Does Smoking Cause Blood Clots?

Unless you have been living under a rock, you will know that smoking cigarettes is associated with a lot of different health problems.

In a lot of countries, some of these health issues are printed on the cigarette packet, with serious warnings in bold writing, and graphic images. That is why you know that smoking isn’t good for you. 

However, there are lots of health issues associated with smoking that you don’t really hear much about. These are mainly the health issues that do not focus on your lungs and respiratory system. Such as blood clots. 

Blood clots are incredibly dangerous, and they are associated with lots of other serious conditions. But does smoking have a link with blood clots? In this guide, we’ll take a look if smoking can cause blood clots, and lots more. So to find out more, keep on reading. 

What Are Blood Clots?

First, let’s take a look at what blood clots are. As you probably already know, blood clots are a serious health condition that is linked with lots of other serious conditions.

Blood clots are formed when blood coagulates, and they are the final step in hemostasis. Sometimes, you will also hear a blood clot referred to as a thrombus. 

Blood clots form when your blood begins to thicken. While blood usually has a liquid consistency, it can thicken. When this happens, the blood will form a semi-solid mass. A mass that is soft to the touch, but hard enough to cause issues.

This is primarily because blood clots will travel through your veins and arteries as though they are normal blood, even though they are very different. 

Blood clots do not magically appear, something must happen to trigger them. Most of the time, there will be an injury that triggers the thickening process. However, it is not always possible to pinpoint the injury that triggered this.

That is why some people think that blood clots come out of nowhere. But, most of the time, you will be able to trace them back to a trigger. But could this trigger be smoking? Let’s take a look.  

Does Smoking Cause Blood Clots?

So, your blood coagulates and forms blood clots when it is triggered to do so. These triggers are usually caused by trauma or injury, however sometimes, pinpointing the damage can be a little more tricky.

This is because blood clots can sometimes be caused by things that we put into our body. For example, a lot of oral contraceptive pills list blood clots as a possible side effect. So, if hormonal birth control can cause blood clots, can smoking?

There is evidence that smoking can cause blood clots. There are a lot of studies that show that smoking cigarettes will increase your risk of blood clots.

Similar to how taking most contraceptive pills will increase your risk of blood clots. As we know, blood clots are caused by trauma, and smoking cigarettes causes a lot of trauma to your body. 

When you smoke cigarettes, the ingredients in the cigarettes cause damage to the lining of your blood vessels. As the blood vessels become damaged, the blood becomes more likely to thicken which then causes blood clots.

Likewise, the ingredients in cigarettes also cause the platelets of your blood to fuse together, making your blood thicker, and increasing your chances of experiencing blood clots even further. 

How Likely Is It To Get Blood Clots From Smoking?

So, smoking does increase your risk of experiencing blood clots. But, by how much does it increase? Well, that depends on how often you have smoked.

Not only is your risk of blood clots increased if you currently smoke, but your risk of blood clots will increase if you have ever smoked. At least that is what one study by Sun Yat-sen University in China has found.

This study found that people who have smoked in their lifetime had a much higher risk of blood clots than people who have never smoked. In fact, their risk of blood clots is 17% higher in those that have smoked than those who have not smoked.

This risk increases even further if you are an individual who currently smokes. However, this increase is not too large. If you currently smoke regularly, then you have a 23% higher risk of developing blood clots than non-smokers, according to the study. 

It is important to remember that this is just one study, and that this study only used 184 patients which is a relatively low sample.

However, this study does confirm that your risk of developing blood clots is increased if you are a smoker. Especially if you are somebody who currently smokes. 

Why Do Cigarettes Cause Blood Clots?

As we said earlier, cigarettes increase your risk of blood clots because of the ingredients used in cigarettes. There are a lot of unpleasant ingredients used in cigarettes, but the ingredient that does the most damage is Nicotine.

This is not only because Nicotine is the ingredient in cigarettes that is addictive, but also because Nicotine is the ingredient in cigarettes that causes blood clots. 

Blood clots are linked to smoking because smoking Nicotine changes your blood platelets, and this change causes the platelets to stick together. When platelets stick together, they thicken the blood, which then leads to blood clots.

In addition, Nicotine also causes damage to the lining of the blood vessels. As this lining becomes damaged, it will often break away into the bloodstream.

These loose pieces of lining will then fuse with platelets, leading to a blood clot. So, smoking increases the risk of blood clots because it affects the blood in two ways. 

However, Nicotine can also increase your risk of blood clots because of the hormones associated with Nicotine. In particular, Nicotine impacts the amount of adrenaline that is in the body.

Increased levels of adrenaline are also linked with blood clots. So, as you can see there are lots of different ways that smoking is linked with blood clots.

Can Quitting Smoking Cause Blood Clots?

However, if you have considered quitting smoking, you have probably heard of the negative side effects associated with this. Especially if you quit cold turkey.

There are lots of unpleasant side effects to suddenly stopping smoking, including weight gain, increased appetite, restlessness, craving, and irritability. However, blood clotting is not a side effect that is typically associated with quitting smoking. 

As we said earlier, there will be an increased risk of blood clots if you have ever smoked. But, there is evidence that your risk of illnesses associated with blood clots is reduced as time passes from the date you quit smoking.

For example, your risk of stroke reduces significantly once 5 years have passed from the day you quit smoking.

In fact, some studies have found that your risk of stroke from smoking reduces to the same level as a non-smoker once you have not smoked a cigarette for 5 years. Strokes are caused by blood clots, so your risk of these must also decrease.


In short, yes, smoking can cause blood clots. This is because the ingredients used in cigarettes cause damage to the lining of blood vessels, and also the platelets too.

These changes increase the risk of blood clots forming, especially when combined with the fact that Nicotine increases the level of adrenaline hormone in your body.

So, yes, your risk of blood clots does increase when you smoke. But, when you give up smoking, these risk levels do reduce. Even if you have smoked heavily in the past.

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