Hair loss affects millions of people and can occur for many different reasons. While genetics, hormones and stress are well-known contributors, one often overlooked factor is iron deficiency.
Iron plays a vital role in transporting oxygen throughout the body, supporting energy production, immune function and the healthy growth of hair follicles. When iron levels are low, the body may prioritise essential organs over processes such as hair growth, which can contribute to increased hair shedding.
In this article, we'll explore whether iron deficiency can cause hair loss, how iron supports the hair growth cycle, the signs of low iron to look for and practical ways to maintain healthy iron levels.
The Short Answer: Yes, Iron Deficiency Can Contribute to Hair Loss
Iron deficiency is one of the most common nutritional deficiencies worldwide and is recognised as a contributor to diffuse hair shedding, particularly in women.
Hair follicles are among the most metabolically active tissues in the body, meaning they require a constant supply of oxygen and nutrients to support healthy hair growth.
Iron is essential for producing haemoglobin, the protein in red blood cells responsible for transporting oxygen throughout the body, including to the scalp and hair follicles.
When iron stores become depleted, hair follicles may receive less oxygen and fewer nutrients than they need. As a result, more hairs may enter the telogen phase, the resting stage of the hair growth cycle.
This can contribute to telogen effluvium, a form of diffuse hair shedding that often develops several months after a trigger such as iron deficiency, illness, significant stress or hormonal changes.
How Does Iron Deficiency Affect the Hair Growth Cycle?
Hair grows in a continuous cycle consisting of three stages.
1. Anagen Phase (Growth Phase)
This is the active growth stage, during which hair follicles continuously produce new hair. Healthy follicles remain in this phase for several years.
2. Catagen Phase (Transition Phase)
A short transition period where active growth slows and the follicle prepares to enter its resting stage.
3. Telogen Phase (Resting and Shedding Phase)
During this phase, the hair follicle rests before the hair naturally sheds and a new growth cycle begins.
When iron levels are insufficient, hair follicles may move from the anagen phase into the telogen phase earlier than normal.
This may result in:
- Increased hair shedding
- Thinner-looking hair
- Reduced hair density
- Slower hair regrowth
- More noticeable hair loss during brushing or washing
Why Is Iron Important for Hair Growth?
Iron supports healthy hair growth in several important ways.
Oxygen Delivery to Hair Follicles
Iron is required to produce haemoglobin, which transports oxygen throughout the body.
Hair follicles require a continuous supply of oxygen and nutrients to maintain normal growth and renewal.
Cellular Energy Production
Hair follicles are constantly producing new cells, making them highly energy dependent.
Iron contributes to the normal cellular processes involved in energy production, helping support the rapidly dividing cells within the hair follicle.
Keratin Production
Hair is primarily made from keratin, a structural protein that provides strength and resilience.
Adequate nutrition, including sufficient iron intake, helps support the normal processes involved in maintaining healthy hair fibres.
Signs Your Hair Loss May Be Linked to Low Iron
Iron deficiency-related hair loss often looks different from hereditary hair loss.
Possible signs include:
Increased Hair Shedding
You may notice more hair than usual on your pillow, in the shower or on your hairbrush.
Overall Thinning
Rather than causing isolated bald patches, iron deficiency often results in diffuse thinning across the scalp.
Changes in Hair Quality
Hair may become:
- Dry
- Weak
- Brittle
- More prone to breakage
Other Symptoms of Iron Deficiency
Hair loss may occur alongside other symptoms such as:
- Fatigue
- Low energy
- Dizziness
- Feeling cold
- Pale skin
- Reduced exercise tolerance
- Shortness of breath
- Poor concentration
Who Is More at Risk of Iron Deficiency Hair Loss?
Some groups have higher iron requirements or are more likely to develop iron deficiency.
These include:
Women With Heavy Menstrual Periods
Menstruation is one of the most common causes of iron loss in women, particularly when periods are heavy or prolonged.
Pregnancy and the Postpartum Period
Iron requirements increase during pregnancy, while hormonal changes after childbirth can also contribute to increased hair shedding.
Vegetarians and Vegans
Iron from plant foods (non-haem iron) is generally absorbed less efficiently than iron from animal foods, making careful dietary planning important.
Athletes
Regular high-intensity exercise may increase iron requirements through increased red blood cell turnover and iron losses associated with physical activity.
People With Digestive Conditions
Certain gastrointestinal conditions may reduce the body's ability to absorb iron effectively, increasing the risk of deficiency.
Ferritin: Why It Matters for Hair Health
When investigating hair loss that may be related to iron deficiency, healthcare professionals often assess ferritin levels.
