Horse chestnut, or Aesculus hippocastanum, is a tree native to the Balkan Peninsula.

Extract from the horse chestnut seed is a popular dietary supplement commonly used to improve vein health and reduce inflammation.

The main active component in horse chestnut extract is aescin, which has been studied for its many health benefits.

Here are 7 health benefits of horse chestnut extract.

Horse Chestnut BenefitsShare on Pinterest

Chronic venous insufficiency (CVI) is a health condition characterized by poor blood flow to the veins of the legs.

Symptoms can include (1):

  • edema, or swelling of the legs
  • leg pain or cramps
  • itchy legs
  • varicose veins, or enlarged, twisted veins that typically occur in the legs
  • leg ulcers
  • weakness in the legs

A common treatment is compression therapy or stockings, which can increase blood flow to your legs.

The compound aescin in horse chestnut has multiple medicinal properties that could make it useful for treating CVI. For example, it may increase blood flow in your veins, possibly improving symptoms (2, 3, 4).

In a review of 19 studies, 9 studies found that daily doses of 600 mg of horse chestnut extract containing 50 mg of aescin taken for up to 8 weeks reduced symptoms of CVI, including leg pain, swelling, and itchy legs (5).

In fact, one study noted that horse chestnut extract was as effective as compression therapy at reducing swelling and leg volume (6).

These studies show that horse chestnut extract may be effective for treating CVI short term, but more research is needed to determine its long-term effects.

Summary Horse chestnut extract may be an effective short-term treatment for CVI, a condition that can cause varicose veins, swelling of the legs, and leg pain.

Varicose veins are swollen, bulging veins that typically occur in the legs and can be caused by CVI.

Horse chestnut seed extract may improve venous tone by improving blood flow in your legs (7, 8).

Additionally, it may help decrease leg swelling and pain associated with varicose veins (2).

In an 8-week study, 58% of participants who took horse chestnut seed extract tablets containing 20 mg of aescin 3 times daily and applied 2% aescin gel topically twice daily had reduced varicose vein symptoms like leg pain, swelling, heaviness, and discoloration (4).

Summary Horse chestnut seed extract may improve blood flow and help treat varicose veins, which are bulging veins in the legs.

Inflammation can cause excess fluid buildup in your tissues, which can lead to fluid retention and swelling (9).

Aescin is a component in horse chestnut extract with anti-inflammatory properties. It has been found to reduce inflammation related to injury, venous insufficiency, and swelling (10, 11, 12, 13).

A review of 17 studies observed that horse chestnut seed extract could help reduce inflammation and swelling in the legs and feet related to CVI (2).

In addition, studies showed that applying a topical ointment containing aescin could reduce inflammation and swelling after trauma, surgery, and sports injuries (14, 15).

However, this ointment also contained other anti-inflammatory compounds, making it unclear whether aescin alone would have the same effects.

Summary Inflammation can cause swelling and fluid retention. Horse chestnut seed extract may reduce inflammation related to chronic venous insufficiency, trauma, surgery, or injuries.

Hemorrhoids are a common health condition characterized by swollen veins around your anus and rectum.

Symptoms are uncomfortable and can include itching, irritation, pain, and rectal bleeding (16).

The anti-inflammatory properties of horse chestnut seed extract may help relieve symptoms of hemorrhoids by reducing inflammation and swelling in the affected veins (17).

Still, research in this area is limited and more studies are needed to confirm the potential benefits of horse chestnut extract for treating hemorrhoids.

Summary Horse chestnut extract may help relieve hemorrhoid symptoms by reducing pain and swelling, but more research is needed.

Horse chestnut seed extract contains powerful antioxidants — compounds that can help prevent cell damage caused by unstable molecules called free radicals. Too many free radicals can lead to inflammation and cellular damage (18).

Horse chestnut seed extract is rich in flavonoid compounds, including quercetin and kaempferol, which have potent antioxidant properties (19).

A test-tube study found that both aescin and horse chestnut seed extract have antioxidant properties, but that the horse chestnut seed extract had greater effects than aescin alone. This may be due to the synergistic effects of the components in the extract (20).

Summary Horse chestnut seed extract contains antioxidants that may help protect against cellular damage caused by free radicals.

