What Is Bugleweed?

Commonly Used in the Treatment of Thyroid Conditions

Bugleweed dried herb, capsules, and tincture

Verywell / Anastasia Tretiak

Bugleweed (Lycopus europeus) is a perennial herb in the family Lamiaceae. It is distributed throughout Asia and Europe and it has become acclimated to North America. The plant is a perennial flowering species with deep purplish-blue- colored flowers that bloom from May to September (depending on geographic location), and the seeds ripen from July to September. Bugleweed has many traditional uses ranging from suppressing coughs to improving symptoms associated with hyperthyroidism.

Several plants are known as "bugleweed." For example, Lycopus europaeus (European bugleweed) is native to Eurasia and Asia. Lycopus americanus (American bugleweed) is native to North America.

This article discusses the traditional uses of bugleweed and its medicinal properties. It also covers special considerations and any side effects.

Dietary supplements are not regulated in the United States, meaning the FDA does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement that has been tested by a trusted third party, such as USP, ConsumerLab.com, or NSF International. However, even if supplements are third-party tested, that doesn't mean that they are necessarily safe for all or effective in general. It is important to talk to your healthcare provider about any supplements you plan to take and to check in about any potential interactions with other supplements or medications.

Supplement Facts

  • Active ingredient(s): tannins, flavonoids, rosmarinic acid
  • Alternate name(s): European bugleweed, gypsywort
  • Legal status: herbal supplement
  • Suggested dose: no official suggested dose for bugleweed
  • Safety considerations: use in pregnancy, breastfeeding, thyroid conditions, and endocrine disorders

Uses of Bugleweed

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or doctor. No supplement is intended to treat, cure, or prevent disease.

Bugleweed contains many extracts, chemicals, and oils, making it an attractive plant for many conditions and illnesses. Scientists have studied many of these properties, but there is still no proof of health treatment claims. More research must be completed to understand how bugleweed works and its effectiveness. Common uses that have yet to be proven by scientists include but are not limited to:

  • Hyperthyroidism
  • Coughs
  • Sleeplessness

There is not enough human data to support bugleweed's use for the following:

  • Analgesic (pain reliever)
  • Antidiarrheal (stops diarrhea)
  • Antimicrobial (destroys or stops bacteria, fungi, and virus growth)
  • Antioxidant
  • Antiparasitic (destroys or prevents parasite growth)
  • Anti-inflammatory (stops inflammation)
  • Dermatological (skin) effects

Since the studies used are mostly animal (e.g., rat or mouse) studies, there is no proof of bugleweed's effectiveness in humans. We will focus on studies that use bugleweed to treat or prevent hyperthyroidism, coughs, and sleeplessness.

Hyperthyroidism

Hyperthyroidism is an overactive thyroid. A common form of hyperthyroidism is Graves' disease. This form of hyperthyroidism is evident with the presence of a goiter. Other symptoms may be high body temperature, a high rate of metabolism, and an increased pulse.

Although studies have discovered favorable outcomes for using bugleweed to improve symptoms of hyperthyroidism, most of the research has been conducted on animals like rats—not humans.

That said, one study surveyed 403 patients with mild symptomatic hyperthyroidism receiving drug therapy with the main ingredient of Lycopus europaeus, or European bugleweed. The study revealed the medicine was well tolerated and that Lycopus europaeus showed a clinically relevant improvement in mild hyperthyroidism symptoms.

Though one study had positive results, more clinical studies must be done to understand how bugleweed affects hyperthyroidism.

Coughs

The traditional use of bugleweed for treating coughs and upper respiratory issues remains unfounded.

There are no clinical studies in humans supporting these effects. Research proving this effect has been completed only in mice. More clinical (human) studies must be done to validate these claims.

Sleeplessness

Another traditional use for bugleweed is to help with sleeplessness. Its sedative effect is believed to be from flavonoids present in bugleweed. However, these findings are from a rat study, which is not enough evidence to support this use.

What Are the Side Effects of Bugleweed?

Bugleweed has no known side effects. There have been limited studies that include side effects in humans. One study did demonstrate that bugleweed was well tolerated.

Common Side Effects

Though there are no documented side effects of bugleweed, there is the risk of an allergic reaction with all herbal supplements. Signs of an allergic reaction may include:

  • Hives or welts
  • Swelling of the lips, face, or eyes
  • Tingling of the mouth
  • Headaches
  • Abdominal pain, nausea, and vomiting

Anyone who experiences allergic symptoms after taking bugleweed should immediately stop taking the herb and contact a physician or other healthcare provider.

