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Symptoms of Iron Deficiency in Adults

pregnant mother and young boy preparing fruit for a smoothie

By Rhianna Ross, RHN

Iron deficiency isn’t common just in children; it affects adults too.

Iron deficiency, even without anemia, can cause unpleasant symptoms. 

In this article we explore the symptoms of iron deficiency in adults. 

Some of the symptoms listed below can also be caused by other nutrient deficiencies or underlying health issues. If your iron levels have been tested and are optimal, you will need to explore other possibilities. Work with your health care practitioner to investigate. 

Symptoms of iron deficiency and their severity can vary from person to person. It is also possible to be asymptomatic.

What Is Iron?

Iron is an essential mineral with many roles in the body. One key role is oxygen transport through hemoglobin. 

Hemoglobin is an iron-containing protein found in red blood cells that carry oxygen from our lungs to the rest of the body. 

Iron deficiency can cause hemoglobin levels to drop. When hemoglobin levels drop due to low iron, less oxygen makes it to our cells.

normal blood graphic showing many red blood cells, next to anemic blood graphic showing fewer red blood cells

Physical Symptoms of Iron Deficiency

Restless Legs

Tingling sensations and/or an uncontrollable urge to move the legs are symptoms of restless leg syndrome. This is an annoying health problem that is caused by iron deficiency or iron deficiency anemia. Iron is needed to make dopamine, a neurotransmitter found in the brain, which is also involved in muscle movement. When dopamine levels drop, restless legs can occur.

Note that insufficient magnesium levels may also play a role in restless legs.

Reduced Immunity 

Low iron causes a weak immune system which results in more illness and infection. Certain cells that are a part of our immune system need iron for metabolism and if iron is low, they will not create enough energy to work properly.

Craving Ice, Dirt, or Clay (Pica)

Craving ice, dirt, or clay are common symptoms of low iron, zinc, and magnesium, especially in children. While the reasons aren’t totally clear, dirt and clay are likely a source of minerals.⁠

Pale Skin

Hemoglobin gives red cells their colour. Less hemoglobin in the blood will cause skin, lips, eyelids, and gums to be pale.

Hair Loss

The lack of oxygen in the blood due to low iron can also affect the cells that stimulate hair growth. When ferritin drops below 30, there is a strong association with hair loss. Hair will likely not start to grow back until ferritin is between 50 and 70.


Muscle Weakness & Low Stamina

Reduced strength and stamina occur because iron is needed to deliver enough oxygen or energy to the muscles. The heart must then work harder to get cells the oxygen they need.

Cold Hands & Feet

Cold hands and feet, a sign of poor circulation, are also a symptom of iron deficiency and anemia. Low iron causes less oxygen to be carried to the cells, tissues, and organs of the body, leading to poor circulation.⁠ 

Dizziness, Fast Heartbeat, Rapid Breathing

Dizziness, rapid or irregular heart rate, or feeling out of breath are signs of iron deficiency or anemia. When your iron is low, hemoglobin can’t carry adequate oxygen on your red blood cells to your brain and heart.

To compensate, breathing rate may increase and cause shortness of breath.

This is also why heart palpitations can occur. Our heart works harder trying to move blood around the body faster to provide cells with more oxygen.

Symptoms Related to Brain Function

Iron is needed to maintain proper brain function. Iron is involved in the production of important neurotransmitters including dopamine and serotonin, both of which are needed to regulate sleep, mood/emotions, cognition, and learning. Low iron can cause dopamine and serotonin levels to drop.

Iron deficiency can cause the following symptoms:

  • Difficulty paying attention at work
  • Difficulty problem solving
  • Difficulty learning new tasks
  • Brain fog
  • Poor memory
  • Anxiety
  • Depression
  • Difficulty falling or staying asleep
  • Irritability


When to Supplement?

Many doctors may say that someone is “in normal range” until a person becomes anemic. However, research shows that a deficiency in iron can start to cause harm well before hemoglobin drops low enough to be diagnosed as anemic.

 If you suspect you may have low iron levels, based on risk factors or symptoms, a supplement can help.

Having iron levels tested is recommended as a daily maintenance dose of iron will not be enough to correct low levels.

Diet can also help to support and increase iron levels. Read more about iron and food here.

KidStar® BioFe® Iron

KidStar® BioFe® is gentle and will not upset sensitive stomachs or stain teeth like common iron supplements. BioFe+ Iron Liquid is safe for the whole family, from infancy to adulthood.

The iron in BioFe is micronized and microencapsulated, protecting you from the side effects of iron, like constipation, black stools, tummy upset, and grey teeth. Microencapsulation also allows BioFe iron to be taken at the same time as foods and nutrients containing calcium.

Like all KidStar nutrients, our iron supplements do not contain sugar, artificial colours, artificial sweeteners and artificial flavours, soy, gluten and GMOs. KidStar BioFe Iron is available in a tasty liquid, unflavoured liquid drops and a tiny chewable tablet.

Find iron products here


Easy on the stomach, delicious, tiny chewable iron tablet.

BioFe® Pure Iron Tablets


(6 customer reviews)


Iron for the Family Bundle

Iron for the Family Bundle


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Gentle, delicious, iron liquid formula with added vitamins B6 and B12.

BioFe+® Liquid Iron with Vitamin B6 & B12


cartoon image of Rhianna Ross

About the Author

Rhianna Ross, R.H.N., is a registered holistic nutritionist based in Vancouver, BC. Rhianna has more than a decade of experience in the natural health and wellness industry, and currently works at KidStar Nutrients, where she enjoys reviewing and analyzing the latest nutritional research papers, meta-analyses, and journal articles.

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