In test tube studies, yarrow’s active ingredients have been shown to work as antibiotics, antioxidants, anti-proliferatives (slowing cell growth), and more. These properties make yarrow a supplement of interest for almost everything from multiple sclerosis to cancer. Here’s what you need to know about yarrow before adding it to your medicine cabinet.
Uses of Yarrow
Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.
Although yarrow has been used traditionally in many cultures for many health conditions, only weak evidence exists to confirm the plant’s benefits. Most scientific research has been performed on animals or isolated cells in a lab. This means research is in its early stages. The findings must be replicated in more extensive and in-depth studies before the yarrow’s complete safety and benefit profile is established.
Here are some uses that studies in humans have explored:
Wound Healing
Yarrow leaves, or juice made from its leaves, have historically been applied directly to wounds to aid healing. There isn’t much compelling research to support this use.
A randomized controlled trial of 140 women showed a positive effect of yarrow ointments on the healing of episiotomies (a small incision in the perineum that healthcare providers sometimes make during childbirth).
Yarrow has also been studied for its effects on cracked nipples due to breastfeeding. A study of 150 participants showed that yarrow helped, but not more than applying breastmilk or honey to the nipples.
Skin Inflammation
Yarrow is thought to act as an anti-inflammatory and antioxidant when applied to the skin. A randomized controlled trial in volunteers demonstrated that yarrow helped restore artificially irritated skin. Further study is needed.
Dysmenorrhea
There is sparse data supporting yarrow’s use in alleviating pain during menstrual cycles, although people use it anecdotally for this. In one randomized controlled trial yarrow tea was shown to decrease the pain of people experiencing dysmenorrhea (painful menstrual cycles). Only 91 students were involved in the study and all were adolescents, so the effects could differ for other age groups.
Multiple Sclerosis
A randomized controlled trial showed yearly relapses (acute attacks) decreased in people with multiple sclerosis who were given either 250 mg or 500 mg of yarrow daily for one year. In this study yarrow was given as add-on therapy, meaning it was an addition to maintenance medicines. People with multiple sclerosis who took yarrow along with their regular treatments showed improvements on cognitive tests. Further study is needed.
Irritable Bowel Syndrome
Yarrow is sometimes used in treating irritable bowel syndrome (IBS) because of its antispasmodic activity. This means it may decrease muscle spasms in the intestines and ease stomach cramping. So far, there is no substantial evidence to support this historical use.
A randomized controlled trial of 60 people with IBS showed that a mixture of yarrow and two other herbal supplements decreased symptoms. However, the result was not statistically significant. That means that the same thing could have happened simply by chance. Also, it is impossible to predict the effect of yarrow alone for IBS since it was given as a combination product in this trial.
Other Studied Conditions
While data in humans are lacking, some people also use yarrow for:
Bacterial infections Respiratory viruses like COVID-19 Regulating blood sugar in type 2 diabetes Anxiety Protecting the liver and gallbladder Cancer Chemotherapy-related toxicities Cosmetic uses
It’s important to highlight that most of these studies were done on mouse models or using cells in a lab. We don’t know if the effects will be the same in humans. Further research in humans is needed before we can give yarrow the green light for any of these uses.
What Are the Side Effects of Yarrow?
While a “natural” product, keep in mind that even natural substances can have side effects and drug interactions. Think of these products as you would pharmaceutical drugs. Most of the available safety data come from studies in mice, so we don’t know too much about side effects in humans yet.
Common Side Effects
Yarrow is generally considered safe to use medicinally, but possible side effects may include:
Skin irritation when used topically. Sesquiterpenes in yarrow may cause contact dermatitis or skin rash. Increased urination. Yarrow had a diuretic effect in a rat model.
However, some groups of people may face additional risks from taking yarrow supplements.
Severe Side Effects
In one case report, a woman who consumed five cups a day of yarrow tea for one week went to the emergency room complaining of blurry vision, dry mouth, fatigue, and heart palpitations. These symptoms are consistent with anticholinergic toxicity, which can also include hallucinations, seizures, or coma in severe cases.
Importantly, there is no data to confirm that yarrow has anticholinergic effects. However, if you experience these or any other symptoms after taking this supplement, head to the emergency room to be safe.
