Best Iron Supplements for Perimenopause: Managing Fatigue and Heavy Periods
Find the best iron supplements for perimenopause. Understand which forms are easiest to tolerate and how to tell if you actually need one.
Iron and Perimenopause: The Connection
Heavy and irregular periods are among the most common experiences in perimenopause, and they can lead to significant iron loss over time. Iron is essential for producing haemoglobin, the protein in red blood cells that carries oxygen around the body. When iron stores become depleted, fatigue, brain fog, breathlessness on exertion, and pale skin can follow. These symptoms overlap heavily with other perimenopause complaints, which makes iron deficiency easy to miss. A blood test measuring ferritin, the stored form of iron, is the most reliable way to confirm whether low iron is contributing to how you feel.
Forms of Iron: Which Absorbs Best
Iron supplements come in several forms. Ferrous sulphate is the most commonly prescribed and generally the cheapest, but it frequently causes constipation, nausea, and an upset stomach. Ferrous fumarate and ferrous gluconate are alternatives with similar absorption but sometimes slightly better tolerability. Iron bisglycinate, also called ferrous bisglycinate or gentle iron, is chelated to an amino acid and typically absorbs well while causing far fewer digestive side effects. It tends to cost more but is worth the price if you have struggled with conventional iron before. Liquid iron supplements are another option for those who cannot tolerate tablets.
Dose: More Is Not Always Better
Standard therapeutic doses for iron deficiency anaemia are usually in the range of 100 to 200 mg of elemental iron per day, divided across two doses. However, recent research suggests that taking iron on alternate days rather than every day can improve absorption and reduce side effects, because the gut has a regulatory mechanism that temporarily blocks iron uptake after a large dose. If you are supplementing to maintain levels rather than treat diagnosed deficiency, a lower daily dose of around 14 to 18 mg, which is closer to the dietary reference value, is usually sufficient. Always confirm the appropriate dose with your GP based on your blood test results.
Maximising Absorption
Taking iron with vitamin C significantly enhances absorption. A glass of orange juice, a handful of strawberries, or a dedicated vitamin C tablet alongside your iron supplement helps convert iron into a form the gut absorbs more readily. Avoid taking iron at the same time as calcium supplements, antacids, or dairy products, as calcium blocks iron absorption. Tea and coffee also interfere with iron uptake if consumed within an hour either side of your supplement. Taking iron on an empty stomach increases absorption but also increases digestive side effects, so if your stomach is sensitive, taking it with a small amount of food is a reasonable trade-off.
Signs You May Not Actually Need Iron
Not every woman in perimenopause needs an iron supplement. If your periods have become lighter or less frequent, iron loss may actually be decreasing. Supplementing with high-dose iron when your levels are already normal is not beneficial and can cause oxidative stress and digestive problems. Iron overload is a genuine concern for some women, particularly those with hereditary haemochromatosis. This is why a blood test before starting iron supplementation is important rather than guessing based on symptoms alone. Once you have confirmed a deficiency, supplementing is entirely appropriate and often makes a noticeable difference to energy levels within six to eight weeks.
Food Sources to Prioritise Alongside Supplements
Dietary iron comes in two forms: haem iron from meat, fish, and poultry, which the body absorbs efficiently, and non-haem iron from plant foods such as lentils, beans, tofu, seeds, and fortified cereals, which absorbs less efficiently but still contributes meaningfully to intake. Eating a varied diet with plenty of these foods reduces the amount of supplemental iron needed. If you follow a vegetarian or vegan diet, your risk of iron depletion during perimenopause is somewhat higher, and regular ferritin checks are sensible. Using PeriPlan to track energy levels and fatigue patterns over time can help you notice trends that prompt a timely conversation with your doctor.
Monitoring Progress and Adjusting
Once you start an iron supplement for confirmed deficiency, a follow-up blood test after three months is standard practice to check whether ferritin is recovering. It typically takes three to six months of consistent supplementation to fully replenish stores, even if you start feeling better sooner. Once levels are restored, your GP will advise whether to continue at a lower maintenance dose or stop and rely on diet. If your periods have stopped or your ferritin remains persistently low despite supplementation, further investigation may be needed to rule out other causes of iron loss, such as gut bleeding or absorption issues.
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