What blood tests check why I’m always cold?

MedlinePlus lists a complete blood count, a comprehensive metabolic panel, TSH and thyroid hormone levels (T3, T4). A clinician may add ferritin if the blood count suggests low iron, and HbA1c if diabetes is possible.

Can low iron make you feel cold?

Yes. The American Society of Hematology lists cold intolerance among the symptoms of iron-deficiency anemia, along with tiredness, pale skin and shortness of breath. A clinician decides on iron after a test and looks for the reason the iron is low, such as heavy periods or bleeding in the gut.

Can thyroid problems make you cold?

Yes. An underactive thyroid commonly causes fatigue, weight gain and trouble tolerating cold. A high TSH most often means the thyroid is underactive, and TSH is usually the first test.

Is being always cold a sign of diabetes?

Not directly. Diabetes raises the risk of peripheral artery disease, where one foot may feel colder than the other, and of nerve damage, which affects how well you sense temperature in the feet and hands. Up to one-half of people with diabetes have peripheral neuropathy.

When is feeling cold an emergency?

The CDC calls hypothermia a medical emergency: watch for shivering, exhaustion, confusion, fumbling hands, memory loss, slurred speech or drowsiness, and get medical attention immediately if body temperature is below 95°F. A limb that suddenly turns cold, pale and painful can be a blocked artery and also needs emergency care: call 911.

Why are women always cold?

Primary Raynaud’s, the most common form, is more common in women and usually starts before age 30. Women are also much more likely than men to have an underactive thyroid, and heavy periods are a common cause of iron deficiency.

Why am I always cold? The common causes of feeling cold

Q: Why am I always cold?

MedlinePlus lists anemia, anorexia nervosa, blood vessel problems such as Raynaud’s phenomenon, an underactive thyroid, chronic severe illness and, rarely, a problem with the hypothalamus (the brain’s thermostat) as causes of cold intolerance. Day to day, cold and stress narrowing the skin’s blood vessels, smoking, some medicines and eating too little also leave people colder than those around them.

Q: Why are my hands and feet always cold?

Cold and stress narrow the small blood vessels in the skin, and in Raynaud’s phenomenon that narrowing is quicker and lasts longer. Medicines for high blood pressure, migraines or ADHD can cause or worsen it, and beta blockers such as propranolol list cold fingers or toes as a common side effect. One foot colder than the other, leg pain when walking or sores that heal slowly can point to peripheral artery disease.

The distinctions

01
Cold all over and cold hands and feet point to different causes
Feeling cold all over when others are comfortable (cold intolerance) points first to the whole body: an underactive thyroid, anemia, or too little body fat or food. Cold hands and feet with a warm body point first to the blood vessels in the skin: cold, stress, smoking, a medicine, Raynaud’s or narrowed arteries. Saying which one you have sends the search the right way.
02
Colour change matters more than coldness
Cool fingers on a winter day are the body keeping its core warm. Fingers or toes that turn white, then blue, then red, a sore on a fingertip, or one foot colder than the other are the signs worth showing a clinician.

If you are always cold when others are comfortable, the medical causes clinicians check first are an underactive thyroid, anemia (too few healthy red blood cells, often from low iron) and being underweight or eating too little; MedlinePlus calls this cold intolerance. ¹ If it is mostly your hands and feet, the usual reasons are blood vessels in the skin narrowing with cold or stress, Raynaud’s phenomenon (fingers or toes that turn white or blue in the cold), a medicine such as a beta blocker, or narrowed leg arteries. ⁶⁹¹¹ A complete blood count and a TSH thyroid test check the commonest medical causes. ¹

When to get help now

Most people who feel cold are not in danger. These signs are the exceptions.

