Ayurvedic hair care · Traditional knowledge
Unlike greying, hair loss and flaking, this one has no classical disease name. What the texts offer instead is Kapha.
There is no Sanskrit word at the top of this page, because the texts do not give one.
Greying is Palitya. Gradual hair loss is Khalitya. A flaking scalp is Darunaka. Each has a name, a chapter, a described sequence and a prescribed treatment. An oily scalp has none of those.
That absence is the most interesting thing on this page, and it is where we are going to start. In the classical account, a scalp that produces plenty of sebum is a description of a person before it is a complaint about one.
The terms used on this page
One
The classical literature is not shy about naming hair and scalp disorders. It has a term for gradual hair loss and a separate one for patchy loss. It distinguishes greying in its time from greying before it. It is a literature that names things.
| Condition | Classical name | Where it is discussed |
|---|---|---|
| Greying | Palitya | Kshudra Roga; its own Samprapti and Chikitsa |
| Gradual hair loss | Khalitya | Kshudra Roga or Shiroroga; four types by dosha |
| Patchy hair loss | Indralupta | Rakta Pradoshaja Vikara |
| Flaking scalp | Darunaka | Kshudra Roga or Shiroroga; five lakshanas |
| Oily scalp | — | No disease category. It appears only as a description |
Oiliness does appear in the texts. But it appears in two places, and neither of them is a chapter on disease.
First
A greasy scalp is described among the characteristics of Shleshmala Purusha, the Kapha-predominant person. Prakriti is fixed at birth and is not a disorder. The texts describe constitutions; they do not prescribe against them.
Second
Where oiliness is treated as pathological, it is as a lakshana — a sign — within Darunaka, in its Kapha-predominant form. The disorder there is the flaking and itching. The greasiness is the accompanying character of it, not the thing itself.
What follows from an absence
A scalp that produces sebum is doing what a scalp does. Every pore has a gland; the oil is what keeps skin and hair from drying out. A system that named greying, thinning, patchy loss and flaking as disorders, and did not name this, was making a judgement about it.
We are not claiming the classical authors were right about the physiology. We are pointing out where they drew a line, because they drew it in a place the hair care market has spent decades erasing.
The texts describe hair by constitution, and the descriptions are not evenly flattering. Vata-predominant hair is given as dry and sparse. Pitta-predominant hair as prone to early greying and to balding.
Shleshmala Purusha
Thick. Curly. Strong.
That is the classical description of Kapha-predominant hair, and it is the most favourable description of hair in the literature. The same constitution that produces a scalp needing washing more often produces the hair the texts praise.
If you have spent years treating your scalp as a problem to be corrected, it is worth sitting with the possibility that what you have is a constitution, and that the tradition thought rather well of it.
What the texts do offer, where the balance has actually shifted, is a principle for how to respond. That is the next section.
Two
Where the balance has genuinely shifted — where Kapha has increased beyond its measure rather than simply being someone’s constitution — the classical response is not a substance that targets oil. It is a set of qualities opposite to the ones in excess.
The principle has a name: Samanya Vishesha Siddhanta. Like increases like; opposites decrease. Applied to treatment it becomes Viparita Guna Chikitsa — treatment by contrary quality. It is one of the organising ideas of the whole system, and it is why Ayurvedic reasoning about substances runs through qualities rather than through targets.
A dosha is described by its gunas — its qualities. Charaka gives Kapha’s as follows, and reading them, an oily scalp is not a coincidence.
| Kapha guna | Meaning | Opposite |
|---|---|---|
| Snigdha | Oily, unctuous | Ruksha — dry |
| Guru | Heavy | Laghu — light |
| Manda | Slow, dull | Tikshna — sharp, penetrating |
| Sthira | Stable, immobile | Chala — mobile |
| Shita | Cold | Ushna — hot |
| Picchila | Sticky, slimy | Vishada — clear, non-slimy |
Notice what kind of answer this is
The question the system asks is not what removes sebum. It is which qualities are in excess, and which qualities oppose them.
That is a different sort of reasoning from a modern formulation, which identifies a target and acts on it. Neither is obviously the better way to think. But they are not the same way, and a page that presented Ayurvedic herbs as though they worked by targeting sebum would be describing modern pharmacology in Sanskrit.
