Horse chestnut (Aesculus hippocastanum) is a fruit-bearing tree grown in southeastern Europe. The leaves, seeds, flowers, and bark of horse chestnut contain bioactive compounds that may benefit human health. For example, some people take horse chestnut to relieve joint pain or leg cramps.

Compounds in horse chestnut include antioxidants, chlorophylls , and saponins, the most abundant of which is escin. While it is unsafe to consume horse chestnut in raw form, supplements are available and have been studied for their potential use in treating a variety of health conditions, including chronic venous insufficiency (CVI), and irritable bowel syndrome (IBS).

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Uses of Horse Chestnut

Traditionally, horse chestnut has been used for:

• Joint pain
• Fever
• Leg cramps
• Bladder or stomach issues
• Hemorrhoids
• Varicose veins
• Bruises

These days, horse chestnut has been researched for its potential role in chronic venous insufficiency, irritable bowel syndrome, and other conditions. However, scientific evidence supporting these uses is minimal.

Some research has been performed on horse chestnut as an alternative treatment for poor circulation, sports injuries, and male infertility. The next sections will outline these potential uses further.

May Improve Symptoms of Chronic Venous Insufficiency (CVI)

According to research, horse chestnut has anti-inflammatory properties that may be beneficial for those with CVI. This may be due to one bioactive component of horse chestnut called aescin (escin).

According to one review, results from both lab studies and clinical trials have found horse chestnut to have a positive effect on CVI. Studies included in the review reported improvements in leg pain, itching, fatigue, and edema as a result of horse chestnut use.

In some studies, horse chestnut produced similar relief as compression therapy (applying gentle pressure to the leg). Horse chestnut was also safe for most participants, with no side effects reported across studies within the review.

Few other studies have been performed on horse chestnut for CVI since this review was published in 2015. Updated research should be conducted to continue to further explain horse chestnut's role in CVI.

Promotes Healing From Certain Injuries

Some research has looked at the effects of escin on sports injuries.

A review of escin found that topical forms of the compound improved bruises and other blunt lesions caused by playing sports. Using topical escin has been associated with better mobility, reduced swelling, and reduced pain in small-scale human trials.

Additional studies, including large-scale human trials, would strengthen these claims and further prove whether horse chestnut plays a role in healing from certain injuries.

May Treat Male Infertility

A small amount of research has shown that horse chestnut may improve symptoms of male infertility.

According to a review of alternative treatments for male infertility, escin has antioxidant and anti-inflammatory properties linked to improvements in male fertility.

Specifically, escin may improve fertility in males with varicocele-associated infertility, which is characterized by blocked or enlarged veins surrounding the testes.

Another study included 219 males with varicocele-associated infertility who were randomly placed into three groups: a control group, a surgery group, and an escin group.

Participants in the escin group took escin orally at 60 milligrams (mg) daily for two months. Those who took escin had more significant improvements in vein size and sperm health than the control group, but not the surgery group.

More research is necessary to determine whether horse chestnut and its bioactive compounds can improve male infertility.

What Are the Side Effects of Horse Chestnut?

Overall, horse chestnut supplements are generally safe and well-tolerated by most people.3 However, some people may experience side effects when using horse chestnut. These side effects can be mild or severe.

Common Side Effects

Most people don't experience side effects when using horse chestnut, but some do. Side effects associated with horse chestnut use include:

• Dizziness
• Nausea
• Upset stomach

Other side effects may be possible but are not well-documented in the available research.

Typically, your risk of side effects increases with improper supplement use. Taking high doses or using horse chestnut for too long may increase this risk.

Severe Side Effects

Consuming the raw fruit, seeds, bark, flowers, or leaves of the horse chestnut tree may cause severe side effects. These severe side effects can include:

• Liver damage
• Heart palpitations
• Urticaria  (hives or welts on the skin)
• Respiratory distress
• Acute anaphylaxis  (when applied to the skin)

Instances of severe reactions to horse chestnut are very rare. Yet, it's important to be aware that such side effects are possible.

Precautions

Horse chestnut may not be right for everyone. Some people should avoid using horse chestnut for various reasons.

Again, no one should ever consume raw horse chestnut, including the fruit, seeds, flowers, leaves, or bark. Consuming raw horse chestnut may lead to toxicity.

Horse chestnut may not be safe for people who are pregnant or breastfeeding. There is simply not enough scientific evidence on the use of horse chestnut in these populations to know whether it is safe. Pregnant or breastfeeding people should also avoid using products that contain extracted bioactive compounds of horse chestnut (like escin).3

There isn't enough evidence to know if horse chestnut is safe for children. It's best to play it safe and avoid giving your children horse chestnut.

People with medical conditions or who take prescription medications should talk with a healthcare provider before using horse chestnut. It may make certain conditions worse or negatively interact with some medications. Although, there is no strong evidence regarding people with medical conditions using horse chestnut.

Dosage: How Much Horse Chestnut Should I Take?

There isn't much dosage information for horse chestnut supplements. This is due to the overall lack of research on horse chestnut.

A wide range of dosages has been used in research on horse chestnut. For example, while 600 mg of horse chestnut seed extract has been a common dose for studies on CVI, participants in these studies used horse chestnut for anywhere between two and 16 weeks.