Call 911 or your local emergency number

Shivering with confusion, slurred speech, fumbling hands, memory loss or drowsiness ⁸
A body temperature below 95°F ⁸
An arm or leg that suddenly turns cold, pale, numb and painful, or weak and hard to move ¹⁸

See a doctor soon, the same day if you can

A finger or toe that stays white or blue after warming, turns black, or has a sore or broken skin ¹⁹
Sores on the toes, feet or legs that heal slowly or not at all, or one foot colder than the other ⁹
Color changes on only one side of the body, or starting for the first time after age 30 ⁷
Cold fingers with joint pain, skin rashes or muscle weakness ⁷
Weight loss, eating very little, or feeling cold, dizzy or very tired with it ¹³
Feeling cold for weeks with tiredness, weight gain, constipation or low mood ¹⁴

LifeFrom can't examine you or assess a symptom. If something feels seriously wrong, trust that and get care rather than waiting on a test.

Cold all over, or cold hands and feet?

MedlinePlus defines cold intolerance as “an abnormal sensitivity to a cold environment or cold temperatures.” ¹ That is different from cold hands and feet in a body that otherwise feels fine. When you are cold or stressed, the small blood vessels near the skin “constrict (narrow),” which keeps warmth in the core and leaves fingers and toes cool. ⁶ Everyone does this. In Raynaud’s phenomenon the narrowing comes on faster and lasts longer, and the skin goes pale, then blue, then red as blood returns. ⁶

What you notice	Points first to	What checks it
Cold all over, needing a sweater when others don’t	Underactive thyroid, anemia, low body weight or eating too little ¹	Blood count, TSH, thyroid hormones, metabolic panel ¹
Fingers or toes that go white, blue, then red in the cold or with stress	Raynaud’s phenomenon ⁶	Examination; nailfold capillaroscopy (a magnified look at the nail-bed vessels) ⁶
Cold hands and feet that stay pink, no color change	Cold room, stress, smoking, caffeine, a medicine ¹¹	Your own notes; a medicine review
One foot colder than the other, leg pain when walking	Peripheral artery disease (narrowed leg arteries) ⁹	A clinician’s exam and pulse checks; blood sugar if diabetes is possible

What can cause it, most likely first

Ranked from most to least likely in adults in general. The order shifts with age, sex and history: Raynaud’s and low iron move up for younger women, an underactive thyroid for women in midlife, and narrowed arteries for older adults who smoke or have diabetes.