The six rasas — tastes — each act on the doshas, and three of them reduce Kapha.
| Rasa | Taste | Effect on Kapha |
|---|---|---|
| Katu | Pungent | Reduces |
| Tikta | Bitter | Reduces |
| Kashaya | Astringent | Reduces |
| Madhura | Sweet | Increases |
| Amla | Sour | Increases |
| Lavana | Salty | Increases |
A distinction we have to hold on to
Our own measurements put shikakai at pH 2.1 to 3.0 — strongly acidic. It would be easy, and wrong, to reach for Amla rasa as the Sanskrit for that.
Amla means the sour taste, and in this pharmacology a taste is a category with actions attached to it: sour increases Pitta and Kapha, decreases Vata, and is described as heating. pH is a measurement of hydrogen ion activity in a solution. They are not the same kind of thing, and one is not the modern name for the other.
A substance can read low on a meter without being Amla in the classical sense, and the classical sources describe shikakai as astringent rather than sour. We publish the pH because it is a number you can check. We are not going to dress it up in Sanskrit.
If you follow the logic rather than the marketing, the classical response to an excess of Kapha at the scalp is Ruksha, Laghu, Tikshna, Ushna — dry, light, sharp, warming — and the astringent and bitter tastes.
And it would not be confined to the scalp. Kapha increase is described as systemic, provoked by diet and by habit: sweet, sour and salty foods, heavy and oily food, cold food and drink, daytime sleeping, and a lack of movement. Nidana Parivarjana comes first here as everywhere.
We are describing a system of reasoning, not giving you a regimen. Assessing whether Kapha is genuinely increased, as against simply being your constitution, is what a qualified Ayurvedic physician does — and the distinction matters, because the treatment for an excess and the treatment for a constitution are not the same thing. One of them is nothing.
Which leaves the question this page is really being read for: what actually happens when you wash a greasy scalp with a plant. That has an answer, and it is chemistry rather than doctrine.
Three
This is the part of the page we can be definite about. Reetha and shikakai genuinely clean, and the mechanism is ordinary surfactant chemistry rather than anything requiring a doctrine to explain.
A correction
Until recently this page said: “Saponins are alkaloids that foam like soap.”
Saponins are not alkaloids. An alkaloid is a nitrogen-containing basic compound — caffeine, morphine, nicotine. A saponin is a glycoside: a non-sugar core with one or more sugar chains attached. The two categories have nothing in common beyond both being plant compounds.
We have corrected it here rather than quietly. Our pages on reetha and shikakai describe them correctly as triterpenoid saponins.
That architecture is the whole mechanism, and it is the same one every soap and shampoo on the shelf uses.
What differs between one surfactant and another is what the water-loving end is made of — and there the difference between a plant saponin and a sulfate is worth knowing.
A difference that never appears on packaging
Reetha’s sapindosides carry no electrical charge. Sulfates carry a negative one — and hair’s own surface is negatively charged at washing pH.
That interaction is part of why hair can come out of a sulfate wash feeling squeaky and rough. A non-ionic surfactant does not have that particular argument with the fibre. This is physical chemistry rather than a health claim, and it is not in dispute.
Lather is what happens when a surfactant traps air. Cleaning is what happens when it surrounds oil. They are different properties, and neither predicts the other.
Dishwasher detergents are deliberately engineered not to foam, because foam interferes with the spray arm, and they clean perfectly well. Shampoo foams heavily because people expect it to, not because the foam is doing the work.
A second correction
This page also said that reetha’s saponin “helps create foam” and that shikakai “lathers mildly”. The first is misleading and the second is generous.
Both powders produce a thin, short-lived foam at best. If you are coming from a conventional shampoo, they will feel as though they are not working, and that impression is the most common reason people give up on them. It is worth knowing before rather than after.
| Reading | Relative to hair | |
|---|---|---|
| Shikakai | pH 2.1–3.0 | Well below |
| Reetha | pH 4.54–4.90 | Inside the range |
| Hair’s own surface | pH 4.5–5.5 | — |
Reetha lands inside hair’s own range with nothing added to adjust it, which is unusual for a wash. Soap sits around pH 9 or 10, and our own shampoo bar reads 9.35.
Shikakai sits well below, and its acidity is buffered — dilute it to half strength and the reading barely moves. Acidic conditions keep cuticle scales lying flat against the shaft, which is most of what we perceive as smoothness, and it is why shikakai washes and softens in the same step.
Handheld meter, calibrated against pH 4.00 and 7.00 buffers, on a suspension of milled plant rather than a clear solution. Water hardness will move it. We publish these because they are numbers you can check with an inexpensive meter, and because we have not found anyone else publishing any.
