How Long Do Iron Supplements Take To Work?

November 8, 2017


How Long Do Iron Supplements Take To Work?

Table of Contents [ Hide ]


Mineral supplements are no longer a stranger to most of us. Since iron deficiency is a controversial phenomenon in the modern society, iron supplements have been receiving a great deal of attention. If you have been taking iron supplements, you may wonder “how long do iron supplements take to work?” If you still consider taking this supplement, read on. This article will provide you adequate background knowledge on iron supplements and at the same time answer the question “how long do iron supplements take to work?

What are iron supplements?

How long do iron supplements take to work? To answer this question, we first need to take a look at what iron supplements are.

So, what is iron?

Iron is one of the important minerals in human. Hemoglobin, which consists of approximately two-thirds of the iron in the body, is the organ that helps transport oxygen from the lungs to the rest of the body. Iron is the main factor that our blood is red. It also converts blood sugar into energy, providing “food” for our muscles and reducing resting time after intense exercise. Last but not least, iron is part of the renewing process, producing fresh and healthy hair, nails and skins, and at the same time, supports the immune system battle against harmful external factors.

Iron is so important that once you do not supply it enough for the body, serious reactions appear. One of these is anemia, a condition in which the red blood cells are insufficient, resulting in paleness and exhaustion.

Without a proper diet, iron deficiency is likely to occur. Therefore, iron supplements were invented to act as a second source of irons for the body. These products are available in many forms, such as tablets, liquid, capsule, powder, and syrup. Iron supplements are often prescribed for pregnant women, people who diagnosed with anemia, and athletes. Other uses of iron supplements include depression, fatigue, and blood loss during menstruation.

For more information and better insights on iron supplements, please read the following article HOW TO BUY THE BEST IRON SUPPLEMENT FOR DAILY CONSUMPTION.


Do you need to take iron supplements?

How important are irons to us? Our body gets iron from food. Eggs, red meat, seafood, cereals, and other vegetables such as pumpkin seeds, and beans are the main iron sources for our body. However, if your daily diet is not in the balance, there is a high chance that you do not provide enough iron for your body. In fact, according to the World Health Organization, iron deficiency has long been rife on a global scale [1].

Sometimes, small and slow bleeding can cause iron deficiency without our awareness.  Doctors can detect the amount of iron deficiency and decide whether iron supplements are required. Some other conditions require iron supplements. These include:

  • Burns
  • Stomach problems
  • Hemodialysis
  • Having an ulcer
  • Gastrointestinal disorder
  • Antacids surplus
  • Kidney failure

Primarily, women need more iron since they have menstruation every month. Pregnant or breastfeeding women also demand a higher amount of iron, since iron plays an important role in forming the placenta, an essential part of the womb. Infants that are receiving breast milk may also target of iron deficiency. Last but not least, if you do exclude meat and milk products from your daily diet, then you may need to take iron supplements due to the fact that the body can’t take the type of iron in plants as effectively as the one in meat.

How do you know if you’re iron deficient?

Most of us are unaware of our body’s conditions until signs and symptoms appear. That happens to people with anemia too. They normally are short of breath, have fast heartbeats and cold hands. Some people start to have hair loss, sore tongue, and difficulty in swallowing. Since our body needs sufficient oxygen to function properly, people with anemia find it hard to work physically. If you feel tired or dizzy out of the blue, don’t hesitate to see your doctor. With just a simple blood test, you will know your body condition and how much iron you need to contribute to it.

If you find yourself in the middle of these mentioned indications, most likely your doctor will ask you to take iron supplements.

How long do iron supplements take to work?

This question has long been one of the top questions on most health blogs or websites. It’s understandable that we in a hurry to find out whether the purchased supplements are actually making us any better. Iron supplements will start to work within the first week. However, it’s a rather complex phenomenon since the supplement effectiveness is based on several factors. Below are the factors that will contribute or prevent iron absorption thus shortening or lengthening the period of iron supplements to work.


It is important to know your required dosage before you ask yourself how long it takes for iron supplements to work.

How much do you need to take iron supplements? According to the Office of Dietary Supplements [2], infants and children up to 13 years old are not allowed to take more than 40 mg per day. This is the maximum dose of iron supplements for children under 13 years old without the risk of iron excess which can lead to side effects. Some signs of too much iron include stomach cramps, numbness, muscle pain, and backache.