01
Cold, stress and narrowing skin blood vesselsEverydaycommon
Cold and emotional stress both make the small blood vessels in the skin narrow, so hands and feet cool first. ⁶ The NHS notes that fingers and toes can change color “When you're cold, anxious or stressed.” ⁷ If your hands warm up quickly indoors and stay their normal color, this everyday response is the likeliest reason.
02
Smoking, caffeine and some medicinesEverydaycommon
Smoking and caffeine narrow blood vessels, and beta blockers such as propranolol list cold fingers or toes as a common side effect. ¹¹ Medicines for high blood pressure, migraines or attention-deficit/hyperactivity disorder (ADHD) can bring on or worsen Raynaud’s-type symptoms. ⁶ Cigarette smoking and vaping can trigger attacks too. ⁶ Do not stop a medicine on your own; ask the prescriber whether it could be the cause.
03
Raynaud’s phenomenonMedicalcommon
In Raynaud’s, fingers or toes turn white, then blue, then red with cold or stress, and attacks can last minutes or hours. ⁶ The primary form has no known cause, is more common in women and usually starts before age 30; the secondary form sits alongside a condition such as lupus or scleroderma and tends to be more serious. ⁶ There is no routine blood test for it; a clinician tells the two apart, “most commonly” with nailfold capillaroscopy, and may arrange tests if another condition is suspected. ⁶⁷
04
Being underweight or eating too littleEverydayless common
Anorexia nervosa is on the MedlinePlus list of causes of cold intolerance, and the NHS lists “feeling cold, dizzy or very tired” and “poor circulation in hands and feet” among its symptoms. ¹¹³ If restricting food is part of the picture, a clinician can help, and it is worth raising early. ¹³
05
Underactive thyroidMedicalless common
Hypothyroidism (an underactive thyroid) commonly brings fatigue, weight gain and trouble tolerating cold. ² Nearly 5 out of 100 Americans ages 12 and older have it, most mildly, and women are much more likely to. ² Other early signs are feeling slowed down, constipation and low mood. ¹⁴
Can be linked with Hypothyroidism
TSH
A high TSH (thyroid stimulating hormone) most often means an underactive thyroid; TSH is usually the first thyroid test. ³
Free T4
A low T4 with a high TSH fits an underactive thyroid. ³ See how to read your thyroid panel.
06
Anemia and low ironMedicalless common
Anemia is on the MedlinePlus list of causes of cold intolerance, and the American Society of Hematology lists cold intolerance among the symptoms of iron-deficiency anemia, with tiredness, pale skin and breathlessness. ¹⁴ Heavy periods are a common cause in women before menopause, and bleeding in the stomach or gut accounts for a share of cases. ⁵ A clinician decides on iron after a test and looks for the cause.
Can be linked with Anemia
Hemoglobin
Low hemoglobin means anemia; the rest of the blood count and ferritin help show why. See the CBC explainer.
Ferritin
Low ferritin points to low iron stores; under 15 ng/mL fits iron deficiency, and a 30 ng/mL cutoff catches far more cases. Inflammation can push ferritin up and hide a deficiency. ⁵ See iron deficiency.
Vitamin B12
A low B12 is another cause of anemia, and a low or low-normal result with symptoms is followed by a methylmalonic acid test. ¹⁶ See B12 deficiency.
07
Narrowed leg arteries and diabetesMedicalless common
In peripheral artery disease (PAD), narrowed arteries cut blood flow to the legs: “One foot may feel colder than the other,” the foot may look pale or blue, and walking can bring leg pain that eases with rest. ⁹ Smoking, diabetes and older age raise the risk. ¹⁰ Diabetes can also damage nerves, which makes it harder to sense temperature in the feet and hands. ¹²
Can be linked with Prediabetes
HbA1c
A high HbA1c (6.5% or above) points to diabetes, and 5.7% to 6.4% to prediabetes. ¹⁵ Diabetes raises the risk of narrowed leg arteries and nerve damage. ¹⁰¹² See blood sugar explained.
08
Long-term illness or a hypothalamus problemMedicalrare
Chronic severe illness, general poor health and, rarely, a problem with the hypothalamus (the part of the brain that sets body temperature) are also on the MedlinePlus list. ¹ These usually bring other symptoms that lead the search, and a comprehensive metabolic panel, which reads kidney and liver function and blood salts, is one of the listed tests. ¹
eGFR
Part of the metabolic panel; a low eGFR points to reduced kidney function. See kidney function explained.

These are things a symptom like this can be linked with, not a diagnosis. Several can sit together, and a clinician who knows your history puts them in order for you.

Why are my hands and feet always cold?

Cold hands and feet with a warm body are mostly about the skin’s blood supply. Cold and stress narrow the vessels, smoking and caffeine narrow them further, and a beta blocker can add to it. ⁶¹¹ Raynaud’s is the next step up: the NHS calls it “common,” says it “does not usually cause severe problems,” and lists pain, numbness and pins and needles alongside the color change. ⁷ What changes the picture is a pattern that does not fit: color change on only one side, first symptoms after age 30, or Raynaud’s with joint pain, rashes or muscle weakness, which are reasons to see a GP. ⁷ Numbness and tingling without color change are covered on tingling hands and feet.

Why am I always cold and tired?

Feeling cold and tired together is the pairing that most often leads to a blood test, because the two causes that produce both are an underactive thyroid and anemia. ²⁴ MedlinePlus lists “Fatigue or feeling slowed down,” constipation, weight gain and low mood among the early signs of an underactive thyroid. ¹⁴ Iron-deficiency anemia brings tiredness, breathlessness with effort, a fast heartbeat and cold intolerance. ⁴ Eating too little does the same, with dizziness. ¹³ For the wider list of reasons people feel drained, see fatigue.

Why am I cold when it’s warm?

Feeling chilled in a warm room, with no fever, is the core meaning of cold intolerance, and MedlinePlus advises contacting your provider “if you have long-term or extreme intolerance to cold.” ¹ Feeling cold with a fever and shivering is a different thing: that is the body raising its temperature to fight an infection. Feeling suddenly cold after being out in the cold, with confusion or drowsiness, is hypothermia, and the CDC calls it “a medical emergency.” ⁸

If a person's temperature is below 95 degrees get medical attention immediately.

