Can Valerian Lower Blood Pressure?

Valerian is a common herb found in over-the-counter dietary supplements. Its roots, stems, and leaves are incorporated into teas, tinctures, capsules, or pills, according to the National Institutes of Health (NIH). It’s commonly marketed as a remedy for insomnia, anxiety, muscle spasms, and symptoms related to menopause, notes Memorial Sloan Kettering Cancer Center (MSKCC).

Limited research on animals has shown that valerian can lower blood pressure. However, there hasn’t been significant research on valerian’s effects on blood pressure in humans, or as a treatment for hypertension. As always, you should talk to your doctor before attempting to self-medicate any condition with valerian.

It’s not clear what specific chemical component of valerian works to produce its effect, notes the NIH. It’s believed that any potential medicinal properties come from multiple chemicals, either acting independently or working together.

Valerian has a long history as a medicinal plant, dating as far back as ancient Greece and Rome, when it was used to treat insomnia. Valerian has been studied as a treatment for conditions as varied as gastrointestinal spasms, epilepsy, and attention deficit hyperactivity disorder (ADHD), but there’s no conclusive evidence of its usefulness in those conditions.

Valerian is sold in the United States as a dietary supplement, not as a drug. According to the U.S. Food & Drug Administration (FDA), this means the agency doesn’t evaluate and approve valerian products for safety or effectiveness before they’re sold. To make sure the product you’re buying contains the ingredients listed at the strength the manufacturer claims, look for products that have been tested by independent third parties, such as ConsumerLab.com, the National Sanitation Foundation (NSF), or U.S. Pharmacopeia (USP), advises the NIH.

According to MSKCC, some research suggests that chemical compounds in valerian bind to receptors of chemical messengers in the nervous system, or neurotransmitters, that are involved in sleep-wake cycles and anxiety. Other research, done on lab-grown cells or animals, has shown that antianxiety effects may be due to the chemical valerenic acid, which indirectly increases the concentration of the relaxing neurotransmitter gamma-aminobutyric acid (GABA) and decreases central nervous system activity, which is similar to how antianxiety medications in the benzodiazepine class work.

Some research has also shown that valerian’s potential blood pressure–lowering effect may be connected to its ability to help relax and open blood vessels.

No significant research has addressed the question of using valerian in the treatment of high blood pressure, or hypertension. There is some older research that measures blood pressure in people without hypertension, including one small study in which 18 participants took valerian supplements for seven days. It found that supplements significantly decreased systolic blood pressure but not diastolic blood pressure. Hypertension treatments are used to reduce both blood pressure values measured — systolic and diastolic — which valerian may not be able to do.

Because there isn’t enough research on humans or hypertension specifically, it’s not known what doses are safe and effective for treatment of hypertension, or if it’s safe and effective for hypertension in the first place. It’s also not known whether valerian can be used in the long term without adverse effects. Talk to your doctor about whether using valerian to treat hypertension is appropriate for you.

According to the NIH, few adverse effects were reported among research participants — headaches, dizziness, itchiness, and gastrointestinal issues were most common. MSKCC notes that complaints of daytime sleepiness, sweating, and heart palpitations have also been reported, as well as a withdrawal effect when stopping valerian, similar to when people stop taking antianxiety medications in the benzodiazepine class.

If you’re pregnant or nursing, you should avoid taking valerian, since its effects on fetuses and infants are unknown. People with liver and pancreatic disease should also steer clear of the herb. Operating dangerous machinery is similarly not advised when taking it. Valerian may increase the effects of sedatives and alcohol, so they shouldn’t be mixed. It should also be discontinued a week before surgery, as valerian may interact with anesthesia.