Last update: March 2026 — Written by the ORVOVA team, proofread by our dermocosmetics advisor.
The food supplement section of your pharmacy is a minefield.Dozens of boxes, all promising: “stronger hair”, “proven anti-hair loss”, “viscous regrowth”.Prices range from 8 to 60 euros.And the seller is as lost as you.
The reality: some supplements have solid clinical data.Others are pure marketing with no scientific basis.And the majority are in a gray area where the formula is correct but the dosage is insufficient, or the right ingredient is there but in a form that your body does not assimilate.
This article dissects the active ingredients one by one, with the effective doses, the forms to favor and those that you can save.
How do hair supplements work
Before talking about ingredients, we must understand a fundamental principle: hair is a non-essential tissue.
Your body has priorities.The heart, the brain, the liver, the muscles — all receive their nutrients first.Hair and nails come last in the metabolic queue.Which means that even a slight deficiency, well before causing classic clinical symptoms, can already manifest itself in hair loss or slowdown in growth.
This is the basic principle of hair supplements: filling in subclinical deficiencies which starve the hair follicle.Not magically stimulate growth — just give the hair what it needs to grow normally.
What the hair follicle consumes
The follicle is one of the most metabolically active tissues in the body.A hair grows approximately 1 cm per month, which requires intense cell division in the follicular matrix.This activity requires:
- Iron — for the transport of oxygen to the dermal papilla
- Zinc — for protein synthesis (hair is made of keratin, a protein)
- Biotin — coenzyme involved in the synthesis of keratin
- Sulphurous amino acids — the building blocks of keratin (methionine, cysteine)
- Vitamin D — regulator of the follicular cycle
- Essential fatty acids — for the cell membrane of the follicle
[Image: The hair cycle and essential nutrients at each growth phase]
Assets that have solid evidence
Iron: number one in hair deficiencies
It is the deficiency most frequently associated with hair loss, particularly in women.Several studies show that ferritin (the body's iron stock) is significantly lower in women suffering from telogen effluvium than in controls.
The optimal threshold for hair is higher than the classic clinical threshold.Most laboratories consider a "normal" ferritin from 12-15 ng/mL.But trichologists recommend a minimum of 40 ng/mL, ideally 70 ng/mL, for optimal hair growth.
Preferred form: iron bisglycinate (better absorption, fewer gastrointestinal effects) or liposomal iron.Avoid ferrous sulfate which constipates and irritates the stomach.
Effective dose: 14 to 28 mg of elemental iron per day if documented deficiency.Never supplement with iron without prior blood testing — excess iron is toxic (hemochromatosis).
Zinc: essential but double-edged
Zinc is involved in cell division, protein synthesis and immune function — three pillars of hair health.Zinc deficiency causes well-documented hair loss, but also brittle nails and slowed healing.
The trap: an excess of zinc depletes copper, which causes... hair loss.Zinc supplementation is a delicate balance.
Preferred form: zinc bisglycinate or zinc picolinate (higher bioavailability than zinc oxide found in inexpensive formulas).
Effective dose: 15 to 30 mg per day, maximum.Beyond that, also supplement with copper (1-2 mg) to avoid depletion.
Vitamin D: the little-known regulator of the hair cycle
Research over the last ten years has revealed the central role of vitamin D in the follicular cycle.VDR (Vitamin D Receptor) receptors are present on the cells of the dermal papilla and participate in the initiation of the anagen phase (growth).
In France, 80% of the population is deficient in vitamin D between October and April.This is probably one of the factors in the seasonal fall.
Preferred form: vitamin D3 (cholecalciferol), not D2.In oil format for better absorption (fat-soluble vitamin).
Effective dose: 1000 to 4000 IU per day depending on your blood level.Objective: 40-60 ng/mL (blood 25-OH-D3 dosage).
[Image: Comparative bioavailability of different forms of iron, zinc and vitamins]
Popular but overpriced assets
Biotin: the most lucrative myth
Biotin (vitamin B7/B8) is the star ingredient in almost all hair supplements.It is also the one with the weakest evidence of effectiveness in non-deficient people.
