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The scalp: dandruff, itch and what the follicle needs from within

Count the sebaceous glands in a square centimetre of scalp and you land somewhere between 400 and 900. In the palm of the hand there are none at all. That one difference explains most of how the scalp behaves, and almost none of it is visible in a mirror.

Hair care in Sweden is overwhelmingly a conversation about the hair shaft: how it looks, how it breaks, what you put on it. The shaft is dead keratin, with no blood supply, no metabolism and no capacity to repair itself. The living part of the system is the skin the shaft grows out of, and the follicle buried inside that skin. This article is about that part: what the scalp is, what dandruff and itch mean, and what the follicle needs from within. That last question is where a food supplement comes in, and it is why Health Royals built Hair Beautification around the follicle rather than the shaft. We have written separately about the biology of the hair fibre, so here we stay below the surface.

The short version

• The hair shaft is dead keratin. The living part of the system is the scalp: skin carrying 400 to 900 sebaceous glands per square centimetre, a microbial community of its own, and follicles that sustain one of the highest rates of cell division in the body.

• Dandruff is the mild end of seborrhoeic dermatitis, and what has trial data behind it is a shampoo containing ketoconazole or ciclopirox, used on the schedule on the box. Itch that persists, or hair that comes out in patches, is a question for a doctor.

• The follicle is supplied from within, through the blood, and that is the level a food supplement works at. Hair Beautification carries Keranat® millet seed extract at 300 mg per daily dose, the dose in the ingredient's placebo-controlled study, with biotin, zinc and vitamin B6. Biotin and zinc contribute to the maintenance of normal hair.

Health Royals Hair Beautification, hair supplement with Keranat millet extract, biotin and zinc

Hair from within at Health Royals

Hair Beautification is built around Keranat® millet seed extract from Robertet at 300 mg per daily dose, the dose used in the ingredient's randomised, double-blind, placebo-controlled twelve-week study on women, with 50 µg biotin, 1.4 mg vitamin B6 and 10 mg zinc as zinc citrate. Biotin contributes to the maintenance of normal hair and normal skin. Zinc contributes to the maintenance of normal hair, normal skin and normal nails. Vitamin B6 contributes to normal protein metabolism. It is a food supplement for the follicle from within.

See Hair Beautification, hair vitamins with millet extract

What makes the scalp different from the skin on the rest of the body?

Density, mostly. The scalp carries more sebaceous glands, more hair follicles and more microbial life per square centimetre than almost any other site on the body.

The gland and the follicle are not separate structures. Together they form the pilosebaceous unit: the gland empties through a duct into the follicle, and its secretion travels up the follicular canal to reach the surface. A 2025 review in Cells puts sebaceous gland density on the scalp and forehead at 400 to 900 glands per square centimetre, with the palms and soles carrying none at all.

What those glands make is not simply oil. Sebum is a mixture of triglycerides, wax esters, squalene, cholesterol and free fatty acids, and squalene and wax esters are produced nowhere else in human tissue.

The result is a very specific environment: lipid rich, humid, mildly acidic, and perforated by tens of thousands of follicular openings. A 2026 review in Molecules calls this a specialised ecological niche that shapes a scalp microbial community distinct from skin elsewhere, carrying roughly 10,000 to 100,000 bacterial cells per square centimetre alongside a fungal population dominated by two species of Malassezia.

Underneath all of that sits the follicle, with its own blood supply. The surface is reached with a shampoo. The follicle is reached with what the blood carries, and that distinction runs through the rest of this article.

Why can a scalp be dry and flaking while the hair still goes greasy?

Because oiliness and barrier function are two separate things, and a scalp can have plenty of the first while the second is under strain.

Dryness on the scalp is usually not a shortage of sebum. It is a stratum corneum losing water faster than it should and shedding in visible clumps rather than invisible single cells. In seborrhoeic dermatitis, a 2025 narrative review in Biomedicines reports altered keratin expression and reduced ceramides and sphingolipids in affected skin. That is a barrier question rather than a moisture question, and a conditioner works on the fibre, not on the skin.

