Hair loss: understanding before treating.

6 min. read

10/07/2026

CELLULAR BEAUTY · JOURNAL

Hair Loss:
Understanding Before Treating.

Losing one's hair is often seen as an inevitability. This is rarely the case. In the vast majority of situations, hair loss has an identifiable cause—and a cause that can be treated.

— THE HAIR CYCLE

What few people know:
each hair has its own clock

A hair does not grow indefinitely. It goes through a life cycle in three distinct phases, controlled by precise hormonal, nutritional, and cellular signals. Understanding this cycle means understanding the origin of hair loss—and why some treatments require several months before showing results.

The anagen phase is the active growth phase: the hair follicle produces the hair fiber at a rate of approximately 1 cm per month. It lasts from 2 to 7 years depending on genetics and nutritional status. At any given time, it concerns 85% of our hair. This is the phase we seek to prolong and strengthen.

The catagen phase is a short transition phase (2 to 3 weeks) during which the follicle retracts and ceases production. It concerns about 1 to 2% of hair at any given time.

The telogen phase is the resting phase: the follicle is inactive for 3 to 4 months, then the hair naturally falls out to make way for a new anagen cycle. Normally, it concerns 13 to 15% of hair. Losing 50 to 100 hairs per day is therefore perfectly physiological—it is the normal consequence of this rotation.

Pathological hair loss occurs when too many follicles simultaneously switch to the telogen phase, or when the anagen phase gradually shortens. In both cases, the cause is almost always identifiable.

Fig. 1 — The hair cycle and main disruption factors

SCIENTIFIC REFERENCE

Serum ferritin and hair loss in women: a controlled study

Rushton D.H.

Clinical and Experimental Dermatology · 2002 · Vol. 27(5) · pp. 396–404

Access publication → https://doi.org/10.1046/j.1365-2230.2002.01076.x

This landmark clinical study established a direct link between serum ferritin levels and hair loss in women. Results show that a ferritin level below 40 µg/L—although considered "within normal limits" by some laboratories—is sufficient to significantly weaken the hair follicle and reduce the duration of the anagen phase. Iron deficiency is now recognized as the primary cause of hair loss in women of childbearing age.

"Hair loss is almost never an inevitability. It is most often a signal—nutritional, hormonal, or emotional—that the body sends."

— THE REAL CAUSES

Five mechanisms that trigger
abnormal hair loss

The vast majority of hair loss is referred to as reactive or diffuse—meaning it has an identifiable cause and is potentially reversible once that cause is treated. Here are the five most common mechanisms:

THE MOST COMMON CAUSES OF HAIR LOSS

Telogen effluvium	The most common cause of massive hair loss. A triggering event (intense stress, fever, childbirth, surgery, severe dieting, discontinuing contraceptives) precipitates up to 30% of hairs into the telogen phase simultaneously. Hair loss occurs 2 to 3 months later—a delay that often makes the connection difficult to establish. Effluvium is reversible once the cause is treated.
Iron deficiency (low ferritin)	Ferritin is the iron storage marker. Below 40 µg/L, the hair follicle is weakened even if hemoglobin is normal. Iron deficiency affects between 30 and 50% of women of childbearing age and should always be investigated in cases of hair loss. Heavy periods and repeated pregnancies are the primary causes of depletion.
Nutritional deficiencies	Keratin, which makes up 90% of the hair fiber, requires sulfur amino acids (cysteine, methionine), zinc, selenium, B vitamins (biotin, B12, B9), and silicon to be synthesized correctly. Any deficiency in these cofactors slows down keratinization, weakens the hair, and shortens the anagen phase. Restrictive diets and digestive disorders are often implicated.
Hormonal imbalances	Dihydrotestosterone (DHT) is responsible for androgenetic alopecia by progressively miniaturizing follicles. But other hormones play a role: drops in estrogen (menopause, postpartum, stopping the pill), hypothyroidism, polycystic ovary syndrome (PCOS), and chronic stress via cortisol all disrupt the hair cycle.
Follicular oxidative stress	Free radicals accumulate in the scalp with age, pollution, and an oxidizing lifestyle. They damage follicular matrix cells, shorten the anagen phase, and accelerate fiber miniaturization. This is the main mechanism of premature hair aging. Antioxidants—vitamin E, selenium, glutathione—are key protective agents.

50-100

HAIR LOST/DAY = STRICTLY NORMAL

2-3 months

DELAY BETWEEN SHOCK AND VISIBLE HAIR LOSS

40 µg/L

CRITICAL FERRITIN THRESHOLD FOR THE FOLLICLE

90 %

OF THE HAIR FIBER IS MADE OF KERATIN

— KEY HAIR NUTRIENTS

What the hair follicle
needs to function

The hair follicle is one of the body's fastest-renewing cell structures. It consumes a considerable amount of energy and nutrients to maintain its anagen phase. In case of restriction — whether dietary, digestive, or related to a targeted deficiency — the follicle is one of the first organs sacrificed by the body in favor of vital functions.

