TempoLife › Features › Supplement reference: dose, evidence and forms › iron
Iron
What Iron is, what the NIH ODS fact sheet says the evidence supports, typical doses, timing, and the cautions that come with it.
Supplements are not medicines and this page is not medical advice. Doses that help one person can harm another — with medicines, kidney or liver conditions, pregnancy, or before surgery, talk to a clinician before starting anything. More is not better.
What it is
A mineral at the core of haemoglobin; moves oxygen in the blood.
What the evidence supports
ODS: treats iron-deficiency anaemia and prevents deficiency in at-risk groups.
Dose and timing
RDA: men 8 mg, women 19-50 18 mg, pregnancy 27 mg per day. Absorbs best on an empty stomach; with vitamin C it absorbs better; tea/coffee and calcium block it.
Cautions
Supplement only when deficient — excess iron is stored and can harm. Constipation is common; discuss forms with a pharmacist.
Interactions are the hidden risk: supplements can change how medicines work and vice versa. Give your clinician the full list before anything else.
Source: NIH Office of Dietary Supplements — Iron fact sheet · checked 2026-09-03
Frequently asked questions
What does Iron do?
A mineral at the core of haemoglobin; moves oxygen in the blood.
Does Iron work?
ODS: treats iron-deficiency anaemia and prevents deficiency in at-risk groups.
How much iron should I take?
RDA: men 8 mg, women 19-50 18 mg, pregnancy 27 mg per day. Absorbs best on an empty stomach; with vitamin C it absorbs better; tea/coffee and calcium block it.
Is Iron safe?
Supplement only when deficient — excess iron is stored and can harm. Constipation is common; discuss forms with a pharmacist. And the standing rule: tell your clinician everything you take — supplements interact with medicines.
Creatine
Studied doses: 3-5 g per day; loading protocols use about 20 g/day in 4 doses for 5-7 days.
Magnesium
RDA: men 400-420 mg, women 310-320 mg per day.
Vitamin D
RDA: 600 IU (15 mcg) to age 70, then 800 IU (20 mcg). UL 4000 IU.
Omega-3s (EPA/DHA)
No RDA for EPA/DHA; ALA: men 1.6 g, women 1.1 g per day. Many products supply 250-500 mg combined EPA+DHA per day.
Melatonin
Studied doses commonly 0.5-5 mg, taken 30-60 minutes before bed.
Vitamin B12
RDA: 2.4 mcg per day.
Log it, and show it to your doctor
TempoLife keeps supplements, food and sleep in one place — a list your clinician can actually review.