Aside from its powerful anti-inflammatory properties, test-tube studies also indicate that aescin has anticancer effects.

These studies found that aescin could significantly reduce tumor cell growth in certain cancers like liver cancer, leukemia, and multiple myeloma (21, 22).

In addition, test-tube studies observed that aescin can cause cell death in cancerous cells like pancreatic cancer and lung cancer (23, 24).

However, these studies used concentrated amounts of aescin, and it’s unclear whether the amount found in horse chestnut seed extract would have the same effects. More human studies in this area are needed before firm conclusions can be made.

Summary Horse chestnut may have anticancer effects. Still, more research in this area is needed before strong conclusions can be drawn.

One of the causes of male infertility is varicocele, or swelling of the veins near the testicles (25).

The anti-inflammatory and anti-swelling properties in aescin — a compound in horse chestnut — may make it an effective treatment for infertility related to varicocele (26, 27).

A 2-month study in over 100 men with varicocele-associated infertility found that taking 30 mg of aescin every 12 hours improved sperm density, sperm motility, and sperm quality. In addition, the varicocele size decreased with the intake of aescin (28).

Summary Swelling of the veins near the testicles can cause infertility. A compound in horse chestnut extract has been found to improve sperm quality and decrease varicocele in men with varicocele-associated infertility.

While the use of horse chestnut seed extract is generally considered safe, you should be aware of some safety concerns and side effects.

Unprocessed horse chestnut seeds contain a compound called aesculin, which is considered unsafe to ingest by the Food and Drug Administration (FDA). Signs of poisoning include depression, muscle twitching, paralysis, coma, and death (3, 29).

For this reason, avoid ingesting unprocessed horse chestnut seeds.

Reported side effects of horse chestnut seed extract are mild and include digestion issues, upset stomach, dizziness, headache, and itching. Additionally, there have been reports of allergic reactions when horse chestnut extract was applied to the skin (2, 30).

What’s more, horse chestnut extract may interact with the following medications (3):

  • Blood thinners. Horse chestnut may slow blood clotting and increase the effects of blood thinners like Coumadin.
  • Insulin or oral diabetes medicine. Horse chestnut may lower blood sugar and cause levels to become too low if taken with diabetes medication.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs). Horse chestnut may reduce the absorption of NSAIDs, which are drugs used to treat inflammation.
  • Lithium. Horse chestnut may have a diuretic effect, which could delay how fast your body processes lithium, a medication used to treat psychiatric disorders.

In addition, people with kidney or liver disease should not take horse chestnut as it may exacerbate symptoms of their disease (3).

For these reasons, always consult with your healthcare provider before taking horse chestnut extract — especially if you have a medical condition or are currently taking medications.

Furthermore, the safety of using horse chestnut extract during pregnancy and breastfeeding is unknown, and the supplement should, therefore, be avoided by women who are pregnant or breastfeeding.

Summary Horse chestnut seed extract is generally safe to take or use topically. However, there are some reported side effects, interactions with certain medications, and safety concerns associated with certain medical conditions.

Horse chestnut can be found in stores and online in the form of capsules, tablets, liquid drops, essential oil, and cream.

Horse chestnut extract typically contains 16–20% aescin. In most studies, the dosage used is 100–150 mg of aescin per day. Hence, potential toxic effects of higher doses are unknown. Therefore, it’s best to follow suggested dosing instructions (2, 30).

This amounts to about 2–3 tablets or capsules per day. There is no standardized recommendation for liquid supplements. Further dosing information is usually available on supplement bottles.

When applied topically, extracts and creams usually contain 2% aescin and can be applied 3–4 times per day (2, 30).

Summary The beneficial dosage of horse chestnut seed extract appears to be 100–150 mg of aescin per day in supplement form and 3–4 daily applications of cream or extract when applied topically.

Horse chestnut extract has powerful anti-inflammatory properties and may help relieve pain and inflammation caused by chronic venous insufficiency (CVI).

It may also benefit other health conditions like hemorrhoids and male infertility caused by swollen veins.

The anti-inflammatory and antioxidant properties of horse chestnut make it a popular natural treatment for a variety of conditions.

The extract is generally considered safe to take but comes with potential side effects and may interact with certain medications. Therefore, consult with your healthcare provider before taking horse chestnut extract.