Is Iron Best at Night? Maximizing Absorption for Better Health

December 25, 2025 •

4 min read

Recent studies in iron-deficient women showed that taking an iron supplement in the morning resulted in 37% higher iron absorption compared to the same dose taken in the afternoon. This evidence suggests that for most people, the morning is the optimal time for dosing, contradicting the notion that taking iron at night is best for absorption.

Quick Summary

Despite popular beliefs, research indicates that morning is the best time for taking iron supplements for maximum absorption. Factors like stomach acidity, the hormone hepcidin, and dietary interactions influence iron uptake throughout the day. Understanding these variables is key to optimizing your iron intake and improving overall health.

Key Points

Morning is Optimal: Taking iron in the morning maximizes absorption due to lower hepcidin levels and higher stomach acidity.
Hepcidin's Role: The hormone hepcidin suppresses iron absorption and is naturally lowest upon waking, making morning the best time for uptake.
Alternate-Day Dosing: For some, taking iron every other day can be more effective than daily dosing, as it allows hepcidin levels to normalize.
Enhance with Vitamin C: Pairing iron supplements with a source of Vitamin C can significantly increase absorption.
Avoid Inhibitors: Substances like calcium, coffee, and tea can block iron absorption and should be avoided for at least two hours.
Nighttime for Side Effects: Individuals with gastrointestinal sensitivity can take iron at night with a small snack to improve tolerability, though absorption may be lower.
RLS Relief: Taking iron at night may be particularly beneficial for those with Restless Legs Syndrome (RLS), a condition linked to iron deficiency.

Why Morning is Best for Iron Absorption

For many years, guidance on when to take iron supplements was based on convenience or minimizing gastrointestinal side effects. However, recent scientific evidence points to the morning as the most effective time for maximizing absorption. The primary reasons for this are related to your body's natural rhythms and internal chemistry.

The Role of Hepcidin and Stomach Acidity

One of the most significant factors influencing iron absorption is the hormone hepcidin.

Hepcidin levels are lowest in the morning: Hepcidin is a master regulator of iron absorption and storage. Its levels are naturally lower in the morning, which means the body's iron gate is more open to absorbing the supplement you take.
Iron intake increases hepcidin: A large dose of iron, such as that from a supplement, causes hepcidin levels to rise for up to 24 hours, which then suppresses further iron absorption. Taking iron at night would cause hepcidin to be high the next morning, inhibiting absorption. Spacing out doses, such as taking a supplement every other day, can also maximize absorption by giving hepcidin levels a chance to fall.
Stomach acid is higher in the morning: Iron requires an acidic environment to be absorbed properly. Stomach acid levels tend to be highest upon waking, creating the ideal conditions for your body to process the iron from a supplement efficiently.

Alternate-Day Dosing: The Next Level of Optimization

For even better results, some studies suggest that taking iron supplements every other day may improve absorption more than daily dosing. By allowing a day for hepcidin levels to drop back down, the body is primed to absorb the next dose more effectively. For some, this method is also associated with fewer gastrointestinal side effects. A single, high dose every other day can lead to greater total iron absorption over time compared to smaller daily doses. Always consult with a healthcare provider before altering your prescribed supplement schedule.

Foods and Drinks to Avoid

To truly maximize your iron absorption, it's not just about timing but also about what you consume around that time. Several substances can significantly inhibit iron absorption.

Calcium: Found in dairy products like milk, yogurt, and cheese, calcium can compete with iron for absorption in the gut.
Coffee and Tea: These beverages contain tannins and polyphenols that bind to iron, forming a compound that your body cannot absorb. One study found that taking iron with coffee cut absorption by 54%.
High-Fiber Foods: Foods like whole grains, beans, and lentils contain phytates that can inhibit iron absorption.

Can Taking Iron at Night Ever Be Beneficial?