Children from 13 to 19 years old  should take up to 45 mg daily. This limit is also applied to pregnant and breastfeeding mothers; however, mothers should be cautious with their supplement dosage. It’s better for them to discuss before with their doctors on how and how much they should take iron supplements. Adults can take somewhere between 150 to 300 mg of iron per day.

Knowing your dosage is extremely important since it is the amount of iron supplements your body needs to work. If you take less than the requirement, you will notice no change. On the other hand, taking jumbo-dosages is not a good idea either.


Absorption Rate

Even though iron has long been considered a vital element for the body, asking it to absorb a significant amount of iron at once is very tricky. The science behind it is your body needs time to gain appropriate amounts of iron as much as it needs to lose weight or take up water. Drinking 8 cups of water at the same time won’t do any good for your cells. The same for taking iron supplements.  For iron supplements to work, patients should spread their intakes throughout the day. Take it easy!

The quality of Supplements

There are many concerns regarding iron supplements’ quality. In most countries, purchasing of vitamins and minerals are restricted and controlled by the government. When complaints and health claims appear, the trade commission will come to the manufactures and check to make sure they follow the rules, and there is no inconsistency between the label and actual contents. That means the trade commission act on customers’ behaves only after something has happened. They surely don’t have enough time and human resource to go around and examine any types of supplements on the market.

Therefore, you should only choose supplements from reputable companies or providers, since the supplements’ quality directly affects how long iron supplements take to work. The good quality ones will produce a better absorption rate than the bad ones.


Do you consume iron supplements with dairy products? If your answer is yes, then it is the bad news for you. Dairy products, including milk, yogurts, cheese, and ice-cream, are calcium-rich food. Calcium is known as the main factor interfering with the absorption process of iron. A recent study published on “Milk and Milk Products in Human Nutrition” in 2010 shows that infants who ingest large amounts of cow’s milk have a higher possibility of iron deficiency than those who don’t [4]. Another study claims that dairy products can cause reduction of iron absorption by 50 to 60 percent [5].

Some other foods that affect iron absorption including:

  • Tea or coffee
  • Products that contain caffeine
  • Tofu or products from soybeans
  • Dietary fiber
  • Phytates is often found in beans and whole grains
  • Polyphenols, a plant-based compound usually found in wine, fruits, vegetables, and nuts.

These foods will block your body from extracting iron from iron supplements. You can also take in minimal amounts at least 2 hours after consuming iron supplements to make sure they will work. However, it is better to take it when your stomach is empty because your body will absorb iron better in this condition.

Other supporting elements

Although iron supplements will work better if taking when your stomach is empty, however some doctors suggest that iron will be absorbed better by the body when vitamin C comes in hand. A glass of orange juice rather than water will not only boost our immune system but also help the body to consume iron better. Lemon, kiwi, berries and citrus fruits are advised to take together with iron supplements. Other vitamin C vegetables include broccoli, peppers, and tomatoes.

Another element that enhances the absorption rate of iron is the balance level of heme iron and non-heme iron. So what are the differences between these two? In animals, iron is attributed to proteins called heme proteins, thus called heme iron. In plants, this attachment doesn’t exist; therefore iron in plants is called non-heme iron. Heme iron is absorbed in the rate of 15 to 35 percent, whereas the rate in non-heme iron is only 2 to 20 percent. Our bodies need both non-heme iron and heme iron, and heme iron can help increase the absorption rate of non-heme iron. That can explain why vegetarians or vegans need are subjected to iron deficiency since their bodies take many non-heme irons from plants.

Preventing elements

Antacids and H2-antagonists

During the digestion of food, your stomach releases acid to help smooth out the process and kill harmful bacteria. Since the acid is destructive, the body has a barrier which prevents the stomach from being eroded. In some people, this barrier does not function as it should be, causing damage to the stomach and thus leading to cancer. To prevent this, antacids and H2-antagonists are prescribed. These two elements are proved to be effective, leaving no side effects for users. However, if you take iron supplements together with antacids or H2-antagonists (typically found in forms of cimetidine, ranitidine, famotidine, or nizatidine), the absorption rate of iron supplements may decline.