The Molecules review traces the same cascade at molecular level. Irritant lipid breakdown products activate inflammatory signalling, keratins K6, K16 and K17 are overexpressed, filaggrin is downregulated, and the barrier weakens further, which makes the next round easier. The authors describe the loop as self-perpetuating.

So a scalp can feel tight and flake in a Swedish February while the roots look oily by day two. The two observations are not in conflict: the flaking scalp is asking for its barrier and its yeast to be looked after, not for its oil to be stripped. The same lipid barrier is described for the face in ceramides and the skin barrier.

What is dandruff, and is it the same thing as seborrhoeic dermatitis?

Dandruff is the mildest end of seborrhoeic dermatitis rather than a separate condition. The two sit on one spectrum, which is why the same treatments work across it.

StatPearls describes dandruff explicitly as the mildest form of seborrhoeic dermatitis and as its non-inflammatory variant. The prevalence figures follow the same logic. A 2025 review in the Journal of Cutaneous Medicine and Surgery puts dandruff at 17 to 50 per cent of adults and seborrhoeic dermatitis at 1 to 14.3 per cent, while the Biomedicines review gives a pooled global figure of 4.38 per cent. Roughly one person in two flakes. Roughly one in twenty has the inflammatory version.

The mechanism is a three-way interaction, and only one of the three is a microbe. Malassezia yeasts, chiefly M. restricta and M. globosa, live on almost every adult scalp. Whole-genome analysis published in the Journal of Investigative Dermatology Symposium Proceedings found that M. globosa lacks a fatty acid synthase and carries 13 secreted lipases, so it cannot build its own fatty acids and must take them from host sebum. Splitting sebum triglycerides releases free fatty acids, among them oleic acid, which the Biomedicines review describes as penetrating the stratum corneum, promoting inflammation and inducing desquamation.

The third factor is your own skin. StatPearls states that neither the level of sebum produced nor the amount of yeast appears to be a significant factor in who develops the condition. Almost everyone carries the yeast. Not everyone reacts to it, and that susceptibility is something research has not yet learned to measure.

What we do know is what works. Treatment is topical and reasonably well studied. A Cochrane review of 51 trials and 9,052 participants found ketoconazole gave a 31 per cent lower risk of failed clearance against placebo at four weeks, on low-quality evidence, and ciclopirox a risk ratio of 0.79 on moderate-quality evidence. Both are sold without prescription in Sweden.

What does itching, or a scalp that hurts to touch, mean?

It means something is irritating or sensitising the skin, and it is common enough to have its own literature.

A 2023 review in Skin Appendage Disorders puts sensitive scalp at 30 to 50 per cent of the general population, more often in women. Trichodynia, meaning actual pain in the scalp or in the hair itself, is reported by 17 to 35.7 per cent of people who are losing hair, again mostly women.

The proposed mechanisms are nerve hyperreactivity through TRPV1 channels, local immune activation, and the same barrier dysfunction described above with raised pH and increased water loss. The same review also lists what a doctor considers first: seborrhoeic dermatitis, psoriasis, atopic dermatitis, contact eczema, postherpetic neuralgia. Each of those has its own treatment, so a persistent itch is a question with an answer.

1177 gives the practical version. Contact a health centre if seborrhoeic eczema is causing you significant trouble, and contact one as well if hair is coming out alongside itching or redness at the root, or if it has not regrown within six months. Persistent scaling, persistent itch, pain, or loss in defined patches is a question for a doctor rather than for a shampoo or a supplement.

Does scalp massage do anything?

Possibly a little. The two studies that exist are small.

The first, published in Eplasty in 2016, followed nine healthy Japanese men aged 25 to 46 who used a scalp massage device for four minutes a day for 24 weeks, with the untreated side of their own scalp as the comparison. Hair thickness went from 0.085 mm to 0.092 mm. Hair count on the massaged side fell at 12 weeks before recovering, which the authors attribute to temporary telogen shedding.

