Iron deficiency in teenagers (14–18): causes, symptoms, and treatment options

Iron deficiency is one of the most common nutritional deficiencies in teenagers. In many cases, it is mistaken for everyday tiredness, stress, or the demands of school life. However, low iron levels can have a significant impact on energy, concentration, mood, and physical performance — all of which are especially important during adolescence.

Recognising the signs early and understanding the underlying causes is key to effective treatment and long-term wellbeing.

Why Iron Matters in Adolescence

Teenage years are a period of rapid growth and increased physiological demand. Iron plays a vital role in producing haemoglobin, which carries oxygen around the body. When iron levels are low, the body struggles to meet its oxygen demands, leading to symptoms that can affect both physical and cognitive function.

Common Symptoms of Iron Deficiency in Teenagers

Iron deficiency in teenagers can present in subtle ways and is often overlooked. Common symptoms include:

• Persistent fatigue or low energy
• Headaches or dizziness
• Reduced exercise tolerance or rapid tiring during sport
• Difficulty concentrating or “brain fog”
• Shortness of breath on exertion
• Pale skin or noticeable pallor
• Cravings for non-food substances such as ice (known as pica)

These symptoms can easily be attributed to busy school schedules or lifestyle factors, which is why blood testing is important when iron deficiency is suspected.

Common Causes of Iron Deficiency in Teenagers

There are several reasons why iron deficiency develops in this age group:

Rapid growth and increased demand

During adolescence, the body requires more iron to support growth, increased blood volume, and hormonal changes.

Dietary insufficiency

Teenagers may have low dietary iron intake due to:

• Restricted diets
• Low consumption of iron-rich foods (such as red meat, legumes, or leafy greens)
• Busy or irregular eating patterns

Heavy menstrual bleeding

In teenage girls, heavy or prolonged periods are a very common cause of iron loss and should always be considered.

Gastrointestinal conditions

Less commonly, underlying conditions may affect iron absorption or cause chronic loss, including:

• Coeliac disease
• Inflammatory bowel disease (IBD)
• Reduced absorption (rare in this age group)

Previous gastrointestinal surgery or underlying malabsorption disorders can also contribute, although this is less common in teenagers.

How Iron Deficiency is Diagnosed

Diagnosis cannot be made based on symptoms alone — blood testing is essential.

Typical investigations include:

• Full Blood Count (FBC) – to assess haemoglobin and red blood cell indices
• Ferritin – the most important marker of iron stores
• Iron studies (including TSAT) – to assess circulating iron availability
• CRP (C-reactive protein) – to help interpret ferritin when inflammation may be present

Interpreting these results together provides a clearer picture of iron status and whether true deficiency is present.

Treatment Options: Oral Iron vs IV Iron

Oral iron (first-line treatment)

Oral iron supplements are usually the first step. They are effective for many teenagers, but may cause side effects such as:

• Nausea
• Constipation
• Abdominal discomfort
• Poor adherence due to taste or tolerability

Intravenous (IV) iron

IV iron may be considered when:

• Oral iron is not tolerated
• Oral iron has not been effective
• There is a need for rapid improvement (e.g., significant symptoms or upcoming exams/sport commitments)
• Absorption issues are suspected

IV iron can restore iron stores more quickly and reliably in selected cases.

Our Specialist Pathway for 14–18-Year-Olds

At The Health Suite, we offer a structured and specialist-led approach to iron deficiency in teenagers.

Our young people’s IV iron pathway is led by a paediatric gastroenterologist, ensuring a high level of clinical expertise and safety.

This pathway includes:

• Careful assessment before treatment
• Safe prescribing and dosing
• Appropriate monitoring during and after infusion
• Attention to important considerations, such as phosphate levels when using preparations like Ferinject
• Evaluation of potential underlying causes was indicated

Our aim is not only to correct iron deficiency but also to ensure that any contributing medical issues are properly investigated and managed.

A Balanced Approach to Teenage Iron Deficiency

Iron deficiency in teenagers should never be dismissed as simple tiredness. With the right investigation and treatment, most young people experience a significant improvement in energy, focus, and overall well-being.

Early recognition, appropriate testing, and tailored treatment can make a meaningful difference during a crucial stage of development.