The problem: biotin deficiency is extremely rare in the general population.Biotin is produced by intestinal bacteria, present in many foods (eggs, liver, nuts) and daily requirements are low (30 mcg).
Supplements often dose at 5,000-10,000 mcg, or 150 to 300 times the recommended intake.At these doses, biotin showed no additional hair benefit in people with normal status.It can even falsify the results of certain blood tests (thyroid, cardiac troponin) — an underestimated risk.
When it really works: in the rare people with a real deficiency (treatment with antiepileptics, excessive consumption of raw egg whites, certain genetic diseases).For others, it's a placebo at 30 euros per month.
Beer's yeast: nice but limited
Beer's yeast (Saccharomyces cerevisiae) provides group B vitamins, amino acids and minerals.It's an honest "general" supplement, but not specialized for hair.Its nutritional profile is interesting for vegetarians (rich in B12), but the doses of zinc and iron are too low to correct a hair deficiency.
Spirulina: good for health, modest for hair
Spirulina is a superfood rich in protein, iron and antioxidants.But the iron in spirulina (non-heme iron) has poor bioavailability, and the quantities of zinc and biotin are insufficient for a specific hair impact.It is a good general supplement, not a targeted treatment.
Emerging assets: promising but awaiting proof
Vitamin E (tocotrienols)
A 2010 study (Beoy et al.) showed that tocotrienols (a specific form of vitamin E) increased the number of hairs by 34% in subjects supplemented for 8 months.Small study (38 participants), but encouraging results.Tocotrienols are present in palm oil, brown rice and barley.
Ashwagandha (Withania somnifera)
This Ayurvedic adaptogen reduces cortisol (stress hormone) by 30% on average in clinical studies.Chronically elevated cortisol prolongs the catagen phase and flushes follicles with telogen — this is the mechanism of stress loss.Ashwagandha does not act directly on the follicle, but on the stress that attacks it.Indirect, but logical approach.
MSM (methylsulfonylmethane)
MSM is an organic sulfur donor.Sulfur is a structural component of keratin (disulfide bonds).Some low-quality studies suggest a benefit on hair growth and thickness, but the data are too limited to conclude.
[Image: Comparison table — complement, effective dose, level of evidence, average price]
The combined approach: interior + exterior
The supplements work from the inside.But the hair follicle is also accessible from the outside, via the scalp.The most comprehensive strategy combines both approaches.
Why the topical approach complements supplements
A supplement takes 3 to 6 months to show a visible effect — time for nutrients to reach the follicle via the bloodstream and a new hair cycle to begin.A topical treatment acts directly on the scalp, with a potentially shorter onset of action.
Certain active ingredients are even more effective when applied locally than when ingested.This is the case of rosemary (a study by Panahi et al. 2015 showed effectiveness comparable to Minoxidil 2% in topical application), Redensyl (patented active ingredient targeting follicular stem cells) and Aminexil (anti-perifollicular fibrosis).
Interior/exterior synergy
Concretely, the most pragmatic combination looks like this:
- Interior: a supplement containing iron (if documented deficiency), zinc 15 mg, vitamin D3 2000 IU
- Exterior: a hair serum concentrated in valid active ingredients, applied directly to the scalp
The ORVOVA Roll-On Hair Regrowth Serum combines 3% rosemary, 2% Redensyl, 2% Aminexil and 2% Anagain in topical roll-on application — four active ingredients that target complementary mechanisms of hair loss.The roll-on applicator massages the scalp during application, stimulating local microcirculation.
This dual approach (target supplements + topical serum) is the one recommended by most trichologists to maximize the chances of results.
How to choose a hair supplement: the checklist
Objective criteria
- The actual dosage of active ingredients — not the quantity of extract, but the quantity of active molecule.A supplement that says “500 mg of zinc extract” says nothing;“15 mg of elemental zinc (bisglycinate)” says it all.
