Mineral
Iron
Iron deficiency is remarkably common during perimenopause due to heavy bleeding, and correcting it can dramatically improve energy, brain fog, and mood when you're actually deficient. The evidence for supplementation is strongest when blood tests confirm low levels — excess iron accumulates over time and can cause oxidative damage. After menopause, iron needs drop significantly since monthly blood loss stops, making testing essential before supplementing.
30-second summary
Iron deficiency is remarkably common during perimenopause due to heavy bleeding, and correcting it can dramatically improve energy, brain fog, and mood when you're actually deficient. The evidence for supplementation is strongest when blood tests confirm low levels — excess iron accumulates over time and can cause oxidative damage. After menopause, iron needs drop significantly since monthly blood loss stops, making testing essential before supplementing.
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Overall: Mixed evidence
Randomised controlled trials
Multiple randomized trials show iron supplementation effectively improves energy and cognitive function in iron-deficient women, though most studies focus on younger populations.
Large population studies consistently link iron deficiency with fatigue, depression, and cognitive difficulties, particularly in women with heavy menstrual bleeding.
Systematic reviews confirm iron supplementation improves fatigue and cognitive performance in iron-deficient individuals, with benefits appearing within 4-6 weeks.
Menopause-specific trials
Limited studies specifically examine iron in perimenopausal women, though observational data shows deficiency rates spike during heavy bleeding phases.
What we do not know
Most iron studies focus on severe anemia rather than mild deficiency common in perimenopause. We lack specific dosing guidelines for perimenopausal women with heavy bleeding. The optimal form of supplemental iron for this population hasn't been established in trials. Long-term safety data for iron supplementation in postmenopausal women is limited. We don't know the threshold at which stored iron becomes harmful in older women.
How it is used
Common dose range
Only supplement if deficient — as directed by blood test results
Notes on dosing
Never supplement iron without confirming deficiency via blood test. Take on empty stomach with vitamin C.
Get it from food first
Food sources are better absorbed than most supplements and come with co-factors that support the same pathways. If you eat two or three of these consistently, you may not need a supplement at all.
beef liver
3 oz
highest bioavailable source
lean beef
3 oz
easily absorbed heme iron
oysters
3 oz
excellent absorption
dark chicken meat
3 oz
more iron than white meat
sardines
3 oz
convenient canned option
spinach
1 cup cooked
pair with vitamin C for absorption
white beans
1 cup
plant-based option
dark chocolate
1 oz
70% cacao or higher
Mediterranean with meat
combines heme iron sources with vitamin C-rich vegetables that enhance absorption
Traditional eating patterns
organ meats and nose-to-tail eating provide concentrated iron in bioavailable forms
What depletes Iron
Calcium supplements or dairy consumed with iron-rich meals can block absorption by up to 60%. Tannins in tea and coffee significantly reduce iron uptake when consumed within an hour of meals. Phytates in whole grains and legumes bind iron, though this effect is reduced by soaking, sprouting, or fermenting. Antacids and proton pump inhibitors reduce stomach acid needed for iron absorption.
Interactions and cautions
No significant interactions noted at recommended doses.
Rose bottom line
"Your heavy periods may be quietly draining your iron stores, and that exhaustion you're feeling could have a straightforward fix. Get your ferritin, iron, and total iron-binding capacity tested — knowledge is power here, and the right answer depends entirely on what those numbers show."