The second is a survey. English and Barazesh contacted 1,899 people who had accessed online scalp massage instructions; 340 completed the questionnaire and 327 attempted the protocol, which was twenty minutes twice a day. Of those, 68.9 per cent reported that shedding had stabilised or that hair had regrown. The authors themselves list the limitations: no control group, self-reported outcomes, choice-supportive bias, recall bias for both adherence and results.

Nine men with a device, and a self-selected survey with nothing to compare against: that is what we do not yet know. What we do know is that massage is pleasant, costs nothing and is very unlikely to do harm. Enjoy it for what it is, and look to the follicle's supply for the rest.

What does the follicle need from the inside?

An unusual amount of energy, a steady supply of building material, and a few nutrients with authorised claims about hair. This is the level a food supplement works at, and where our selection begins.

A growing follicle sustains one of the highest rates of cell division seen in any mammalian tissue, according to a 2021 paper in Scientific Reports, and meets that demand largely through aerobic glycolysis, converting about 90 per cent of its glucose to lactate even when oxygen is available. The same group showed that human scalp follicles run an internal Cori cycle, recycling their own lactate back into glycogen rather than exporting it.

A tissue this costly is a tissue the body can afford to pause, because hair carries no survival function. Under illness, energy restriction or sustained physiological stress, hair is among the first things deprioritised. The reverse also holds: a steadily supplied follicle has what it needs to keep doing its expensive work.

On the nutrient side, the permitted claims list under Regulation (EU) 432/2012 authorises three wordings about hair: biotin contributes to the maintenance of normal hair, zinc contributes to the maintenance of normal hair, and selenium contributes to the maintenance of normal hair. Vitamin B6 contributes to normal protein metabolism and to the regulation of hormonal activity.

Within that frame we selected Hair Beautification. The core is Keranat®, a millet seed extract made by Robertet in Grasse, a specialist manufacturer of botanical extracts with a human study on its own material. In a study on Keranat, randomised, double-blind and placebo-controlled, women took 300 mg a day for twelve weeks. Keranat was studied at 300 mg per day. Hair Beautification contains 300 mg per daily dose. For us, the ingredient cannot be separated from its source, manufacturer and studied dose. What the study measured is set out in our article on Keranat and the millet study, and why we work with named raw materials from specialist manufacturers in branded ingredients.

Around it sit three nutrients at a nutritional level. Biotin at 50 µg, because biotin contributes to the maintenance of normal hair and normal skin. A 2017 review in Skin Appendage Disorders found 18 reported cases of biotin improving hair or nails, all in patients with an underlying condition, which tells you that biotin does its job as a daily supply rather than as a high-dose intervention. A 2019 review in Dermatology and Therapy read the literature the same way and noted that high doses can interfere with laboratory tests, one more reason to keep biotin at a nutritional level. We have written more about biotin and what it does separately.

Zinc at 10 mg, as zinc citrate, because zinc contributes to the maintenance of normal hair, normal skin and normal nails and to the normal function of the immune system. Vitamin B6 at 1.4 mg, because the follicle's building material is protein and vitamin B6 contributes to normal protein metabolism. All three sit at levels in line with the Nordic Nutrition Recommendations 2023. Four ingredients, each with a reason to be there: the follicle needs a supply, not a pharmacy. Twelve weeks in the Keranat study also means twelve weeks of a daily habit, which is why the jar is designed to stand out on a shelf and become part of the routine.

Why does hair fall out two to three months after the event that caused it?

Because the follicle does not release the hair when it stops growing it. It releases it at the end of a resting phase that lasts roughly four months.

In a healthy scalp about 85 per cent of follicles are in anagen, the growth phase, and 15 per cent in telogen, the resting phase. A follicle grows hair for close to four years, then rests for about four months before letting go. The phases, and what normal shedding looks like, are covered in how hair grows.

