Hair Growth
Stimulated hair follicle activity and enhanced hair growth rate.
TL;DR
Hair growth depends on follicle health, iron/ferritin status, protein, and cycle length. Supplements help when correcting a deficiency (iron, vitamin D, zinc, biotin); collagen has modest direct evidence.
Why It Matters
Hair grows ~1 cm/month in anagen; growth complaints usually reflect shortened anagen (telogen effluvium, androgenetic loss) or breakage rather than slow growth. Ferritin below ~40–70 ng/mL is linked to shedding in women. Vitamin D deficiency correlates with alopecia. Biotin supplementation only helps when deficient — which is rare. Postpartum and post-illness shedding typically self-resolves in 6–12 months.
How to Measure
Standardized photos every 2–3 months; shedding assessment; ferritin and vitamin D via clinician if shedding is diffuse.
Biomarkers
Optimization Protocol
Correct deficiencies first: iron (if ferritin low, with vitamin C), vitamin D3 to sufficiency. Collagen peptides 10–15 g/day have modest RCT support for hair metrics. Protein 1.2+ g/kg/day. Minimize heat/chemical damage. Sudden diffuse shedding: investigate triggers (illness, weight loss, medications) 2–3 months prior.
Lifestyle Levers
- •Adequate protein daily
- •Iron-rich foods or repletion if low
- •Gentle handling, minimal heat styling
- •Stress management (telogen effluvium driver)
- •Sleep quality
Supporting Supplements
MSM
MSM provides sulfur for keratin cross-linking with preliminary human data suggesting improved hair thickness and appearance.
Vitamin D
Correcting vitamin D deficiency supports hair cycling; deficiency is associated with alopecia, but extra D beyond sufficiency has no growth benefit.
Collagen (Hydrolyzed)
Hydrolyzed collagen provides amino acids and bioactive peptides with modest RCT support for improved hair metrics over 3–6 months.
Biotin (Vitamin B7)
Biotin supports hair growth only when a true deficiency exists; for the vast majority of people, supplementation does not accelerate growth.
Iron
Iron repletion supports hair growth when ferritin is low — the single most impactful nutritional fix for diffuse shedding in premenopausal women.
Supporting Research
Frequently Asked Questions
Typical Timeframe
3–6 months minimum — hair cycles are slow.
Research Summary
My Notes
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.