Nourkrin hair growth, Viviscal and biotin:
what the evidence says about hair supplements and the myths

Do hair loss supplements work? The short evidence answer

Some hair supplements have small trials behind them, most have none, and none has been shown to replace medical treatment. A 2023 systematic review in JAMA Dermatology screened more than 6,000 citations and included 30 studies of supplements in people without a known deficiency; it found the strongest, though still limited, evidence for products including Viviscal and Nourkrin, with mild and rare side effects, and asked for larger randomised trials against active treatments.

That conclusion matters because hair loss is not one condition. Pattern hair loss is driven by inherited follicle sensitivity to DHT. Telogen effluvium is a shed triggered by illness, childbirth or a crash diet. Alopecia areata is autoimmune. Traction alopecia is mechanical. A capsule that helps one may do nothing for another, and buying one before the type is known is the commonest way months are lost.

In Singapore, health supplements do not need approval and are not evaluated by the Health Sciences Authority before sale; the dealer, from manufacturer to retailer, is responsible for safety and quality. A label that says "hair growth" has therefore not been checked by a regulator for that claim.

Nourkrin hair growth: what the trials show

Nourkrin is an oral supplement that its maker describes as proteoglycan replacement, based on marine-derived proteins with added vitamins and minerals. The published evidence is small. A 2006 randomised, double-blind, placebo-controlled trial of 55 people with hair loss of different causes reported a positive effect on objectively measured hair growth over its blinded phase, with no side effects reported, followed by an open-label extension.

Three points temper that result. The group was small and mixed, so it is not clear which type of hair loss responded. Most published work on Nourkrin comes from the same research group. And the 2023 systematic review that included it graded the field as a whole as needing larger trials with active comparators, meaning trials against a medicine that is already known to work.

What that means if you are considering Nourkrin

• Have the type of hair loss named first. Telogen effluvium often settles once the trigger has passed, which can make any supplement taken at the time look effective.
• Take standardised photographs before starting, so a later review compares like with like rather than relying on the mirror.
• Keep any medical therapy you have been prescribed. Nourkrin has not been tested as a replacement for it.
• Products made from marine sources are a question to raise if you have a fish or shellfish allergy.

“A supplement can top up what is missing. It cannot argue with DHT, and it should never be the reason a diagnosis is put off.”

Dr Sin YongOn supplements for hair loss

Viviscal hair supplement: the marine protein studies

Viviscal is an oral marine protein complex with vitamins and minerals, studied mainly in women with self-perceived thinning and in men with thinning hair. The trials are placebo-controlled but small, and they measure hair counts and thickness under study conditions rather than the changes people notice in daily life.

The 2023 systematic review placed Viviscal among the supplements with the higher-quality evidence of possible benefit, alongside Nourkrin, while noting that results should be read in the light of each study's design. That is a fair summary: some signal, not proof, and not evidence that it changes the course of pattern hair loss on its own.

Viviscal Pro and the retail version

Viviscal Pro is the name used for the version sold through clinics and pharmacies. Brand variants can differ in formulation, and a trial result applies only to the product that was tested, so the useful question for any variant is which formulation the published study used. The same applies to every supplement brand with more than one product on the shelf.

Whichever brand is chosen, the same rules apply as for Nourkrin: a named diagnosis first, baseline photographs, medical therapy kept in place, and a check for fish or shellfish allergy.

Vitamins for hair loss: when a deficiency matters

Vitamins and minerals matter for hair when a blood test shows a shortfall; topping up normal levels has not been shown to help. A 2019 review of vitamin A, the B vitamins, vitamins C, D and E, iron, selenium and zinc in non-scarring hair loss concluded that deficiency may be a modifiable risk factor, and that large placebo-controlled trials are still needed to show what supplementation adds.

The deficiencies that come up most often in a hair assessment are low iron stores (ferritin), which can be present without anaemia, low vitamin D and, less often, low zinc. Thyroid disorders are not a vitamin problem but produce the same diffuse thinning, which is why they are checked at the same time. The blood work guide for female hair loss explains which results matter and why no scalp camera can see them.

More is not better. Too much vitamin A or selenium can itself cause shedding, and supplements that combine several products can push intake higher than intended.

