FIG. 01 · THE FOUR CONTRIBUTORS

01. Hormonal

The endocrine system shapes follicle behaviour over time. Androgens, particularly dihydrotestosterone (DHT), are the most extensively studied hormonal influence on the hair growth cycle, and follicle sensitivity to them varies by genetics, age, and life stage.

The published nutritional literature has investigated several botanicals in the context of androgen-related hair concerns. HR01.1 includes two of these.

02. Oxidative

Hair follicles are metabolically active and produce reactive oxygen species as a by-product of normal cellular function. Cellular antioxidant defences counter this, and their efficiency depends on nutritional status.

The published research has investigated antioxidant compounds, particularly members of the vitamin E family and trace minerals with antioxidant cofactor function in this context.

03. Structural

Hair fibre is composed primarily of keratin, a sulphur-rich fibrous protein assembled from specific amino acids. The synthesis of keratin requires both the amino acid building blocks and mineral cofactors involved in disulphide bond formation.

This is the contributor with the clearest authorised regulatory framework: zinc and selenium both have GB-authorised health claims for the maintenance of normal hair.

04. Stress-related

Physiological and psychological stress alter the hair growth cycle. Cortisol patterns, sleep quality, and overall physiological load influence the proportion of follicles in active growth (anagen) versus shedding (telogen) phase.

The published research has investigated nutritional support for stress-response systems, including adaptogenic botanicals long used in traditional medicine and now examined in modern clinical trials.

FIG. 02 · DOSE RATIONALE SUMMARY

* Standard standalone supplement range for L-Cystine; safe upper intake assessment 750 mg/day for adults (VKM 2016).
† HR01.1 dose is below the standalone trial range. See per-active rationale for the formulation prioritisation.

Pumpkin Seed Oil — 400 mg

Cold-pressed oil from Cucurbita pepo seeds, naturally rich in phytosterols (including delta-7 phytosterols), unsaturated fatty acids, and tocopherols.

The 400 mg daily dose reflects the protocol used in Cho et al. (2014), a 24-week randomised, double-blind, placebo-controlled trial published in Evidence-Based Complementary and Alternative Medicine. The trial investigated cold-pressed pumpkin seed oil at 400 mg daily in 76 men with mild-to-moderate androgenetic alopecia.

Saw Palmetto Extract — 320 mg

Lipophilic fruit extract from Serenoa repens, naturally containing fatty acids, phytosterols, and small concentrations of polyphenolic compounds. The fatty acid fraction is the most studied compositional feature.

The 320 mg daily dose sits at the upper end of the dose range investigated in published trials of saw palmetto in androgen-related contexts. Evron et al. (2020), a systematic review published in Skin Appendage Disorders, identified an investigated dose range of 100–320 mg across the published literature on oral and topical saw palmetto supplements in alopecia.

Tocotrienol Complex — 100 mg

A mixed-isoform extract of tocotrienols, the less-common members of the vitamin E family, distinct from the alpha-tocopherol found in most vitamin E supplements. Sourced from palm fruit.

The 100 mg daily dose reflects the protocol used in Beoy et al. (2010), an 8-month trial published in Tropical Life Sciences Research. The trial investigated mixed tocotrienol supplementation at 100 mg daily in 38 adult volunteers with hair loss.

L-Cystine — 450 mg

A sulphur-bearing amino acid composed of two cysteine residues linked by a disulphide bond. L-Cystine is one of the principal amino acids in keratin (which contains approximately 16% L-cystine by composition) and is structurally significant in hair fibre formation.

The 450 mg daily dose sits within the standard standalone supplemental range for L-Cystine (typically 250–500 mg per capsule across European nutritional supplements) and well within the upper safe intake assessment of 750 mg/day for adults established by the Norwegian Scientific Committee for Food Safety. This is meaningfully higher than the L-Cystine content investigated in published multi-ingredient hair supplement trials, including Lengg et al. (2007), where L-Cystine was one component within a B-vitamin and medicinal yeast complex at lower per-dose levels.

L-Lysine — 450 mg

An essential amino acid (one the human body cannot synthesise from other compounds) involved in collagen synthesis and iron absorption. While L-Lysine is not itself a primary structural component of hair, dietary lysine status interacts with iron metabolism, which is required for hair follicle cycling.