Additionally, many studies on horse chestnut have been performed on animal models, making determining proper human dosage challenging.

More research is necessary before a dosage can be standardized. Until then, follow the dosage directions on the label of your horse chestnut supplement. You can also seek guidance on how much to take from a healthcare provider or registered dietitian nutritionist (RDN).

What Happens If I Take Too Much Horse Chestnut?

Little is known about safe dosing or long-term use of horse chestnut.

Horse chestnut is considered safe for most people who follow dosing directions and only use it for short periods. However, taking too much horse chestnut may increase your chance of side effects like dizziness, nausea, and upset stomach.

Remember never to consume raw parts of the horse chestnut tree, as doing so can lead to toxicity. Eating raw horse chestnut has reportedly led to liver damage, respiratory distress, heart palpitations, and acute anaphylaxis.

Interactions

Many supplements run the risk of interacting negatively with certain medications or other supplements or herbs.

There isn't much research on interactions between horse chestnut and any medications, supplements, or foods. However, a few possible interactions exist.

Horse chestnut may interact with warfarin, a blood-thinning medication, but there is no strong evidence of this interaction. In fact, an interaction between horse chestnut and warfarin was labeled as "doubtful" in a 2014 review of the medication.

There is some concern that horse chestnut may interact with medications or supplements that have similar actions, such as treating CVI, edema, sports injuries, and male infertility. For this reason, you should avoid taking horse chestnut if you are already taking medications for these conditions or any others that may be affected by horse chestnut.

Because interactions are not well-documented for horse chestnut, it's important that you talk with a healthcare provider before using it if you take any prescription medications or other supplements.

How to Store Horse Chestnut

Storing horse chestnut supplements properly will help maintain their shelf-life.

Some supplement labels may provide storage directions. Otherwise, store horse chestnut supplements in a cool, dry place and keep them out of direct sunlight. There is no need to refrigerate horse chestnut.

Keep supplements in their original bottle or packaging, and ensure the lid is airtight.

Be sure to store horse chestnut and other supplements in places pets or small children can't reach.

Discard your supplements once they have expired. Expiration dates should be listed on the container or original packaging.

Similar Supplements

Certain supplements may have similar uses as horse chestnut. Similar supplements include:

• Red vine leaf: An extract from red vine leaf has been found to improve symptoms of CVI. One systematic review concluded that red vine leaf extract may play a therapeutic role in CVI.
• Pycnogenol : A trademarked name for pine trees that grow in southwest France, Pycnogenol is a bark extract that may also help treat CVI. Using oral Pycnogenol supplements has been associated with reduced leg pain, leg heaviness, and swelling in people with CVI and other circulatory conditions.
• Vitamin C: Vitamin C is an antioxidant that fights free radicals and helps your body repair damage. Vitamin C may even help bruises heal faster. This is thought to be due to both the antioxidant properties of vitamin C as well as its important role in the production of collagen, the protein most responsible for building and maintaining healthy skin.
• Fenugreek: Like horse chestnut, fenugreek (a type of herb) may have a positive effect on male infertility. A study of 100 healthy males found the fenugreek seed extract improved sperm motility, testosterone levels, and the overall health of sperm.13 It's worth noting that fenugreek is not necessarily meant to treat varicocele-associated infertility (the inability to conceive due to blocked and enlarged veins around the testes that raise the temperature within the scrotum and decrease the production of sperm).

Typically, it's best to use just one supplement at a time for a health condition. Talk with a healthcare provider about which supplement may be right for you.

Sources of Horse Chestnut & What to Look For

Some people use horse chestnut as a dietary supplement to improve their health. But it's important to remember that more research is needed regarding safety and efficacy, as well as that some health claims about horse chestnut's benefits are unfounded.

Food Sources of Horse Chestnut

Horse chestnut is not found in foods and should never be eaten raw. Cooked horse chestnut should also not be consumed.

The only way to safely consume horse chestnut is through supplements that have removed toxic compounds naturally found in the tree.

Horse Chestnut Supplements

It's easy to find horse chestnut supplements for sale online. You may also be able to find horse chestnut supplements in specialty health or supplement shops. However, horse chestnut is not widely available in grocery or retail stores.

Oral horse chestnut supplements are mostly sold as tablets or capsules. There are also topical horse chestnut options, including creams, oils, and gels.

Be sure to read the ingredients list and nutrition label, as some supplements contain horse chestnut along with other nutrients or ingredients. The nutrition label should also tell you if the supplement is vegan, kosher, organic, and/or gluten-free.

Summary

Horse chestnut (Aesculus hippocastanum) is a type of tree with potentially beneficial compounds in its bark, leaves, flowers, and fruit.

Some research has been done on the use of horse chestnut for conditions like CVI, edema, injuries, hemorrhoids, and male infertility. And while some evidence is promising, more research is needed overall to better determine the safety and efficacy of horse chestnut.

Horse chestnut should only be used in supplement form and never be consumed raw or cooked, or eaten straight from the tree. Talk with a healthcare provider or RDN if you have more questions about horse chestnut.