- The form of the active ingredients — bisglycinate >picolinate >citrate >oxide for minerals.Methylfolate >folic acid for B9.Methylcobalamin >cyanocobalamin for B12.
- Formula transparency — avoid “proprietary blends” that mask individual dosages.
- Certifications — NF, GMP/BPF, controlled by a third-party laboratory.
- The absence of “sprinkling” — a good supplement contains 4-6 active ingredients at an effective dose.A bad one contains 20 in a homeopathic dose.
Warning signals
- Promises results in “2 weeks” (the hair cycle lasts 3-6 months minimum)
- Before/after too spectacular (often done in different lighting conditions)
- Absence of precise dosages on the label
- Mega-doses of biotin (5000+ mcg) as main selling point
- Prices above 40 euros/month without justification by the quality of the ingredients
The essential blood test before any supplement
This is the most important point of this article: never supplement blindly.A basic capillary blood test costs between 30 and 80 euros (partially reimbursed) and saves you from wasting months and hundreds of euros on unnecessary supplements.
The minimum balance sheet
- Ferritin (objective > 40 ng/mL, ideal 70)
- 25-OH-Vitamin D (target 40-60 ng/mL)
- TSH + free T4 (thyroid, common cause of falls)
- Serum zinc (goal > 80 mcg/dL)
- NFS (anemia, inflammation)
The extended balance sheet (if significant or persistent fall)
- Hormones: estradiol, free testosterone, DHEA-S, progesterone
- Salivary cortisol (chronic stress)
- Fasting insulin (insulin resistance, linked to androgenic alopecia)
- CRP (systemic inflammation)
[Image: Annotated hair blood test — normal values vs optimal values for hair]
The verdict: pragmatism rather than marketing
Hair supplements are neither miracles nor scams.They are tools — effective when they target a real deficiency, useless when they sprinkle trendy ingredients on already solid nutritional ground.
The pragmatic strategy:
- Have a blood test
- Correct documented deficiencies with bioavailable forms at effective doses
- Complete with a targeted topical treatment to act directly on the follicle
- Give yourself 4 to 6 months of regular monitoring before judging the results
And save the money from overdosed biotin — it will be better invested elsewhere.
Frequently asked questions
How long do you need to take a hair supplement to see results?
Minimum 3 months, ideally 6 months.The complete hair cycle lasts 2 to 7 years, and a hair that enters the growth phase today will only be visible after several weeks.Most clinical studies evaluate results at 6 months.The first signs (reduction in shedding, appearance of down) generally appear between 8 and 12 weeks.
Can you take several hair supplements at the same time?
This is rarely necessary and potentially risky.Accumulating two “hair” supplements often creates overdoses of biotin and zinc, and imbalances between minerals.Better to choose a complete supplement or specifically supplement deficiencies identified by blood test.
Is biotin really useless?
Not useless — useless in non-deficient people, which represents the vast majority of the population.If your assessment shows a biotin deficiency (rare), supplementation is effective.Otherwise, mega-doses provide no additional benefit.Biotin in a dose that far exceeds your needs does not "boost" keratin production — your body simply excretes the excess in the urine.
Can food supplements replace topical treatment?
No, they act on different mechanisms.Supplements correct nutritional deficiencies that limit growth.Topical treatments act directly on the follicle by stimulating stem cells, inhibiting perifollicular fibrosis or blocking DHT locally.The ideal is to combine the two to maximize results.
Do hair supplements also make body hair grow?
No.Unlike oral Minoxidil (which is a medication, not a supplement), hair supplements do not modify body hair.They provide nutrients that the body uses for all of its functions — hair benefits, but not in a selectively hypertrichous way.
I am vegetarian/vegan: which supplements should I favor?
The most common deficiencies among vegans are iron (heme form absent), zinc (bioavailability reduced by phytates in cereals), vitamin B12 (absent in plants) and vitamin D (essentially animal food sources).Favor iron bisglycinate (vegetable and well absorbed), zinc picolinate, B12 methylcobalamin and D3 from lichen (the only source of plant D3).A blood test is even more important for vegans.
