Why are my veins are blue veins?

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blue purple and green veins on legs

If blood is red, why do veins appear as blue or green?

It’s a question that has crossed just about everyone’s mind now and then. There isn’t a single answer; in fact, there are many reasons why blue or green veins are visible through skin. Some of these include the varying wavelengths of different colors, your natural complexion, and even your Body Mass Index (BMI). You should also be aware that visible blue or green veins on legs can sometimes be a sign of trouble.

One common and potentially dangerous health condition that may be behind your visible veins is vein disease, or venous insufficiency. Vein disease is the underlying cause of painful, uncomfortable, and unsightly varicose veins and other venous issues.

Vein disease symptoms can include:

  • Swelling in your legs and ankles
  • Cramps or achiness in the thigh or calf
  • Tired or heavy legs
  • Restlessness, especially at night
  • Itchy, dry, or hardened skin on your legs
  • Wounds on your legs or ankles that take a long time to heal or don’t heal at all
  • Leg pain that goes away when you walk or elevate your legs

Below, we’ll answer some of your questions like,

Why are my veins so blue? and Why are my veins green? We’ll also discuss your overall circulatory system, when to see a doctor, and how to find non-surgical vein treatment.


Your Body’s Circulatory System

Let’s start by talking about how blood travels around your body. You are probably already aware that your heart is responsible for pumping blood, oxygen, and nutrients throughout. Arteries, capillaries, and veins are the blood vessels involved in this process.

Your arteries carry bright red, oxygen-rich blood from your heart to other regions of your body, including organs and tissue. Your capillaries’ job is to connect the arteries to your veins. Finally, your veins are responsible for delivering dark red, oxygen-depleted blood back to the heart for reoxygenation.

While arteries are found deep in the body, veins are generally close to the skin. Their location makes them more visible than other types of blood vessels. Some individuals, such as those with light complexions or aging skin, naturally have more visible veins. Others find that certain lifestyle factors can influence their veins’ appearance. For instance, those with a low Body Mass Index (BMI) due to weightlifting tend to have more visible veins.

Unfortunately, prominent blue or green veins are not always a sign of good health.

Visible blue veins on legs can be a sign of vein disease and should be evaluated by your doctor.

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Symptoms Quiz

facts about blood flow within your veins

Why Are My Veins Blue or Green Veins?

Blood pumping away from your heart is bright red, and blood pumping back to your heart is dark red. So, why are veins green or blue?

This visual phenomenon is due to how our eyes perceive the different wavelengths of light. Red light has the longest wavelength, violet light the shortest, and other colors are in between. White light contains all colors and wavelengths.

When white light hits the skin, red light can travel further below the surface than blue light. Its longer wavelength reaches deeper where your veins are located. From there, hemoglobin –– the protein that makes your blood red –– absorbs the red light.

Blue or green light, on the other hand, doesn’t travel as deeply. They are more easily deflected from your skin than red light. So when white light hits your skin, blue and green light isn’t absorbed in the same way as red light. The result is that, despite blood always being red, you ultimately see blue or green veins.

You may also be wondering about blue vs. green veins. The exact hue that your veins appear depends on several factors. These factors include your skin tone, BMI, age, and how deep the veins are located.

Why Are My Veins So Visible?

why do veins often appear blue or green beneath the skin's surface

Should I Worry About My Visible Blue Veins?

Just because you have visible blue veins on legs does not mean you need to race to the emergency room. However, there are specific symptoms that you should be on the lookout for. These include any pain and discomfort due to leg swelling, cramping, heaviness, or odd sensations like itching and burning. If your blue veins are symptomatic and raised above the skin, they are probably varicose veins.

Varicose veins are not only a cosmetic issue. They are also a sign that your body’s circulatory system is not working properly. When vein valves malfunction, they can no longer effectively pump blood back to the heart. This results in blood pooling, most often in the legs, ankles, and feet. Varicose veins can also put you at risk for potentially dangerous health conditions.

If you notice sudden prominent blue veins, we recommend seeking care immediately. The sudden appearance of visible blue veins accompanied by pain, swelling, tenderness, discoloration, and warmth can indicate Deep Vein Thrombosis (DVT). DVT is considered a medical emergency. Another type of blood clot, called Superficial Thrombophlebitis (ST), can also occur and requires urgent medical attention.

One other serious issue to look for is the development of venous ulcers, or non-healing wounds on the leg. Venous ulcers require treatment since they can put you at risk for skin and blood infections. The most effective treatment involves addressing the underlying cause –– your vein disease.

Vein Disease and Treatment

Problematic veins are not always visible. You may experience painful vein symptoms like swelling or cramping with no sign of visible blue or green veins. Or, your malfunctioning veins may be visible, but not protrude or appear enlarged. The presence of tiny, painless spider veins, for example, can be an early sign of vein disease.

In general, you may be at higher risk for vein disease if you are:

  • Female
  • Over age 50
  • Pregnant
  • Hypertensive
  • Diabetic
  • Closely related to someone with varicose veins
  • Regularly standing or sitting for prolonged periods of time

If you have any concerns about your vein health, it is important to consult a vein specialist. They can review your symptoms and perform an ultrasound to look for malfunctioning veins. If you are at high risk for vein disease, your doctor will want to closely monitor you for early signs.

Fortunately, you can explore several minimally invasive-vein treatments that can quickly return you to normal activities. These include:

Contact USA Vein Clinics

We hope you now have a better understanding of why your veins might be green or blue. Next, we want you to know a little more about us. Our vein specialists perform minimally-invasive, office-based treatment for varicose veins, spider veins, restless leg syndrome, and other venous conditions. Most of our treatments take only 15 to 30 minutes and allow you to leave immediately afterward.

In other words, there’s no need to worry about green or blue veins anymore. Head to one of our state-of-the-art clinics which are conveniently situated nationwide over 90 easy-to-find locations. To learn more about your vein health, just schedule an appointment online or call us at 888.768.3467. We look forward to helping you alleviate any painful or uncomfortable vein symptoms!

Talk to a Vein Expert


Reviewed by Dr. Yan Katsnelson, the founder and CEO of USA Vein Clinics. Dr. Katsnelson is a highly skilled cardiac surgeon who completed a fellowship at the Brigham and Women’s Hospital, Harvard School of Medicine, in Boston, MA. His clinical area of expertise includes minimally invasive procedures to treat vein and vascular diseases. Dr. Katsnelson has established himself as a strong advocate for accessible, affordable, and compassionate healthcare services.

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