Teen girls, tired all the time? It could be iron
Fatigue, brain fog, anxious feelings, heavy periods, pale skin, hair loss. For far too many teenage girls, and young women, these are brushed off as hormones, stress, or “just growing up”. A recent Swedish study suggests something quieter may be driving how many teens feel: iron deficiency. It is common, often missed, and more widespread than most people realise.
Out of 475 teenage girls tested, 38% were iron deficient. Among those following vegetarian, vegan or pescatarian diets, the figure rose to nearly 70%. Even in girls who ate meat, around 30% were low in iron.
This matters. Deeply.
Why iron matters so much for teenage girls
The teen years bring rapid growth, physically, mentally and emotionally. Iron supports brain development, concentration, mood, energy, immunity and oxygen transport. During adolescence, iron needs jump.
From 14 to 18 years, the recommended dietary intake (RDI) is 15 mg per day. For girls following vegetarian or vegan patterns, absorption is lower, so a target of 27 mg is often advised. If periods are heavy, which is increasingly common, even that may not be enough. In some cases, the adult RDI of 18 mg (or 32.4 mg for vegetarians and vegans) may be a better fit.
Here is the catch: most teens do not realise they are low in iron until symptoms get loud, or they are mislabelled as something else.
Iron and anxious feelings – a commonly missed connection
One under-recognised sign of low iron is a rise in anxious feelings. This can happen at any age, but it shows up frequently in the teenage years, just as iron needs climb with the onset of menstruation. To be clear, not all anxiety is caused by low iron; these experiences are multifactorial. Still, in both clinic and research, iron deficiency is often untested, undetected and unresolved in teens struggling with anxiousness or low mood. Leave it long enough and a young person may start to believe there is something “wrong” with them, when their body may simply be asking for more iron.
The signs to look for
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Constant fatigue
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Pale skin, especially face or inner eyelids
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Brain fog or poor concentration
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Anxious feelings or low mood
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Frequent sighing
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Heavy menstrual bleeding, or in severe deficiency, missed periods
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Hair thinning or widening part lines
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Shortness of breath with mild activity
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Cold hands and feet
Why food might not be enough
For many teenage girls, especially those experimenting with diet or restricting certain foods, meeting daily iron needs from food alone is tough. Add heavy periods, stress, or a reluctance to eat animal products, and the gap widens. In many cases, a well-chosen iron supplement can make a real difference, not only to physical wellbeing, but to confidence and a sense of self.
A note for parents and caregivers
If you are supporting a teen to improve iron intake, speak to what matters to her. While adults may value health for its own sake, teens are often more motivated by outcomes they can see and feel. Framing iron as a key to stronger, shinier hair, clearer skin, steadier energy for sport and sharper focus for school can help it feel relevant. Again and again, I meet young women who only act when hair starts thinning, then discover a significant iron deficiency behind many of their symptoms.
Iron and menstruation – a two-way street
What is rarely discussed is the loop between iron status and menstrual blood loss. Low iron can contribute to heavier periods. Heavier periods then worsen iron deficiency. If deficiency becomes severe, the body may even pause menstruation to conserve what little iron remains.
The bigger picture
Iron deficiency in the teen years is both common and fixable. I have seen the needless struggle it causes: confusion, exhaustion, misdiagnoses, all preventable with awareness and timely support. If you, or someone you care for, is iron deficient in adolescence, take it seriously.
Address it. Support it. Maintain it, with nourishing food, open conversations and, where needed, a gentle iron supplement. When a teenage girl/ woman has the energy to take part in life, to think clearly, feel connected and trust her own strength, everything shifts. Sometimes, it starts with something as simple as restoring iron.