Quick Answer
There is no definitive amount of iron that will guarantee hair regrowth. However, getting enough iron is important for healthy hair growth. Iron deficiency can lead to hair loss, so ensuring adequate iron intake through diet or supplements may help promote regrowth in those with iron deficiency. Speak to your doctor about testing your ferritin levels.
Iron and Hair Loss
Iron is an essential mineral that has many important functions in the body. One of its roles is to help carry oxygen throughout the body in the protein hemoglobin. Iron is also needed for the activity of iron-containing enzymes that help with vital processes like DNA synthesis and collagen production.
Collagen is the most abundant protein in the body and makes up much of the structure in skin, nails, and hair. Without adequate iron levels, your body can’t properly synthesize collagen. This can lead to problems with skin, nail, and hair health.
Iron deficiency is one of the most common nutritional deficiencies worldwide. It is estimated that up to 20% of women of childbearing age have iron deficiency. The signs and symptoms of iron deficiency include:
Signs and Symptoms of Iron Deficiency
- Fatigue and weakness
- Pale skin
- Shortness of breath
- Dizziness or lightheadedness
- Headaches
- Inflammation or soreness of the tongue
- Brittle nails
- Hair loss
Hair loss and thinning associated with iron deficiency often occurs because the hair follicles are not receiving adequate nutrition for normal growth. Over time, this leads to decreased hair density and shedding. Typically the hair loss is diffuse, meaning it occurs all over the scalp.
Some research indicates iron deficiency may disrupt the hair cycle. The normal cycle of hair growth consists of a long growing phase (anagen), a brief transition phase (catagen) and a short resting phase (telogen). In iron deficiency, the anagen phase is shortened and more hair shifts into the resting phase, resulting in shedding and hair loss.
Treating the underlying iron deficiency is key to stopping hair loss related to low iron levels. With proper iron replenishment, the hair follicles can recover and normal hair cycling can resume.
Assessing Iron Status
Since iron deficiency is often behind hair loss, getting an assessment of your iron levels is recommended. There are several lab tests that can be used:
Serum Iron
A serum iron blood test measures the amount of circulating iron bound to transferrin, a protein that transports iron in the bloodstream. Values below 50 μg/dL are considered low. However, serum iron can vary throughout the day so this test may not always reflect iron stores accurately.
Ferritin
Ferritin is the storage form of iron in the body. A serum ferritin test is the best way to assess iron levels. Ferritin below 15 ng/mL indicates iron depletion. Ferritin between 15-30 ng/mL is consistent with iron deficiency. Levels less than 12 ng/mL are strongly associated with diffuse hair loss. Optimally, ferritin should be between 40-70 ng/mL for healthy hair.
Total Iron Binding Capacity (TIBC)
TIBC measures the blood’s capacity to bind iron. High TIBC indicates low iron levels. People with iron deficiency usually have a TIBC above 400 μg/dL.
Transferrin Saturation
Transferrin saturation shows the amount of iron bound to transferrin compared to how much it could potentially bind. Transferrin saturation below 15% indicates iron deficiency.
Complete Blood Count
A complete blood count (CBC) can detect anemia, a common consequence of iron deficiency. Low levels of hemoglobin and hematocrit on a CBC provide evidence of anemia.
Checking serum ferritin is the preferred method for identifying iron deficiency. When iron deficiency is found, further evaluation may help determine the cause.
Causes of Iron Deficiency
Some potential causes for low iron levels include:
- Inadequate dietary intake – An iron-poor diet can gradually deplete iron over time.
- Blood loss – Losing blood from heavy menstruation, frequent blood donations, ulcers, hemorrhoids, or other sources.
- Pregnancy and breastfeeding – Increased iron demands can lead to deficiency.
- Malabsorption – Conditions like celiac disease and inflammatory bowel disease impair intestinal absorption of iron.
- Helicobacter pylori infection – This stomach bacterium can cause bleeding and reduce iron absorption.
Identifying and addressing any sources of blood loss or conditions contributing to poor iron absorption are necessary to correct iron deficiency.
Iron Requirements
The recommended dietary allowance (RDA) for iron intake is:
- 8 mg/day for adult men and postmenopausal women
- 18 mg/day for premenopausal women
- 27 mg/day for pregnant women
However, the optimal amount of iron needed for regrowing hair can vary on an individual basis. It depends on the severity of iron deficiency, cause of hair loss, presence of other deficiencies or underlying conditions, and other factors.
Some sources suggest that iron intake between 40-80 mg/day may promote hair growth in those with chronic hair loss or thinning related to iron deficiency. However, amounts in this upper range should only be taken with medical supervision.
Too much iron can be harmful and cause side effects like abdominal discomfort, constipation, nausea, and vomiting. The tolerable upper limit (TUL) for iron is 45 mg/day for adults.
Dietary Iron Sources
Dietary iron occurs in two forms:
- Heme iron – Found in animal products such as red meat, poultry, and seafood. Heme iron is readily absorbed.
- Non-heme iron – Found in plant foods like beans, lentils, spinach, nuts, seeds, and iron-fortified grains. Non-heme iron has lower bioavailability.
Including both plant and animal sources of iron can help maximize absorption. Vitamin C also enhances iron absorption, so pairing iron-rich foods with vitamin C sources like citrus, peppers, broccoli and strawberries is beneficial.