The role of L-Lysine in hair-related nutrition has been reviewed in Almohanna et al. (2019) in Dermatology and Therapy and Guo and Katta (2017) in Dermatology Practical & Conceptual. Published clinical investigations of L-Lysine specifically for hair have used 1,000–1,500 mg daily, paired with iron supplementation in women with chronic telogen effluvium and low ferritin status.

The 450 mg daily dose in HR01.1 is below those trial levels. This is a deliberate formulation decision. A four-capsule daily dose carries a finite mass of actives; we have prioritised that capsule load toward the actives with the most direct evidence in hair-specific clinical research — Pumpkin Seed Oil, Saw Palmetto, Tocotrienol, Ashwagandha, and the regulated minerals — and dosed those at the levels investigated in the literature. L-Lysine is included to support the formulation's amino acid profile alongside L-Cystine, not as a standalone replacement for the iron-paired protocols described in the literature. Customers with diagnosed iron-related telogen effluvium should consult a healthcare professional, who can advise on iron supplementation and L-Lysine dosing appropriate to their ferritin status.

MSM — 500 mg

Methylsulfonylmethane, an organic sulphur compound. MSM functions as a bioavailable sulphur donor, and sulphur is required for keratin synthesis (the disulphide bonds that give hair its structural integrity are sulphur-based).

Published clinical research on MSM specifically for hair has typically investigated doses of 1,000–3,000 mg daily as a standalone intervention. The 500 mg daily dose in HR01.1 is below those levels, by deliberate formulation decision. Capsule load is finite; sulphur is already supplied through L-Cystine, which sits at meaningful nutritional levels in the formulation. MSM at 500 mg is included as a complementary sulphur source rather than as a primary intervention, with the priority of the protocol allocated to actives with stronger and more direct hair-specific clinical evidence.

Ashwagandha Extract — 300 mg

Root extract of Withania somnifera, traditionally used in Ayurvedic practice and now widely studied in modern nutritional research. Contains naturally occurring withanolides as the characterising compounds.

The 300 mg daily dose sits at the lower end of doses investigated in clinical research on standardised ashwagandha root extract. Chandrasekhar et al. (2012), a 60-day randomised, double-blind, placebo-controlled trial published in the Indian Journal of Psychological Medicine, investigated 300 mg of high-concentration full-spectrum ashwagandha root extract twice daily in 64 adults under stress. We have selected the once-daily 300 mg dose to deliver ashwagandha at the lower end of the investigated range. Note: ashwagandha is currently under active review by the UK Food Standards Agency Committee on Toxicity. We monitor this review closely and will reformulate if regulatory guidance changes.

Vitamin D3 — 50 µg (1,000% NRV)

Cholecalciferol, the form of vitamin D synthesised by the human skin in response to UVB exposure. The active form involved in cellular signalling. Sourced from lichen (vegan-suitable).

The 50 µg (2,000 IU) daily dose reflects the upper end of doses investigated in the published research on vitamin D status, balanced against UK Tolerable Upper Intake Level guidance (100 µg/day from all sources). This dose is appropriate for individuals not taking other vitamin D supplements; cumulative intake guidance applies.

Zinc — 15 mg (150% NRV)

Provided as zinc citrate, a chelated form selected for bioavailability. Zinc is required as a cofactor for over 300 enzymatic processes, including those involved in keratin synthesis. Zinc is the subject of an authorised GB health claim for the maintenance of normal hair, skin, and nails.

The 15 mg daily dose is supplied at 150% of the Nutrient Reference Value, well within the UK Tolerable Upper Intake Level of 25 mg/day. This dose is appropriate for individuals not taking other zinc supplements; cumulative intake guidance applies.

Selenium — 55 µg (100% NRV)

Provided as selenomethionine, the form found in dietary protein sources. Selenium is required as a cofactor for selenoenzymes including glutathione peroxidase, which contributes to cellular antioxidant defences. Selenium is the subject of an authorised GB health claim for the maintenance of normal hair and nails.

The 55 µg daily dose is supplied at 100% of the Nutrient Reference Value, well within the UK Tolerable Upper Intake Level of 300 µg/day.