While not ideal for maximizing absorption, there are specific situations where taking iron at night might be the preferred or only option. Most notably, individuals who experience significant gastrointestinal discomfort when taking iron on an empty stomach often find relief by taking it with a small snack in the evening or before bed. In these cases, the benefit of consistent intake and better tolerability outweighs the reduced absorption. For those with iron deficiency who also suffer from Restless Legs Syndrome (RLS), some research suggests that nighttime supplementation may help alleviate symptoms and improve sleep quality.

Comparison Table: Morning vs. Nighttime Iron Supplementation


Feature	Morning Dosing	Nighttime Dosing
Absorption Rate	Higher due to lower hepcidin and higher stomach acid.	Lower, potentially reduced by 20–40%.
Gastrointestinal Effects	Increased risk of nausea or cramps on an empty stomach.	Lower risk of stomach upset if taken with a small snack.
Consistency	Can be easier to remember by anchoring to a morning routine.	May be easier for those who forget morning doses.
Restless Legs Syndrome	Less direct impact on evening RLS symptoms.	May help alleviate RLS symptoms and improve sleep quality.
Interaction with Food	Must be taken away from breakfast and coffee for best results.	Must be taken with a small, low-calcium snack if stomach is sensitive.

Conclusion

In summary, the scientific consensus strongly favors taking iron supplements in the morning for maximum absorption. This is primarily due to lower levels of the iron-regulating hormone hepcidin and higher stomach acidity upon waking. While taking iron at night is possible and may be necessary for some individuals who experience stomach upset or have specific conditions like RLS, it is less efficient for increasing iron levels. For optimal results, combine morning supplementation with a vitamin C-rich drink and avoid inhibitors like calcium and caffeine. For personalized advice, and especially if you have a medical condition affecting iron absorption, always consult your healthcare provider or a registered dietitian. Learn more about iron supplementation from the National Institutes of Health.

How to Optimize Your Iron Supplement Routine

To create the most effective supplementation schedule for your needs, follow these steps:

Time it Right: Take your iron supplement first thing in the morning on an empty stomach, at least 30 minutes to an hour before breakfast.
Add Vitamin C: Drink a glass of orange juice or take a vitamin C supplement to significantly boost iron absorption.
Avoid Inhibitors: Wait at least two hours after taking your supplement before consuming milk, cheese, coffee, or tea.
Consider Alternate Days: Discuss with your doctor whether an every-other-day dosing schedule is appropriate for you to maximize fractional iron absorption.
Listen to Your Body: If you experience severe stomach discomfort, try taking your supplement with a small, bland, and low-fiber snack in the evening. Consistent intake is better than stopping altogether due to side effects.

Following these guidelines will ensure you get the most out of your iron supplement and effectively address iron deficiency.

Frequently Asked Questions

For most people, it is better to take iron supplements in the morning. Research shows that iron absorption is highest in the morning due to the body's lower levels of the hormone hepcidin and higher stomach acidity upon waking.

The best way to take an iron supplement is on an empty stomach, accompanied by a source of Vitamin C (like orange juice), and at least two hours away from iron-inhibiting foods and beverages like dairy, coffee, and tea.

Some people take iron at night to mitigate gastrointestinal side effects like nausea and stomach cramps, as taking it with food can help alleviate discomfort. Additionally, individuals with Restless Legs Syndrome (RLS) may find nighttime supplementation beneficial.

While iron deficiency itself can cause sleep disturbances, taking an iron supplement at night typically does not interfere with sleep. Some evidence even suggests it may improve sleep quality for those with RLS.

Hepcidin is a hormone that regulates systemic iron balance by controlling iron absorption. An iron supplement dose raises hepcidin levels, which can suppress subsequent iron absorption. Hepcidin is naturally lowest in the morning, making it the most optimal time for absorption.

Emerging research suggests that alternate-day dosing can be more effective for some people, as it allows hepcidin levels to fall between doses, leading to a higher fractional absorption over time. It is best to discuss this strategy with a healthcare professional.

You should wait at least two hours after taking your iron supplement to consume coffee or tea. The compounds in these drinks can significantly reduce iron absorption.