Bugleweed (Lycopus americanus) is a plant. The parts of the plant that grow above the ground are sometimes used as medicine.

People use bugleweed for overactive thyroid (hyperthyroidism), premenstrual syndrome (PMS), insomnia, and other conditions, but there is no good scientific evidence to support these uses.

Do not confuse bugleweed with white horehound, black horehound, or veronica. These are not the same.
When taken by mouth: There isn't enough reliable information to know if bugleweed is safe or what the side effects might be.

Special Precautions & Warnings:

Pregnancy: It's likely unsafe to take bugleweed by mouth during pregnancy because it might affect hormones.

Breast-feeding: It's possibly unsafe to take bugleweed by mouth while breast-feeding. It might affect milk production.

Thyroid disorders: Don't use bugleweed if you have a thyroid disorder or are receiving thyroid treatments.


There is interest in using bugleweed for a number of purposes, but there isn't enough reliable information to say whether it might be helpful.
Likely effective Effectiveness definitions
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Dosing & administration

There isn't enough reliable information to know what an appropriate dose of bugleweed might be. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult a healthcare professional before using.

Interactions with pharmaceuticals

Thyroid hormone

Interaction Rating=Moderate Be cautious with this combination.

Taking bugleweed might change the way that thyroid hormone pills work. Don't take bugleweed if you take thyroid pills.

Interactions with herbs & supplements

Herbs that decrease production of thyroid hormones: Bugleweed might affect the body's production of thyroid hormone. Taking it with other supplements with similar effects might alter thyroid function too much and cause side effects. Examples of supplements with this effect include lemon balm and tiratricol.

Interactions with foods

There are no known interactions with foods.
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This monograph was last reviewed on 18/09/2023 10:00:00 and last updated on 25/09/2022 23:36:23. Monographs are reviewed and/or updated multiple times per month and at least once per year.
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