Tetracycline antibiotics are often used to battle against infections of the skin, intestines, respiratory tract and other body system infected by bacteria. When taking in with iron supplements, these antibiotics prevent your body from absorbing iron, thus leading to the drop of the supplements’ effectiveness.  You should also avoid other forms of tetracycline antibiotics, including ciprofloxacin, enoxacin, norfloxacin, sparfloxacin, and grepafloxacin.


Dolutegravir is a recently developed medicine for people diagnosed with HIV. The body is unable to absorb iron if you take dolutegravir at the same time.


The thyroid gland, located at the base of your throat, is responsible for producing hormones that control your metabolism and body’s energy. This organ regulates breathing, heart rate, body weight, muscle strength, body temperature, and menstrual cycles. A malfunctioned thyroid will be treated by levothyroxine. Levothyroxine, however, is one of the main causes of decreasing the absorption rate of iron supplements.      

How severe your condition is

To understand the iron deficiency, your doctor will run a complete blood count (CBC) [3] to measure all of the fundamentals of the blood, including:

  • Red blood cells
  • White blood cells
  • Hemoglobin
  • Hematocrit
  • Platelets

A healthy hematocrit range is from 34.9 to 44.5 % for adult women and 38.8 to 50 % for adult men. The normal hemoglobin span is from 12 to 15.5 gram per deciliter for adult women and 13.5 to 17.5 grams per deciliter for adult men. People diagnosed with anemia have relatively low levels of both hematocrit and hemoglobin. Additionally, the red blood cells are smaller than normal red blood cells.

Depending on how low it is, you will know your iron dosage and how long iron supplements take effect. If your iron deficiency is severe, it will take longer for the supplements to function.

Cause of Deficiency

There are many causes of iron deficiency. With each cause, there is a possible solution for it. Do you have anemia because of genetic situation? Is it a side effect of your treatment? Do you have a poor iron diet? Knowing your cause will help you understand your situation and dosage you have to take. Iron supplements will take to work more effectively if you take them in the right way, knowing your own need and reason.

Types of iron supplements

There are two common types of iron: ferric and ferrous iron. Since ferrous iron is easier to absorb, most of the iron supplements enclose ferrous iron. However, if you do not pay attention to the ingredient and also don’t know the fact, you may be tricked by providers who will sell you supplements with ferric iron which takes longer to absorb and at the same time is less effective.

Moreover, iron supplements vary in many forms, but typically they are: tablets, capsules, liquids, drop, and so on. Each type has its unique and suitable characters for different patients. The absorption rate, therefore, differs depending on types of iron and iron supplement forms you take.

How long will iron supplements resolve in my stomach

It takes 20 to 30 minutes for iron supplements to dissolve in the stomach. Iron from food or supplements will be absorbed in the duodenum, the small intestine. It will then travel to your stomach where stomach acid will transform it into a type that is easier to absorb. Why do you need to know the process of absorption of iron supplements?

Because once you understand how the process works, you will be more mindful about how to maximize the effect of iron intake. Some supplements suppliers claim that iron supplements have a slow release mechanism, which means you will have to wait for the sugar coating around your iron pills to dissolve. This process takes time, thus decelerating the absorption rate of iron supplements.

When you consume iron supplements matters

What is the best time of the day to take iron supplements? Since your body absorbs iron better when your stomach is empty, it is better to take them after or before eating at least 2 hours. It is also good if you use orange juice instead of water as vitamin C accelerates the absorption of iron. In case your stomach can’t bear raw iron supplements, you can take it right before or after eating. However, keep in mind to stay away from calcium-rich food such as milk or cream, since they will prevent iron supplements to work.



Spoiled iron supplements are fraught with pitfalls. Therefore, you should store them in a cool, dry place, away from direct heat or light. This will help maintain your tablets’ value as well as the iron supplements’ effectiveness, thus increasing the absorption rate.

Bottom Line

So how long do iron supplements take to work? Depending on your own symptoms and the factors above, it may take two to three months to fill up your iron deficiency by using supplements. Normally, doctors will recommend you to continue taking iron supplements even after the level of iron in your body is balanced up to 6 months. Therefore, it is imperative to monitor your health condition and keep track with your iron deficiency to make sure that you provide enough this vital compound to your body.  

Find this article helpful? LIKE and SHARE with your friends to receive healthy tips!

Related Post