Compression Stockings for Blood Clots: What the Evidence Says

Many people ask whether compression stockings for blood clots are worth wearing, whether to prevent a clot, after surgery, on a flight or once a clot has already happened. The honest answer is that stockings have a place, but a narrower one than most people assume. This page sets out what current guidance and research say, in plain English, and where stockings can and cannot help.

How compression stockings work

Graduated compression stockings are tighter at the ankle and looser higher up the leg. The gentle pressure squeezes the leg veins, which helps blood move upward and reduces fluid building up in the tissues. That is why they help with swelling and aching legs. For a general introduction, see our compression stockings guide.

Whether that same effect reduces the formation of clots is a different question, and the answer is more complicated.

Can compression stockings prevent blood clots?

Clots in the deep veins (DVT) tend to form when blood flow slows, the vein lining is injured or the blood is more prone to clot. Stockings improve flow in the leg, so it seems logical that they would prevent clots. Research has not consistently backed that up in every situation.

• Hospital patients. Large trials in people who had a stroke did not show a clear reduction in clots with stockings, and they raised skin-problem concerns. Current NICE guidance on venous thromboembolism in hospital patients (NG89) advises against offering anti-embolism stockings as routine clot prevention, and favours other measures such as early movement, hydration and, where appropriate, preventive medicine or intermittent pneumatic compression devices. Individual hospitals and surgical teams may still choose differently for particular patients, so follow the plan you are given.
• After surgery. Practices vary by procedure and by patient risk. Stockings may form one element of a prevention plan but are rarely the only one.
• At home with no special risk. There is no good evidence that healthy people need stockings to prevent clots.

The takeaway is that stockings should not give a false sense of security. If you are at high risk of clots, your doctor will weigh medication, mobility and other measures, not stockings alone. Our guide to how to prevent DVT lists the approaches with the best support.

Compression stockings and long flights

Sitting still for hours can slow blood flow in the legs. Reviews of trials in travellers suggest that compression stockings may reduce ankle swelling and may lower the chance of small, symptom-free clots in the leg veins on long flights. The evidence on preventing serious clots is limited because those events are uncommon.

If you choose stockings for travel:

• get a correct fit, since poorly fitted stockings can roll down and cause more harm than good;
• walk the aisle, stretch your calves and ankles, and drink water;
• avoid heavy alcohol and sedatives that keep you still;
• ask your doctor first if you have had a clot, have poor circulation in the legs or have diabetes with nerve damage.

Compression stockings after you have had a DVT

Once a DVT has been diagnosed and treatment has begun, stockings can still be useful for comfort. Some people have a lasting swollen, heavy or aching leg after a clot, sometimes called post-thrombotic syndrome. Stockings may ease these symptoms.

NICE guidance (NG158) does not, however, recommend routine stockings to prevent post-thrombotic syndrome after a DVT, as trials did not show they reduce it. That means stockings are best viewed as a symptom aid for people who find them helpful, not as a protective treatment. Whether they suit you depends on your symptoms and your doctor’s advice. For how clots are treated, see deep vein thrombosis treatment.

Stockings are one tool among several

Clot prevention works best as a combination. Moving early after an operation or illness, avoiding long spells of sitting, staying hydrated, stopping smoking and managing weight all lower risk without any equipment. For people at higher risk, such as those having major surgery, doctors may add preventive medicine or leg-pumping devices used in hospital. Stockings, where they are used, sit alongside these steps rather than replacing them. If you are unsure which of these applies to you before an operation or a long trip, ask your doctor to explain your personal clot risk and what plan fits it.

What stockings cannot do

• They cannot dissolve a clot. Treatment of a diagnosed clot relies on prescribed anticoagulant medicine.
• They are not a substitute for medical assessment. A one-sided swollen leg needs a proper check, ideally with an ultrasound scan. See our page on blood clot in leg symptoms.
• They do not cure vein disease. They manage symptoms, which is covered in compression socks for varicose veins.

When stockings may be unsafe

Compression is not suitable for everyone. Check with a doctor first if you have:

• known or suspected severe arterial disease or poor blood supply to the legs;
• diabetes with reduced sensation in the feet;
• skin infection, fragile skin, weeping eczema or open wounds;
• heart failure with significant fluid overload;
• an allergy to materials such as latex.

Even people without these problems can get skin irritation, pressure marks or discomfort. Read more in compression stockings side effects. Stop wearing them and seek advice if you notice numbness, colour changes in the toes, skin damage or increasing pain.

Practical tips if your doctor advises stockings

• Have your legs measured, ideally in the morning, when swelling is lowest.
• Put them on smooth, without folds or rolled tops.
• Check your skin daily for redness or sores.
• Take them off if they feel painful, and replace worn-out pairs, since the elastic weakens over time.
• Do not assume they replace walking and moving regularly.

When to see a doctor

Call 995 immediately if you have sudden chest pain, sudden shortness of breath, coughing up blood or fainting. These may signal a clot in the lung.

See a doctor urgently, ideally the same day, if you have a leg that is newly swollen, painful, warm or red, especially on one side, or after surgery, a long journey, an injury or a period of being unwell in bed. Do not rely on stockings to settle it.

Also seek medical advice if you have had a clot before and are unsure whether stockings are right for you, if you are planning surgery or long-haul travel and want a clot-prevention plan, or if stockings cause skin damage, numbness or worsening pain.

This article is general information, not personal medical advice. Please speak to a doctor about your own symptoms. How we create our content.