Some good dietary sources of iron include:
| Food | Iron Content |
|---|---|
| Oysters | 7.2 mg per 3 oz |
| Dark chocolate | 7 mg per 1 oz |
| Beef liver | 5.8 mg per 3 oz |
| Lentils | 3.3 mg per 1/2 cup |
| Spinach | 3.2 mg per 1/2 cup |
| Beef | 2.7 mg per 3 oz |
Iron Supplements
If diet alone cannot restore iron levels, iron supplementation may be recommended. Iron supplements are available in different forms:
- Ferrous sulfate – Most commonly prescribed iron supplement. Ferrous sulfate contains 33% elemental iron.
- Ferrous fumarate – Contains 33% elemental iron.
- Ferrous gluconate – Has lower elemental iron (12%) but may be easier on the stomach.
- Iron polysaccharide complex – Made up of ferric iron bound to a polysaccharide. Considered gentle on the stomach.
- Heme iron polypeptide – Uses heme iron derived from animal blood. Heme iron is better absorbed.
The amount of elemental iron provided by supplements is more important than the dose. For example, 325 mg of ferrous sulfate contains about 105 mg of actual iron.
Supplemental iron is available in regular or extended release formulations. Extended release iron may cause less gastrointestinal side effects. Taking iron with food can also minimize upset stomach. Vitamin C aids absorption but should be taken at a different time than the iron if it causes nausea.
Iron supplementation can replenish stores and normalize ferritin levels in a few months. Hair regrowth may take longer since follicles need time to recover from damage. Most clinicians recommend continuing iron supplements for 6 months after ferritin normalizes before rechecking levels.
Oral iron has limitations. Absorption decreases rapidly with increasing doses above 45 mg of elemental iron per day. Intravenous iron infusion can be considered for severe deficiency when supplements are not tolerated or ineffective.
Other Nutrients for Healthy Hair
While iron is critical, getting adequate amounts of other hair-friendly nutrients can also help optimize hair growth and thickness.
Zinc
Zinc deficiency is commonly seen along with iron deficiency. Zinc is crucial for protein synthesis, DNA production, and cell division which are all needed for hair follicle growth. The RDA for zinc is 8 mg daily for women and 11 mg for men. Foods high in zinc include oysters, meat, nuts, seeds, and legumes.
Protein
Adequate protein intake is vital for hair health, providing the amino acids required to construct hair proteins. Insufficient protein has been linked to hair loss. Getting at least 0.5 grams of protein per pound of body weight is recommended. Lean meats, fish, eggs, beans and nuts are good protein sources.
Biotin
Biotin, also called vitamin B7, helps produce keratin which forms the structure of hair. While biotin deficiency is rare, supplements providing 30-100 mcg per day may promote faster, thicker hair growth.
Vitamin D
Research indicates vitamin D may stimulate hair follicles and trigger the anagen growth phase. Vitamin D can be obtained through sun exposure, fatty fish, eggs, and fortified foods. Vitamin D3 supplements may also be beneficial.
Vitamin C
Vitamin C aids iron absorption and is essential for collagen production. Vitamin C also has antioxidant properties that help protect hair follicles from damage. Citrus fruits, peppers, strawberries and broccoli are good sources of vitamin C.
Other Remedies for Hair Regrowth
Beyond nutrition, some other remedies thought to stimulate hair growth include:
Scalp massage
Gentle massage may increase circulation to hair follicles and promote growth. Using oil or serum enriched with essential oils like rosemary, peppermint, and lavender could enhance effects.
Laser devices
Low-level laser light devices have tentative evidence for stimulating hair growth. These combs, caps and headbands use cool laser light on the scalp. More data is still needed on effectiveness.
Minoxidil
Minoxidil is an over-the-counter topical solution for regrowing hair. It works by widening blood vessels, allowing better delivery of nutrients and oxygen to follicles. Minoxidil must be used continually to maintain benefits.
Prescription medications
Medications like finasteride and spironolactone can treat hormonal causes of hair loss like androgenetic alopecia. These require a prescription and close medical monitoring.
PRP injections
Platelet-rich plasma (PRP) therapy involves reinjecting concentrated plasma from your own blood into the scalp. PRP provides growth factors that may stimulate follicles. Multiple treatments are usually needed.
More clinical evidence is required to confirm efficacy of these alternative approaches. Discuss any new treatments with your doctor, especially if taking medications or managing a health condition.
Conclusion
Iron deficiency is a common cause of hair loss in women and men. Getting tested to check ferritin and iron levels can determine if low iron is contributing to hair thinning. Addressing any sources of blood loss and including iron-rich foods or supplements can help restore iron status.
While iron is critical, optimal hair growth depends on getting enough of other key nutrients like zinc, protein, biotin and vitamins C and D. Choose a balanced diet or supplements to provide the necessary nutritional support for strong, healthy hair. Other remedies like scalp massage, laser devices and growth stimulant medications may provide added benefit when iron levels are replete.
With a comprehensive approach, the hair damage caused by iron deficiency can be reversed. New hair growth may occur progressively over a period of months. Patience and consistency with nutritional support and treatments are key to maximizing hair regrowth potential.