Centers for Disease Control and Prevention, Preventing hypothermia ⁸

What tests check why you’re always cold?

The tests MedlinePlus lists for cold intolerance are short: a complete blood count, a comprehensive metabolic panel, a serum TSH and thyroid hormone levels (T3 and T4). ¹ Ferritin is added when the blood count or history suggests low iron. ⁵ Raynaud’s and narrowed arteries are found by examination: a look at the nail-bed vessels for Raynaud’s, and pulse checks for the legs. ⁶⁹

Test	What it looks for	When it is added
Complete blood count	Anemia	First round ¹
TSH, then free T4 or T3	Underactive thyroid	First round ¹³
Comprehensive metabolic panel	Kidney and liver function, blood salts, glucose	First round ¹
Ferritin	Low iron stores	When the blood count or heavy periods suggest low iron ⁵
HbA1c	Diabetes	When narrowed arteries or nerve damage are possible ¹⁰¹²
Nailfold capillaroscopy	Primary or secondary Raynaud’s	Color change in the fingers or toes ⁶

The panel that checks these

If a clinician tests, a complete blood count and TSH come first, because together they check anemia and an underactive thyroid, the two commonest medical causes of feeling cold. ¹ None of these needs fasting except a fasting glucose. Ferritin is best read alongside CRP, because inflammation raises ferritin. ⁵

TSHUnderactive thyroid
Free T4Underactive thyroid
HemoglobinAnemia and low iron
FerritinAnemia and low iron
Vitamin B12Anemia and low iron
HbA1cNarrowed leg arteries and diabetes
eGFRLong-term illness or a hypothalamus problem

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Getting a useful test

Say whether you are cold all over or in your hands and feet, and whether your fingers or toes change color. ¹⁶
Take a photo of your fingers or toes during an attack; color change can be gone by the time you are seen.
List every medicine with its start date, including blood pressure, migraine and ADHD medicines. ⁶
Mention smoking or vaping, caffeine, heavy periods, recent weight loss and how much you are eating. ⁵⁶¹³
Mention high-dose biotin (in many hair and nail products), which can make TSH look falsely low; the American Thyroid Association advises a gap of at least 2 days before thyroid testing, a step to agree with your clinician. ¹⁷
One result is a snapshot; see why trends beat single readings.

What may help

Most people who feel cold find relief in the everyday steps. None replaces checking the red flags above.

Start with the everyday things

Keep your home warm and dress in layers, with hands and feet covered; mittens keep fingers warmer than gloves. ⁷¹¹
Warm cold hands or feet under warm running water, massage them and wiggle your fingers and toes. ¹¹
Avoid tight watches or bracelets, and avoid sudden temperature changes. ⁷¹¹
Stopping smoking and limiting caffeine helps, since both narrow blood vessels. ⁷¹¹
Regular exercise and relaxation, such as breathing exercises or yoga, can ease Raynaud’s attacks. ⁷

No supplement is listed here: none has good evidence for feeling cold, and the medical causes worth finding (thyroid, anemia, narrowed arteries) need a clinician. Iron in particular is for a clinician to decide after a test. Supplements support general wellness. They don't treat the causes above, and if a test finds one, treating that comes first. If you take medicines, are pregnant or have a health condition, check with your clinician before starting anything.

Questions to ask your clinician

Do my symptoms sound like cold intolerance or like Raynaud’s?
Should I have a blood count, ferritin and TSH?
Could any of my medicines be making my hands and feet cold?
Do the pulses in my feet feel normal?
Which signs would mean I should come back sooner?

This page is general education, not medical advice or a diagnosis. Feeling cold has many causes that can overlap, and the clinician who knows your history and examines you is the one to read your results and put them in order. If feeling cold comes with trouble thinking clearly, see brain fog.

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Citations

Educational context only, not medical advice or a diagnosis. Always discuss your results with a clinician.

Why am I always cold? The common causes of feeling cold and cold hands and feet, and the tests that check them