Hair health (actionable notes)
Post is divided into:
1. Macronutrients
2. Micronutrients
3. General Habits
4. Optional but useful adjuncts
5. Mixed evidence
6. Marketing / Hype / Avoid list
Few disclaimers:
1. Hair is heavily genetic. Some people keep great hair doing almost nothing. Others need to manage actively.
2. For active, patterned thinning (AGA), a dermatologist visit is required.
3. Hair is metabolically non essential. If your body is under stress (low calories, low iron), it sacrifices the hair cycle first to prioritize vital organs
Macronutrients
1. Adequate calories: if in deficit, avoid more than 10-15% below maintenance
2. Adequate protein: Aim for ~1.6g/kg BW or more
Micronutrients (I've mentioned optimal values for hair health, not lab normal values)
1. Iron / ferritin: >70 ng/mL
2. TSH: 1.0-2.5 mIU/L
3. Scalp inflammation
4. Vitamin D: 50-80 ng/mL
5. Zinc: 90-110 µg/dL
6. B12: >500 pg/mL
7. Folate: >10-15 ng/mL
General habits
1. Stress / Sleep: major stressors can trigger telogen effluvium
2. Gentle hair care: heat, bleach, tight hairstyles can cause breakage/traction loss
3. Scalp hygiene: chronic dandruff/sebderm creates oxidative stress at the root; think of the scalp as "soil health"
Optional adjuncts (not foundations)
1. Ketoconazole shampoo: primarily for scalp inflammation; some evidence suggests it may help maintain density over time
2. LLLT / Red Lights: FDA-cleared, stimulates mitochondria to extend the growth phase; requires 3–6 months of consistent use
Narrow or mixed evidence
1. Microneedling: better evidence when paired with minoxidil for AGA, not needed for general hair health
2. Biotin: only helps if deficient, which is uncommon
3. Caffeine / Rosemary oil: small studies, limited clinical certainty compared to medical options
4. Collagen: indirect support at best; total protein intake is a much higher ROI
Mostly marketing
1. Hair gummies usually just expensive sugar and biotin
2. Proprietary "hair growth" blends: hide low dosages behind "secret formulas"
3. Random DHT blocking supplements: unregulated supplements with questionable safety/efficacy
4. Oils/serums without meaningful actives: most just coat the hair for shine without reaching the follicle
Summary
Most hair health content sells C/D tier stuff.
The real base is boring: calories, protein, ferritin, thyroid, micronutrient sufficiency, scalp health