Precautions
Some groups of people may face additional risks from taking yarrow supplements:
Pregnancy and Breastfeeding
Yarrow is not recommended for use during pregnancy or breastfeeding. An ingredient of yarrow called thujone could put you at risk for miscarriage if you take it while pregnant.
So far, we don’t know enough about the risk of yarrow during breastfeeding, so it’s safest to avoid using it until after your baby is weaned.
Infants and Children
Because of a lack of studies on safety or efficacy in children, use in this population is not recommended.
Allergies
If you’re allergic to plants that are members of the Asteraceae/Compositae family, you may also be allergic to yarrow. Other plants in the family include:
ChrysanthemumsDaisiesMarigoldsRagweed
If you have plant allergies but don’t know for sure about this particular group of plants, talk to your healthcare provider before taking yarrow.
Increased Bleeding Risk
The research on this is quite limited, but a study in rabbits showed decreased blood clotting time when they were given achilleine, an ingredient of yarrow. Because yarrow could theoretically slow blood clotting, you should discuss its use with your healthcare provider before any surgeries. It may need to be stopped prior to the procedure.
Dosage: How Much Yarrow Should I Take?
There’s no established standard dosing for yarrow, although daily dosing of up to 500 mg has been used safely for up to a year in one human study.
Always follow instructions on product labels and include your healthcare provider and pharmacist in your decisions. Look for yarrow supplementation certified by a third party if purchasing it in a store.
What Happens If I Take Too Much Yarrow?
There is insufficient data to predict the effects of taking too much yarrow. If you feel you’ve ingested too much yarrow, seek immediate guidance from a healthcare provider.
Interactions
There is very little evidence about yarrow’s interactions with prescription medications or other herbal supplements. Yarrow may have a negative interaction with the following remedies, but these are primarily theoretical:
Anti-inflammatories, anticoagulants, and antiplatelet drugs: These slow blood clotting; bleeding risk might be increased by taking yarrow. Sedatives: If taken with yarrow may cause excessive drowsiness. Lithium: Yarrow may decrease your body’s ability to get rid of lithium, increasing the risk of lithium build-up and severe side effects.
Herbal supplements containing thujone: Thujone is an ingredient of yarrow, and at high doses, it is toxic to the brain and may cause seizures.
It is essential to carefully read a supplement’s ingredient list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.
How to Store Yarrow
Most commercially available yarrow products can be safely stored at room temperature. Always follow package directions regarding storage and expiration dates.
The plant leaves may be dried, though it is unknown how long to keep them on your shelf. Some suggest throwing it out when its aroma begins to fade, as it may become less potent.
Similar Supplements
Many supplements are similarly touted for wound healing, including:
Aloe Chamomile Echinacea Rosemary St. John’s wort
Like yarrow, these herbs have been used extensively in traditional medicine and are available in several dosage forms.
Sage, cedar leaf, and wormwood are some other herbs that contain thujone. Like yarrow, these should not be used in pregnancy. Check with your healthcare provider before taking yarrow if you are also taking any of these supplements. At high doses, thujone may cause seizures, so the recommended maximum daily amount is three to seven milligrams (mg).
Sources of Yarrow & What To Look For
Sources of yarrow are the plant itself and supplements made from it.
Food Sources of Yarrow
The yarrow root may be ground up to make a spice. Flowers and leaves of the plant are used by some people as ingredients in soups or salads. Yarrow is not a common ingredient in commercially available foods in the United States.
Yarrow Supplements
Yarrow is commercially available in various dosage forms, including herbal teas, capsules, essential oil, ointments, and tinctures.
Essential oil or ointment applied to the skin may be preferable because of decreased systemic (body-wide) side effects.
Tinctures are highly concentrated extracts made by soaking the plant in alcohol. Doses are taken by mouth using a dropper. Because of the alcohol content (often 25-60%), this form may not be recommended in children or during pregnancy. Check with your child’s pediatrician or your OB/GYN before use.
Summary
Yarrow has a long history of use in folk medicine and has theoretical benefits for various health conditions. There is only weak evidence to support its use in humans, however. More robust human trials are needed before yarrow can be considered safe or effective. As with all supplements, discuss yarrow with your healthcare provider before adding it to your daily routine.