Removing oil that is on the hair is not the same as changing how much your scalp makes. Reetha and shikakai take away sebum that is already there. We have seen no evidence that they, or any plant powder, act on the sebaceous glands themselves, and we do not claim it.
Sebum production is described in modern physiology as under hormonal control. If your scalp produces a lot of oil, it will still be producing a lot of oil after you wash it. The washing is worth doing; it is just not doing that.
And an argument we are not going to use
You will read, constantly, that harsh shampoos strip the scalp and cause it to over-produce oil in response — and that a gentler wash therefore breaks the cycle. It is a good argument for selling what we sell.
We are not going to make it. The evidence for rebound sebum production after washing is weak and contested, and the sebaceous gland is not generally understood to respond that way on that timescale. We would need better grounds than a plausible story before putting it on a page.
If it turns out to be well supported, we will say so and add it. Until then, declining to use an argument that favours us seems like the least we can do on a page that has just corrected two of its own errors.
Four
Two powders, and the choice between them is not about which is stronger. It is about what is left behind.
| Reetha | Shikakai | |
|---|---|---|
| Botanical | Sapindus mukorossi | Acacia concinna, also listed as Senegalia rugata |
| What it does | Washes, and nothing else | Washes and softens in one step |
| Our pH reading | 4.54–4.90 — inside hair’s range | 2.1–3.0 — well below it |
| At 1:3 with water | A pourable liquid | A pourable liquid |
| On the hair | 2–3 minutes, then rinse | 2–3 minutes. Do not leave it longer |
Neither is a stronger cleanser than the other in any way we have measured. They can also be used together, and traditionally often were. Full amounts and method are on the reetha and shikakai pages.
One — the eyes
In our own experience reetha stings the eye noticeably more than ordinary soap does. Being a plant does not make a molecule gentle on the cornea. And because this is milled fruit rather than a dissolved detergent, fine particles can lodge and keep working after the water is gone.
Tilt your head back, keep your eyes closed while the wash is on, and if any gets in, flush with plenty of cool running water — well past the point it stops hurting. Do not rub.
Two — shikakai is acidic, and it is a wash
At pH 2.1 to 3.0 it is in the region of lemon juice, and diluting it will not soften that — the acidity is buffered, and halving the strength barely moves the reading. Use less powder or less time instead. Do not leave it on as a mask, and avoid it on broken or inflamed skin.
Three — after colouring
Do not wash with either powder in the 72 hours after a plant colour. Henna and indigo keep developing for up to three days, and a surfactant inside that window will carry some of the result away with it.
This is a question about your scalp rather than about the herb. Nothing accumulates and nothing needs to build up on a schedule, so there is no minimum frequency for these to work and no benefit to a fixed routine.
A Kapha-predominant scalp may want washing more often than a Vata-predominant one. That is the sensible reading of the constitutional material in section one, and it is as far as we will take it — the tradition assesses a person before it prescribes a frequency, and we cannot assess anyone from here.
Gathered in one place, because we have said no to a number of things and it is worth being able to see them together.
What is left after all of that is still worth having: two plants that clean hair through their own surfactants, one of which lands inside hair’s natural pH range without anything added to put it there.
That is a smaller claim than the page used to make. It is also one we can stand behind entirely.
We are not Sanskritists, and we have not read the Samhitas in the original. The material on Kapha’s qualities, the six rasas and the principle of treatment by opposites is standard Ayurvedic pharmacology, drawn from reviews and textbooks rather than from verse we have checked ourselves. We have not cited chapter and verse here because we cannot honestly do so.
The pH figures are our own, taken on a handheld meter calibrated against pH 4.00 and 7.00 buffers. The surfactant chemistry is not in dispute and is not specific to these plants.
Referenced
If we have any of this wrong, we would like to know. Write to laboratory@radicousa.com. This page has corrected three of its own statements — on saponins being alkaloids, on foam, and on vitamins — and we would rather add a fourth correction than leave one standing.
This page describes a traditional system of medicine for general interest, alongside surfactant chemistry. It is not medical advice, not a diagnosis, and not a treatment claim for any Radico product. Radico makes cosmetics; none of our products is intended to diagnose, treat, cure or prevent any condition. A scalp that is greasy together with redness, yellowish scale or soreness, or that has changed noticeably and quickly, should be assessed by a doctor — seborrhoeic dermatitis and hormonal changes both present that way, and neither is a washing problem.