ESSENTIAL NUTRIENTS FOR HAIR HEALTH

Hydrolyzed Keratin (Cynatine® HNS)	Keratin is the structural protein of hair. The intake of bioavailable hydrolyzed keratin directly provides the building blocks of the hair fiber. Cynatine® HNS is a patented keratin whose specific hydrolysis ensures optimal absorption and integration into the hair structure.
L-cysteine and L-methionine	These two sulfur-containing amino acids are direct precursors of keratin. Cysteine forms the disulfide bonds that give hair its strength and elasticity. Methionine is essential for cellular protein synthesis and methylation (epigenetic regulation of the hair cycle).
Zinc	Zinc is a cofactor for over 200 enzymes involved in cell division, protein synthesis, and keratinization. A zinc deficiency leads to rapid hair weakening, diffuse hair loss, and altered pigmentation. It is often deficient in people with restrictive diets or intestinal malabsorption.
Iron (ferritin)	Iron is essential for the proliferation of follicular matrix cells. A ferritin level below 40 µg/L reduces the duration of the anagen phase and weakens the hair fiber. Lactoferrin (Active+ Lactoferrin, No. 09) optimizes iron metabolism without risk of overload — particularly relevant for women with heavy periods.
Selenium and vitamin E	Powerful antioxidants, they protect follicular cells from oxidative stress and support glutathione peroxidase synthesis. Selenium also participates in thyroid regulation — and hypothyroidism is one of the most common endocrine causes of hair loss.
Silicon (bamboo extract)	Silicon is a structuring trace element of the extracellular matrix. It strengthens the mechanical resistance of the hair fiber, improves hair elasticity, and supports nail strength. Bamboo extract is the most concentrated natural source of bioavailable organic silicon.

“The hair follicle is a faithful indicator of overall nutritional status. What you see falling in the shower is often a reflection of what your body is no longer receiving.”

— BIOLOGYST FORMULATION

Hair Nail Regenesis:
an integrated approach to keratinization

HAIR NAIL REGENESIS (No. 05) was designed to act simultaneously on both dimensions of hair health: the supply of structural substrates (keratin, sulfur-containing amino acids, silicon) and the correction of enzymatic cofactors (zinc, selenium, iron, B vitamins) essential for their utilization by the follicle.

KEY ACTIVE INGREDIENTS OF HAIR NAIL REGENESIS · MECHANISMS OF ACTION

Cynatine® HNS · 500 mg	Patented keratin hydrolysate with high bioavailability. Directly supplies amino acids and peptides to the hair fiber. Clinical trials: reduced hair loss, improved tensile strength and hair shine in 90 days.
L-cysteine · 200 mg	Main sulfur amino acid in keratin. Forms disulfide bonds that give hair its cohesion and mechanical strength. Cofactor in glutathione synthesis — antioxidant protection of the follicle.
Bamboo extract · 150 mg (of which 112 mg silicon)	Concentrated source of bioavailable organic silicon. Strengthens the perifollicular extracellular matrix, improves fiber resistance and nail strength. Contributes to hair elasticity and volume.
L-methionine · 50 mg	Essential sulfur amino acid, cysteine precursor. Essential for protein synthesis and cellular methylation that regulates gene expression involved in the hair cycle.
Zinc 10 mg · Selenium 50 µg · Iron 7 mg	Fundamental mineral triad: zinc activates keratinization enzymes, selenium protects follicular cells and regulates the thyroid, iron supports cell proliferation of the matrix. Balanced combination to cover the three most frequent deficiencies involved in hair loss.
Vitamin B complex + A + E	Biotin (B7) is a cofactor for keratin synthesis. B12 and B9 support cell proliferation of the hair bulb. Vitamin A regulates keratinocyte differentiation. Vitamin E protects follicular cell membranes from oxidative stress.

Dosage and duration of treatment

3 capsules per day, preferably in the morning or spread throughout the day with meals. The treatment should last at least 2 to 3 months — an incompressible duration linked to the hair cycle: new hair in the anagen phase initiated by the treatment will only be visible after 6 to 12 weeks of growth. Patience is a component of the treatment.

Vegetable capsule. Contains vitamin A: not recommended for pregnant women. Can be combined with Lactoferrine Active+ for low ferritin or heavy periods to optimize iron metabolism.

— THE RECOMMENDED COMBINATION

When Hair Nail Regenesis
is not enough on its own

In certain situations — confirmed iron deficiency, postpartum effluvium, chronic stress — Hair Nail Regenesis benefits from being combined with other BIOLOGYST supplements to address underlying mechanisms:

COMPLEMENTARY COMBINATIONS ACCORDING TO PROFILE

Low ferritin (< 40 µg/L)	Combine with Lactoferrine Active+: lactoferrin regulates iron absorption and metabolism without risk of overload. It optimizes the bioavailability of dietary iron and complements the iron correction of Hair Nail Regenesis (which already provides 7 mg of iron, or 50% of the NRV).
Post-stress or postpartum effluvium	Combine with Magnesium Active+ and Serenity Flow to reduce chronic cortisol and support nervous system balance — a prerequisite for the resumption of a normal hair cycle. Untreated stress maintains effluvium even when deficiencies are corrected.
Hair loss related to excessive oxidative stress	Combine with Antioxidant Defense for follicular cell protection via quercetin, Setria® glutathione, and vitamin C. Particularly relevant for smoking, urban pollution, or intense physical activity.
Vitamin D deficiency (dosage < 30 ng/mL)	Combine with D3 Active+ (No. 11): vitamin D is a modulator of the hair cycle via its VDR receptors present in the follicles. Vitamin D deficiency is associated with increased hair loss and a reduction in the duration of the anagen phase.