Minerals
Evidence: strong_human
Iron is essential for hemoglobin (oxygen transport), myoglobin (muscle oxygen storage), cytochrome enzymes (electron transport chain — Complexes I, II, III, IV), cytochrome P450 enzymes (drug/hormone metabolism), catalase (H2O2 decomposition), ribonucleotide reductase (DNA synthesis), and aconitase (Krebs cycle). Iron bisglycinate (Ferrochel) uses amino acid chelation to bypass the normal DMT1/ferroportin pathway, instead being absorbed intact via PepT1 transporter. This mechanism avoids the GI side effects of ionic iron (free Fe2+ generates hydroxyl radicals via Fenton reaction in the gut lumen) and is not inhibited by phytates, tannins, or calcium.
Standard: 25-36mg elemental iron (as bisglycinate) daily for deficiency correction
Loading: Every other day dosing may optimize absorption (hepcidin rebound effect)
Maintenance: Discontinue when ferritin normalizes (50-150 ng/mL) unless ongoing losses
Administration: oral
Timing: On empty stomach or with vitamin C for absorption. Alternate day dosing (every other day) may be superior due to hepcidin cycling. Separate from calcium, zinc, tea, coffee by 2+ hours.
Duration: Until ferritin >50 ng/mL, then reassess (typically 3-6 months). Not for ongoing supplementation unless chronic blood loss.
ALWAYS test before supplementing — iron is the only common supplement where more is NOT better and excess causes direct harm (oxidative stress, organ damage). Required labs: serum ferritin, serum iron, TIBC, transferrin saturation. Ferritin <30 ng/mL confirms deficiency; <50 ng/mL is suboptimal for performance. The alternate-day dosing protocol (Moretti et al.) is evidence-based: hepcidin rises 24h after iron intake, blocking absorption the next day. Menstruating women, endurance athletes, and vegetarians are highest-risk populations. Ferritin >300 ng/mL warrants investigation for hemochromatosis.
Ferrochel (iron bisglycinate chelate, Albion Minerals) is the gold standard with GI tolerability far superior to ferrous sulfate. Iron protein succinylate (IPS) and polysaccharide iron complex are alternatives. NEVER use ferrous sulfate if bisglycinate is available — equivalent efficacy with far fewer side effects. Brands: Thorne Iron Bisglycinate, NOW Iron Bisglycinate, Solgar Gentle Iron.
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