Raising hemoglobin comes down to giving your body the raw materials it needs to build healthy red blood cells, primarily iron, but also key vitamins like B12 and folate. Healthy hemoglobin ranges are 13.2 to 16.6 g/dL for men and 11.6 to 15 g/dL for women. If your levels are below that, a combination of dietary changes, smart supplement use, and attention to absorption can make a real difference over several weeks.
Eat More Iron-Rich Foods
Iron is the core building block of hemoglobin, and the type of iron you eat matters. Heme iron, found in animal-based foods, is absorbed significantly more efficiently than non-heme iron from plant sources. The best heme iron sources include beef (especially liver), chicken, turkey, pork, and fish like tuna and sardines. If you eat meat, even small servings added to meals can meaningfully boost your intake.
Non-heme iron is found in beans, lentils, tofu, spinach, fortified cereals, and whole grains. It’s harder for your body to absorb, but you can dramatically improve uptake by pairing these foods with vitamin C (more on that below). If you’re vegetarian or vegan, leaning heavily on legumes, dark leafy greens, and fortified foods is essential.
One thing to watch: cow’s milk contains very little iron, only about 0.1 to 0.2 mg per cup. If milk or dairy makes up a large portion of your diet (or your child’s), it can crowd out iron-rich foods without contributing much iron itself.
Boost Absorption With Vitamin C
Vitamin C is the single most effective dietary factor for increasing non-heme iron absorption. It works by converting iron into a form your gut can take up more easily. Practical pairings look like squeezing lemon over lentil soup, eating strawberries with fortified cereal, or having bell peppers alongside a bean dish. Oranges, tomatoes, broccoli, and kiwi are all strong sources.
Pork and other animal proteins also enhance iron absorption from plant foods when eaten in the same meal. Adding even a small amount of meat to a plant-heavy dish can increase how much iron you actually absorb.
Avoid These Around Iron-Rich Meals
Several common foods and drinks actively block iron absorption, and timing them away from your iron-rich meals or supplements can make a noticeable difference.
- Tea and coffee: Polyphenols in these drinks bind to iron and prevent absorption. Black tea is especially inhibitory, but coffee, cocoa, and even some herbal teas like peppermint have a similar effect. Try to wait at least an hour after an iron-rich meal before drinking them.
- Calcium and dairy: Calcium inhibits both heme and non-heme iron absorption, reducing it by roughly 18 to 27%. Calcium supplements and milk or cheese have similar effects. If you take a calcium supplement, take it at a different time of day than your iron.
- Eggs: Egg yolk contains compounds that reduce iron absorption from other foods in the same meal. This doesn’t mean you should avoid eggs entirely, just be aware that pairing them with your highest-iron foods isn’t ideal.
- Soy protein: Isolated soy protein dramatically reduces iron absorption due to phytic acid and specific proteins it contains. If soy is a staple in your diet, try not to rely on it as your primary iron source.
Phytates, found naturally in whole grains, nuts, seeds, and legumes, also bind to iron. Soaking, sprouting, or fermenting these foods breaks down phytates and improves absorption.
Consider an Iron Supplement
If diet alone isn’t enough, iron supplements are the most common next step. The three main types differ in how much usable (elemental) iron they deliver per tablet:
- Ferrous sulfate (dried form): 325 mg tablet provides about 120 mg of elemental iron
- Ferrous fumarate: 300 mg tablet provides about 99 mg of elemental iron
- Ferrous gluconate: 325 mg tablet provides about 39 mg of elemental iron
The elemental iron number is what actually matters for your body, and it’s listed on the Supplement Facts panel so you don’t have to calculate it yourself. Many iron-only supplements deliver 65 mg of elemental iron or more per dose. Your doctor can help determine the right amount based on how low your levels are.
Iron supplements are best absorbed on an empty stomach, but that’s also when they’re most likely to cause side effects. If you experience stomach problems, taking your supplement with a small snack or meal can help, though absorption will be slightly lower.
Managing Side Effects
Constipation is the most common complaint. Increasing fiber from fruits, vegetables, and whole grains, staying well hydrated, and getting regular physical activity can all help. If diarrhea is the issue instead, focus on drinking plenty of fluids to stay hydrated. For nausea or stomach discomfort, eating smaller, more frequent meals and taking your supplement with food often eases symptoms. Dark or black stools are normal with iron supplements and not a cause for concern on their own.
Don’t Forget B12 and Folate
Iron gets most of the attention, but your body also needs vitamin B12 and folate to produce properly functioning red blood cells. Without enough of either, your body makes red blood cells that are too large and can’t carry oxygen efficiently, leading to low hemoglobin even when iron levels are fine.
Good sources of B12 include beef, chicken, fish, eggs, milk, cheese, and fortified cereals. Since B12 is found almost exclusively in animal products, vegans need to rely on fortified foods or a supplement. Folate is abundant in broccoli, spinach, asparagus, oranges, strawberries, lentils, and enriched grain products like bread and pasta. Most people get enough folate through a varied diet, but pregnancy, certain medications, and digestive conditions can increase your needs.
How Long It Takes to See Results
Raising hemoglobin is not an overnight process. With consistent iron-rich eating plus supplements, it typically takes several weeks to see a measurable increase in levels. Many people start feeling less fatigued within two to four weeks, but fully replenishing your iron stores can take three months or longer. Your doctor will likely recheck your blood work after a couple of months to track progress.
If your hemoglobin is very low (generally below about 7 to 8 g/dL) or you can’t tolerate oral supplements due to side effects or poor absorption, intravenous iron infusions are an option. IV iron bypasses the gut entirely, delivers a large dose in one or two sessions, and raises levels faster than oral supplements can. This is especially useful during pregnancy, when there may not be enough time for oral iron to work, or for people with digestive conditions that prevent normal iron absorption. For extremely low hemoglobin (below about 5 g/dL), a blood transfusion may be necessary for immediate correction.
A Practical Daily Approach
The most effective strategy combines several of these steps at once. Build meals around iron-rich proteins or legumes, add a vitamin C source to each meal, and separate your coffee or tea by at least an hour. If you’re supplementing, take it at a consistent time each day, ideally apart from calcium supplements or dairy-heavy meals. Track your energy levels and follow up with blood work to confirm your levels are moving in the right direction.