Biotin hair growth: who it helps

Biotin is the most heavily marketed hair vitamin and one of the least supported. A 2017 review found 18 reported cases of biotin helping hair or nails, and every one of them had an underlying cause such as biotin deficiency or a rare inherited condition; the authors found insufficient evidence for supplementation in healthy people. Real biotin deficiency is uncommon in people eating a normal diet.

High-dose biotin also distorts some laboratory tests, including certain thyroid tests, a problem the US Food and Drug Administration has warned about. Anyone taking it should say so before blood work, so that a result is not misread as a thyroid problem.

Castor oil for hair growth: what is known

There are no controlled trials showing that castor oil regrows hair on the human scalp. A 2026 narrative review of castor oil in dermatology found support for its use in improving hair lustre, described a proposed effect on pattern hair loss through inhibition of prostaglandin D2, a scalp signal linked to balding, and concluded that clinical trials are still needed to establish whether it works.

Castor oil is mostly ricinoleic acid, a thick, sticky oil. That makes it a reasonable conditioner for dry lengths, and it explains why hair can look fuller and shinier after an oil treatment. It does not change the follicle's response to DHT, which is what decides pattern hair loss.

Castor oil benefits for hair: conditioning, not regrowth

• It can make hair feel softer and look glossier, which is a cosmetic effect on the hair shaft.
• It has a rare but real risk: acute hair felting, where long hair mats into a hard mass that may need to be cut out. The same review lists it, along with contact dermatitis.
• It should not be used in place of treatment for a shed or a thinning pattern that is still progressing, because each year without treatment costs follicles.

The same reasoning applies to rosemary oil, onion juice and other kitchen remedies: a pleasant ritual is fine, provided it is not the whole plan.

Hair loss myths: MSG, caps and hair masks

Most food and lifestyle myths about hair loss confuse a cause of shedding with a cause of balding. Pattern hair loss is inherited and hormonal. What diet and stress can do is trigger telogen effluvium, a diffuse shed that starts two to three months after the trigger and usually settles once it passes.

MSG and hair loss

There is no good clinical evidence that monosodium glutamate (MSG) at ordinary dietary amounts causes hair loss. Diet does matter in a different way: crash dieting, very low protein intake and rapid weight loss are recognised triggers of telogen effluvium, and that is the dietary history a doctor asks about.

Caps, hats and helmets

Wearing a cap does not cause pattern hair loss. What can cause loss is repeated pulling on the same follicles: tight ponytails, braids, extensions and, occasionally, tight headwear pressed onto the same line every day. That is traction alopecia, and it is recognised by where the loss sits rather than by what someone wears. A clean, comfortable cap is not a risk.

Hair masks for hair loss

A hair mask conditions the hair shaft, which is dead keratin. It can reduce breakage, so fewer broken hairs collect in the shower, but it does not reach the follicle or change the hair cycle. Breakage and shedding look similar in the drain; a doctor separates them by looking at whether the shed hairs have a root bulb.

What to do instead: diagnosis, then treatment with evidence

The step that changes outcomes is naming the type of hair loss, because each type has a different treatment and a different timescale. At the clinic on Orchard Road, Dr Sin Yong examines the scalp himself with trichoscopy, stages pattern loss on the Norwood or Ludwig scale, and checks blood results such as ferritin, thyroid function and zinc where the history points to them.

• Pattern hair loss. Medical therapy is the foundation; the anti-hair-loss medications page sets out the stepwise protocol and its monitoring. Where follicles are miniaturised but alive, the hair regrowth treatment programme adds Regenera Activa micrografts and 1540 nm laser stimulation, sequenced by stage.
• Telogen effluvium. The trigger is found and the shed is explained; iron and thyroid are checked; most cases settle without a supplement.
• A measured deficiency. It is corrected, and rechecked, as part of the plan. Nutritional support can sit alongside medical therapy; it is not a stand-alone answer.
• Follicles that have gone. No supplement, oil or injection revives them, and a transplant assessment may be the honest next step.

The hair loss treatment options by diagnosis page shows how these layers fit together. If you are already taking a supplement, bring the packaging to the assessment, so the doses can be read and any overlap with prescribed treatment checked.