification without one behind it. Whether oiling the scalp itself helps or harms, separate from any one botanical, is covered here. And when the botanical claim is about dandruff rather than growth, the natural anti-dandruff remedies get the same evidence check here.

The bottom line

A plant's name is a starting point, not an answer. What decides whether a botanical does anything for hair is which part of the plant was used, how it was prepared, and how long it stayed on before anyone measured a result. On the current evidence, kalonji and fenugreek have the most to show for it. Licorice and brahmi have real biology behind them and no human proof yet. Rumput teki and hibiscus sit at the early end of the scale — real biology for rumput teki, and a hibiscus study that argues against its own headline finding.

Common questions

Why do some products list so many botanicals?

A long ingredient list often signals marketing insurance, not performance. Spreading a formula across many botanicals means less of each one in the bottle, which dilutes what any single ingredient can do. A long list looks impressive on the label. It doesn't mean the formula performs better.

Do herbal hair ingredients actually work?

Two of the six here, kalonji and fenugreek, have real human trial evidence behind a specific, narrow claim. The rest have real biology or animal signals, not yet tested in people. Asking which part of the plant, prepared how, and for how long usually gets further than asking whether "the herb" works.

Which of these six has the strongest evidence?

Kalonji, on what's held here — a double-blind, placebo-controlled trial in 20 women with active hair shedding^[4]. It's a single, small, unreplicated study, it tested a 0.5% lotion rather than neat oil, and the treated group started with somewhat higher hair density than placebo — a real limitation to weigh against the result. If what's coming out looks like more than ordinary shedding, this piece sorts out what different patterns of hair loss actually mean.

Is "natural" the same as gentle?

Not on this evidence. A licorice shampoo trial recorded more users reporting worse hair shedding than better after 30 days, and its own method listed the same detergents found in conventional shampoos, with the botanical added on top rather than replacing them.

Editorial note

This piece grades six commonly claimed hair-care botanicals against the human, animal and lab evidence that exists for each one. The licorice mechanism study used a compound supplied by a licorice-extract manufacturer, with a company scientist as co-author, on a paper that states no conflict of interest. The kalonji trial, while genuinely double-blind and placebo-controlled, started with a real imbalance between its two groups and was published in a journal with a weak scholarly reputation — the design earns more confidence than the venue does. And the hibiscus study, on its own authors' account, could not rule out that simply applying something to the shaved skin, rather than the herb itself, explains its result.

This article is educational, not medical advice. Ongoing, painful, patchy or unusually rapid hair loss is worth discussing with a dermatologist rather than addressing through ingredients alone.

Source notes

1. [1] Mohammed GF. Topical Cyperus rotundus oil: comparable efficacy to Alexandrite laser photo-epilation — Aesthetic Surgery Journal (2014)
2. [2] Hu Y, et al. The extract of Cyperus rotundus rhizome promotes hair growth — Chinese Journal of Natural Medicines (2026)
3. [3] Rocha FG, et al. Preclinical study of the topical anti-inflammatory activity of Cyperus rotundus L. extract (Cyperaceae) in models of skin inflammation. Journal of Ethnopharmacology 2020;254:112709.
4. [4] Rossi A, et al. Evaluation of a therapeutic alternative for telogen effluvium: a pilot study — Journal of Cosmetic Dermatological Science and Applications (2013)
5. [5] Hajizadeh M, et al. Efficacy of a gel from the seed of Trigonella foenum-graecum L. in preventing trichoptilosis: a randomized placebo-controlled clinical trial. Journal of Mazandaran University of Medical Sciences 2022;32(211):25–36.
6. [6] Bettaieb Rebey I, et al. Fenugreek as a versatile cosmetic ingredient: phytochemical profile, skin–hair benefits and formulation opportunities — Cosmetics (2026)
7. [7] Hagiwara K, et al. 18-β-glycyrrhetinic acid promotes hair growth by stimulating the proliferation of dermal papilla cells and outer root sheath cells, and extends the anagen phase by inhibiting 5α-reductase — Biological and Pharmaceutical Bulletin (2024)
8. [8] Azadbakht M, Monadi T, Esmaeili Z, Chabra A, Tavakoli N. Formulation and evaluation of licorice shampoo in comparison with commercial shampoo — Journal of Pharmacy and Bioallied Sciences (2018)
9. [9] Wu YC, Lin YP, Chang CY, et al. Enhanced hair growth through transdermal delivery of Bacopa monnieri extract using a needle-free supersonic atomizer — Journal of Medical and Biological Engineering (2025)
10. [10] Adhirajan N, Ravi Kumar T, Shanmugasundaram N, Babu M. In vivo and in vitro evaluation of hair growth potential of Hibiscus rosa-sinensis Linn — Journal of Ethnopharmacology (2003)