Telogen effluvium is what happens when a trigger pushes an abnormal share of follicles into telogen at the same time. StatPearls describes a causative event approximately three months before the shedding starts, with a range of one to six months, and notes that under significant stress up to 70 per cent of anagen hairs can precipitate into telogen. The listed triggers are recognisable: febrile illness, severe infection, major surgery, childbirth, hypothyroidism, crash dieting, low protein intake, iron deficiency.

The delay is why the cause gets missed. By the time the shedding is obvious in the shower drain, the influenza, the operation or the diet is months in the past and no longer feels connected to anything. The reassuring part sits in the same mechanism: once the trigger is behind you, the paused follicles go back to work, and this form of shedding reverses on its own.

For women this overlaps with a second, slower pattern. 1177 notes that people normally shed between 50 and 150 hairs a day, and that hereditary hair loss in women most often appears around menopause, thinning gradually until the scalp starts to show through. Those are two different processes on two different timescales. We have written about the biology of menopause elsewhere.

What is worth doing for your scalp and your hair?

Four things, and they work on different levels.

Wash often enough that sebum and its breakdown products are not sitting on the skin for days at a time. Frequency is individual, and no trial can tell you your number.

If you flake, an antifungal shampoo containing ketoconazole or ciclopirox is the intervention with evidence behind it, and it is sold without prescription in Sweden. Use it on the schedule on the box rather than occasionally.

If scaling, itch or soreness persists, if hair comes out in defined patches, or if shedding continues past six months, book an appointment. That is a dermatological question with dermatological answers.

Eat enough, and feed the follicle from within. This sounds trivial and is not. Energy restriction, low protein intake and iron deficiency all appear on the trigger list for telogen effluvium, and all three are common in the group that worries most about thinning hair. Iron is a question for a blood test, and the nutrients Swedish intakes most often run low in are covered in what Riksmaten shows.

The scalp is cared for from the outside. The follicle is supplied from within, and that is where Hair Beautification, hair vitamins with millet extract belongs: Keranat® at 300 mg, the dose in its placebo-controlled study, with biotin, vitamin B6 and zinc at levels in line with the Nordic Nutrition Recommendations 2023. Biotin and zinc contribute to the maintenance of normal hair. We have done the selection so that you do not have to. More on how the hair system fits together sits on our hair page.

Further reading

Frequently asked questions

Why does my scalp itch?
Itch means something is irritating or sensitising the skin. Sensitive scalp is reported in 30 to 50 per cent of the general population, more often in women. If the itch persists, a doctor will first consider seborrhoeic dermatitis, psoriasis, atopic dermatitis and contact eczema, each of which has its own treatment.

Is dandruff the same thing as seborrhoeic dermatitis?
They sit on one spectrum. Dandruff is described as the mildest, non-inflammatory form of seborrhoeic dermatitis, which is why the same treatments work across the range. Roughly one adult in two flakes, while 1 to 14.3 per cent have the inflammatory version.

What helps against dandruff?
An antifungal shampoo containing ketoconazole or ciclopirox is the intervention with evidence behind it, and both are sold without prescription in Sweden. A Cochrane review of 51 trials and 9052 participants found a 31 per cent lower risk of failed clearance with ketoconazole against placebo at four weeks. Use it on the schedule on the box rather than occasionally.

Can a supplement help a dry or flaking scalp?
A flaking scalp is a barrier and yeast question, and it is looked after from the outside, with a shampoo that has trial data behind it. A food supplement works on a different level: the follicle's supply from within. Hair Beautification is built for that level, with Keranat at its studied dose and with biotin and zinc, which contribute to the maintenance of normal hair.

Does scalp massage work?
The evidence is two small studies: nine Japanese men using a massage device for 24 weeks, and an uncontrolled survey of 327 people. That is too little to call massage a treatment. It is pleasant, costs nothing and is very unlikely to do harm.

Why does hair fall out months after I was ill?
The follicle does not release the hair when it stops growing it. It releases it at the end of a resting phase lasting roughly four months. Telogen effluvium is therefore described with a causative event approximately three months before the shedding starts. Once the trigger is behind you, the follicles go back to work, and this form of shedding reverses on its own.

Sources