Low iron shows up across your body in ways you might not expect. Beyond the fatigue most people associate with it, iron deficiency leaves visible clues on your skin, nails, hair, tongue, and even your behavior. Some signs are subtle enough to miss for months. Others are hard to ignore once you know what to look for.
Pale Skin, Lips, and Eyelids
The most recognizable sign of low iron is pallor, a washed-out appearance that goes beyond your natural complexion. Iron is essential for making hemoglobin, the protein in red blood cells that gives blood its red color. When hemoglobin drops, less oxygenated blood reaches your skin’s surface, and the result is visible.
Pallor can show up on your face, but it’s easier to spot in specific places: the inside of your lower eyelids, your nail beds, your palms, and the inside of your lips. If you pull your lower eyelid down in front of a mirror, the inner lining should look vibrant red. A very pale pink or yellowish color suggests your iron may be low. In people with darker skin tones, the inner eyelid is often the only reliable place to detect this change visually.
No single spot on the body is a perfect screening tool on its own. Checking the eyelids alone catches moderate and severe anemia fairly well but can miss milder cases. However, looking at several areas together (eyelids, palms, nail beds, and inside the mouth) significantly improves accuracy. The palms are particularly useful because the skin there is thick, translucent, and has very little melanin, making changes in blood flow easier to see. In anemia, the creases of the palms lose their normal reddish tint and appear pale.
Changes to Your Nails
Your fingernails can be an early warning system. In iron deficiency, reduced blood flow to the nail bed causes a whitish discoloration underneath the nail. Over time, the nails themselves may become brittle, dry, and crack easily.
The most distinctive nail change is called koilonychia, or spoon nails. It usually starts with nails flattening out, losing their normal slight curve. Eventually, the center of the nail develops an indentation deep enough to hold a drop of water, giving it a spoon-like shape. The nails also feel softer than usual. Spoon nails are one of the more specific physical signs of iron deficiency anemia, meaning if you see them, low iron is a leading suspect.
A Smooth, Sore Tongue
Iron plays a direct role in maintaining the health of your oral tissues. When levels drop low enough, the tiny bumps on your tongue (papillae) start to flatten and disappear. Once roughly half of these bumps are gone, the tongue takes on a noticeably smooth, glossy appearance against a red or pink background. This condition, called atrophic glossitis, often comes with pain, burning, and a noticeable loss of taste.
The mechanism is straightforward: low hemoglobin means less oxygen delivered to the tongue’s surface, which leads to tissue thinning and breakdown. Iron deficiency also weakens the lining of the mouth more broadly, disrupting the normal balance of bacteria and reducing blood flow to the tissue.
Cracking at the corners of the mouth is another oral sign. These painful splits, which can crust over and reopen when you eat or talk, are more likely to develop when iron, vitamin B12, or folate levels are low. If you’re getting persistent cracks at the corners of your lips that don’t respond to lip balm, low iron is worth investigating.
Hair Thinning and Shedding
Iron deficiency is one of the most common nutritional causes of hair loss in women. The pattern is diffuse, meaning hair thins evenly across the entire scalp rather than receding at the hairline or forming bald patches. You might notice more hair on your pillow, in the shower drain, or coming out when you brush.
Hair follicles are among the fastest-dividing cells in your body and need a steady supply of iron to function. When iron stores (measured by a blood protein called ferritin) drop below about 20 ng/mL, follicles shift prematurely from their growth phase into a resting and shedding phase. In one study of premenopausal women with this type of hair loss, 62.5% had ferritin levels below that threshold, compared with 30% of women without hair problems. Under magnification, affected scalps show decreased hair density everywhere, with individual follicles producing only one hair shaft instead of the usual cluster, and noticeable variation in hair thickness.
Compulsive Ice Chewing and Other Cravings
One of the stranger signs of low iron is an intense, persistent craving for ice. This isn’t a preference for cold drinks. It’s a compulsion to chew through cups of ice cubes daily, sometimes for hours. Up to half of people with iron deficiency anemia develop some form of pica (craving non-nutritive substances), and ice chewing is by far the most common type, accounting for roughly 87% of pica cases in iron-deficient patients.
The leading theory is that chewing ice triggers a reflex that constricts blood vessels in the extremities and redirects blood flow to the brain. For someone whose blood is carrying less oxygen than normal, this temporary boost in brain perfusion improves alertness and mental processing speed. Research has confirmed that chewing ice actually does improve cognitive performance in anemic individuals but has no effect in people with normal iron levels. In other words, the craving may be the body’s attempt to compensate for the mental fog that iron deficiency causes. Other explanations include ice’s ability to soothe the tongue pain and inflammation that often accompany anemia.
Restless Legs at Night
If your legs feel uncomfortable, tingly, or like they need to move when you’re lying down at night, low iron may be the cause. Iron is involved in producing dopamine, a brain chemical that helps regulate movement. When iron stores are depleted, dopamine signaling in the brain is disrupted, creating those restless, creeping sensations that only movement temporarily relieves.
The connection is well established enough that clinicians look at ferritin levels in anyone with restless legs. Symptoms can occur even when ferritin is technically in the “normal” range. Current guidelines consider levels at or below 75 ng/mL worth addressing in someone with restless legs, which is well above the general threshold for diagnosing iron deficiency (around 15 to 25 ng/mL depending on the guideline). This means your iron stores can be low enough to cause restless legs long before they’re low enough to show up as anemia on a standard blood test.
How Iron Deficiency Is Measured
If you recognize several of these signs, a simple blood test can confirm whether iron is the cause. The most useful marker is serum ferritin, which reflects how much iron your body has in storage. The World Health Organization defines iron deficiency as ferritin below 15 μg/L for women and below 12 μg/L for children under five. The U.S. CDC uses a cutoff of 15 μg/L for anyone over six months old.
However, a large 2025 multinational study found that hemoglobin levels actually start declining once ferritin drops below about 25 μg/L in women and 22 μg/L in children, suggesting the traditional cutoffs may miss early-stage deficiency. This helps explain why many people experience symptoms like fatigue, hair loss, and restless legs with ferritin levels that technically fall within the “normal” range on a lab report.
Iron deficiency exists on a spectrum. In the earliest stage, your stored iron drops but your blood counts look normal and you may feel fine. As stores deplete further, symptoms like hair thinning, brittle nails, and fatigue appear. Full iron deficiency anemia, where hemoglobin itself drops, is the most advanced stage and produces the most visible signs: marked pallor, spoon nails, a smooth tongue, and significant fatigue with even light activity.