Ferritin is a protein that stores iron within the body and provides one of the best indicators of your iron reserves.
Unlike serum iron, which can fluctuate throughout the day, ferritin offers a clearer picture of long-term iron stores.
While reference ranges vary between laboratories, many healthcare professionals consider ferritin an important marker when assessing unexplained hair shedding or symptoms consistent with iron deficiency.
A simple blood test can help determine whether low iron stores may be contributing to your hair concerns.
How to Support Healthy Iron Levels
Maintaining healthy iron levels begins with a balanced diet and identifying any underlying causes of iron deficiency.
Eat Iron-Rich Foods
Including a variety of iron-rich foods in your diet can help support healthy iron stores.
Haem iron (more readily absorbed by the body) is found in:
- Lean red meat
- Poultry
- Seafood
Non-haem iron (found in plant foods) includes:
- Lentils
- Beans
- Spinach
- Tofu
- Fortified breakfast cereals
Because non-haem iron is less readily absorbed, pairing these foods with vitamin C-rich foods such as citrus fruits, berries, kiwi fruit, tomatoes or capsicum can help improve iron absorption.
Iron Supplements and Hair Loss
If blood tests confirm iron deficiency, your healthcare professional may recommend iron supplementation as part of your treatment plan.
Several forms of iron supplements are available, and they differ in their:
- Absorption
- Gastrointestinal tolerance
- Elemental iron content
Common forms include:
- Ferrous sulfate
- Ferrous fumarate
- Ferrous gluconate
- Iron bisglycinate
The most appropriate form of iron supplementation depends on your individual needs, iron status and tolerance. Your doctor or pharmacist can recommend an option based on your circumstances.
It is important not to take iron supplements unless they are recommended by a healthcare professional, as excess iron can also be harmful.
How Long Does It Take for Hair to Improve After Correcting Iron Deficiency?
Hair grows slowly, so improvements are not usually immediate.
Once iron levels have been restored, it may take:
- Several months before hair shedding begins to decrease
- Three to six months, or longer, before noticeable improvements in hair density become apparent
Hair follicles need time to return to their normal growth cycle, so consistency with treatment and follow-up is important.
Other Nutrients That Contribute to Healthy Hair
While iron is an important nutrient for healthy hair growth, it is only one part of the picture.
Healthy hair growth depends on a combination of nutrients working together to support normal hair follicle function.
Protein
Hair is primarily made of keratin, a structural protein.
Consuming adequate dietary protein provides the building blocks needed for healthy hair growth and repair.
Vitamin B12
Vitamin B12 contributes to normal red blood cell formation and energy metabolism, both of which support healthy hair follicles.
Vitamin D
Vitamin D receptors are found within hair follicles, and low vitamin D status has been associated with certain types of hair loss.
Maintaining adequate vitamin D levels supports overall health and normal hair follicle function.
Zinc
Zinc contributes to normal protein synthesis and plays an important role in maintaining healthy hair follicles.
Biotin
Biotin contributes to normal energy metabolism and plays a role in maintaining healthy hair.
The Bottom Line
Iron deficiency is one of the most common nutritional deficiencies worldwide and is a recognised contributor to diffuse hair shedding, particularly in women.
Because hair follicles are highly metabolically active, they rely on a constant supply of oxygen and nutrients to support healthy growth. When iron stores become depleted, the normal hair growth cycle may be disrupted, contributing to increased hair shedding.
If you're experiencing unexplained hair loss, speaking with your healthcare professional about checking your iron status, including ferritin levels, may help identify whether iron deficiency is a contributing factor.
Healthy hair relies on many factors, including adequate nutrition, healthy iron stores and overall wellbeing. Supporting these foundations is an important part of maintaining normal hair growth over time.
References
- Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatology and Therapy. 2019;9:51-70.
- Trost LB, Bergfeld WF, Calogeras E. The Diagnosis and Treatment of Iron Deficiency and Its Potential Relationship to Hair Loss. Journal of the American Academy of Dermatology. 2006;54(5):824-844.
- Rushton DH, Norris MJ, Dover R, Busuttil N. Causes of Hair Loss and the Developments in Hair Re-growth. International Journal of Cosmetic Science. 2002;24(1):17-23.
- National Institutes of Health Office of Dietary Supplements. Iron Fact Sheet for Health Professionals.
- National Institutes of Health Office of Dietary Supplements. Vitamin B12 Fact Sheet for Health Professionals.
- National Institutes of Health Office of Dietary Supplements. Vitamin D Fact Sheet for Health Professionals.
- National Institutes of Health Office of Dietary Supplements. Zinc Fact Sheet for Health Professionals.
