Sclerotherapy FAQ: What Do Doctors Inject Into Spider Veins?

doctor shows dilation of small blood vessels

Table of Contents

  • How Sclerotherapy Works
  • What Do Doctors Inject Into Spider Veins? 
  • Benefits of Sclerotherapy 
  • How to Prepare for Sclerotherapy

When it comes to removing and reducing the appearance of spider veins, there are multiple options to get the job done. One of the most common treatments for spider veins is sclerotherapy. Sclerotherapy is a procedure that involves injecting a solution into your vein(s) to eliminate spider and small varicose veins. Sclerotherapy is a minimally invasive, simple procedure that brings numerous benefits to patients.1 To learn more about this procedure, the benefits of Sclerotherapy, and how to prepare for your appointment, continue reading below.

How Sclerotherapy Works

During a sclerotherapy procedure, a doctor injects a solution directly into the spider or varicose vein. The solution then causes the vein to swell and block the flow of blood here. The vein then scars, rerouting the blood into separate, healthier veins. The injected vein then starts to fade as it gets reabsorbed into one’s tissue. The results of sclerotherapy typically take a couple weeks to one month to appear. In some cases, multiple treatments are needed for successful results.2

The procedure itself is relatively simple and fast, requiring no anesthesia and typically taking under one hour to complete. When treating spider veins in the legs, you lie down with your legs elevated, and your doctor will insert a liquid or foam solution in the targeted vein. After the injection, your doctor compresses and/or massages the area to further restrict blood flow, and they may apply a compression pad. For multiple veins, your doctor continues this process for each.

After the procedure, patients are advised to stay moving to prevent any blood clots, as well as wear compression stockings for a period of about two weeks. Sclerotherapy typically has few side effects, with bruising, sores, and darkened skin around the site of treatment being the most common, temporary side effects. However, some more serious side effects may occur, such as inflammation, blood clots, and allergic reactions.3 Proper preparations before your procedure can help to ensure your treatment goes smoothly, as detailed below.

What Do Doctors Inject Into Spider Veins? 

The solution injected into a patient’s spider veins varies among a few options. The most common solutions are:

  • Sotradecol (sodium tetradecyl sulfate)
  • Asclera/Aethoxysklerol (polidocanol)

Both of these detergents disrupt the vein’s cellular membrane, causing it to scar and close.4 A solution called “hypertonic saline” (salt water) used to also be a common solution for sclerotherapy, but it is used less frequently today, as it tends to cause discomfort and stinging for patients. Hypertonic saline may be a better option for those who have allergies, though. 

Additionally, the chosen solution may be in liquid or foam form. A foam solution may have a better chance of successfully sealing veins, but liquid solutions also have high success rates. The choice of solution and consistency may depend on the vein size, location on the body, patient’s allergies, and other factors.

Sotradecol and Asclera/Aethoxysklerol may be more expensive than hypertonic saline, but they are more likely to provide a comfortable experience for patients. Both solutions are equally effective and FDA approved. They are far less likely to be painful when injected. These solutions are also able to be made into foam, which is more effective for larger veins.

Benefits of Sclerotherapy 

Sclerotherapy brings many benefits to patients. Overall, the treatment is very simple and minimally invasive. Depending on the patient and solution used, the procedure is also generally painless, resulting in mild discomfort at most.5 This nonsurgical procedure requires no downtime, and it results in an easy recovery process. Sclerotherapy also has a high success rate of around 60% to 80%.6

Another major benefit of sclerotherapy is, of course, that it reduces the appearance of spider veins. This cosmetic benefit can increase the self-confidence and quality of life for patients who have dealt with visible spider and varicose veins. Additionally, if patients have experienced other symptoms associated with their spider and varicose veins, such as aching, swelling, burning, or night cramps, sclerotherapy can reduce or eliminate those discomforts entirely.

How to Prepare for Sclerotherapy

There are a few things you can do to prepare for sclerotherapy. First, your vein specialist performs preparations like examining your veins, evaluating your medical history, and perhaps performing an ultrasound to view the structures around your veins.7 

Your doctor may ask about the following aspects of your medical history:

  • Medical conditions, such as a history of blood clots or heart issues
  • Regular medications taken, such as aspirin, ibuprofen, naproxen sodium, blood thinners, and supplements
  • Allergies, such as to a detergent or medication
  • Previous vein treatment history

As for personal preparations, patients are advised to do the following before a sclerotherapy appointment:

  • Avoid shaving your legs or the area of treatment
  • Avoid using lotion on the area of treatment
  • Wear loose clothing and/or shorts
  • Eat a meal or snack and stay hydrated

When deciding if sclerotherapy is the right vein treatment for you, consider the size of your veins, your budget, and vein specialists near you. To learn more, you may consult with a specialist to answer any questions or concerns about your treatment. My Vein Treatment has a vein specialist locator to help you find a specialist in your area, so you can decide if sclerotherapy is the right treatment for your spider and varicose veins.


  1. Mayo Clinic: “Sclerotherapy.”
  2. Medical News Today: “What is sclerotherapy? Uses, price, what to expect, and all else you need to know.”
  3. Cleveland Clinic: “Sclerotherapy.”
  4. Phlebology: The Journal of Venous Disease: “Evaluation of sodium tetradecyl sulfate and polidocanol as sclerosants for leg telangiectasia based on histological evaluation with clinical correlation.”
  5. Vein Institute: “The Benefits of Sclerotherapy.”
  6. WebMD: “Sclerotherapy for Spider and Varicose Veins.
  7. CardioVascular and Interventional Radiology: “Effectiveness of sclerotherapy, surgery, and laser therapy in patients with venous malformations: a systematic review.”

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