Severe Side Effects

Bugleweed has no known severe side effects. Like any other herbal supplement, there is the possibility of a severe allergic reaction or anaphylactic shock.

Symptoms of anaphylactic shock may include:

  • Trouble breathing or noisy breath sounds
  • Swelling of the tongue or throat
  • Constriction of the throat
  • Cardiac effects

 A person experiencing symptoms of anaphylactic shock should seek immediate emergency medical care.

Precautions

Though there are no known side effects of bugleweed, it should still be taken by people with caution, including those able to become pregnant or who are nursing and those who have hypothyroidism, diabetes, and other endocrine disorders. People taking oral contraceptives and fertility drugs should also use caution while using bugleweed.

Bugleweed dried herb
Verywell / Anastasia Tretiak

Dosage: How Much Bugleweed Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage is appropriate for your individual needs.

Thyroid: One clinical study with 62 participants observed the effects of bugleweed on thyroid labs. Participants were given a dosage of 20 milligrams daily for 30 days in this study.

Even so, a standard dosage for bugleweed is lacking.

What Happens if I Take Too Much Bugleweed?

Bugleweed was shown to be safe in a clinical study. There are no indications for upper dosing limits for bugleweed. This is because of the lack of clinical studies on the dosing of bugleweed in humans.

When considering using bugleweed, it is best to consult with a healthcare provider about what dose would be best for you.

Interactions

Bugleweed may not be safe when breastfeeding. Bugleweed extracts have had hormonal effects on humans and animals. These effects could disrupt the normal hormones required for a safe pregnancy or adequate milk production when nursing. No clinical studies indicate that using bugleweed while breastfeeding is safe or effective for an infant.

Bugleweed may decrease thyroid hormone levels. Because of this, it is not recommended that those with hypothyroidism use bugleweed. For the same reasons, taking bugleweed with hyperthyroidism medications is not recommended.

Other supplements such as selenium, lemon balm (Melissa officinalis), and zinc may affect the symptoms of thyroid diseases. It is recommended to avoid taking these along with bugleweed.

In clinical studies, vitamin D3 had effects on symptoms of thyroid disease as well, but the clinical research exploring these effects looked at people who were deficient in vitamin D. Further studies are needed to confirm this effect in people with normal or elevated vitamin D levels.

Bugleweed may have an impact on contraceptives and fertility medications. Taking bugleweed with contraceptives or fertility drugs should be avoided.

It is essential to carefully read a supplement's nutrition facts and ingredients panel to know which ingredients are present and how much of each is included. Review the supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

How to Store Bugleweed

Follow the manufacturer's recommendations on the packaging for both storage and disposal.

Similar Supplements

Some supplements that have impacted thyroid lab results include:

  • Selenium
  • Vitamin D3
  • Lemon balm (Melissa officinalis)
  • Zinc

Several clinical studies exist on the effects of vitamin D on hyperthyroidism. The results are inconclusive.

It would be best to consult with a healthcare professional when considering using bugleweed along with any of the supplements listed.

Frequently Asked Questions

  • Does bugleweed decrease the bulging eye symptom of Graves' disease?

    There is no clinical evidence that bugleweed decreases eye bulging of those with Graves' disease. Few clinical studies exist concerning its effect on hyperthyroidism in humans.

  • Are there dermatological effects of bugleweed?

    The juice of the bugleweed contains a black dye. When applied to the skin it can stain the skin, giving it a tan look.

Sources of Bugleweed and What to Look For

Bugleweed is taken as a supplement. It is not used as a food or in food products. It is available in dried form to be steeped into a tea and also in liquid forms in tinctures and oils.

Purchase wild-harvested bugleweed, certified by a third party, to ensure the strength and quality of the product. 

Bugleweed Supplements

Both dried and liquid forms are available over the counter (OTC, without a prescription) and online.

Use caution when purchasing bugleweed on the Internet. Herbs and other natural supplements are not regulated by the Food and Drug Administration (FDA) or any other governing agency. Manufacturers are not bound to the same level of quality standards as for prescription or over-the-counter medications.

Summary

Bugleweed has many traditional uses. These uses have not yet been backed by studies in humans.

If you are considering using bugleweed, consult with your healthcare provider first, particularly if you have a medical condition or are taking prescription or over-the-counter medications or other supplements.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Dawn Sheldon, RN
Dawn Sheldon, RN, is a registered nurse and health writer. She is passionate about sharing her knowledge and empowering others.