Valerian

Valerian (Valeriana officinalis) has been used for centuries as a medicinal herb, particularly for relaxation and restful sleep. Native to Europe and parts of Asia, this perennial flowering plant is best known for its distinctive roots, which have traditionally been brewed into tea or prepared as tinctures, extracts, and other herbal remedies.

Today, valerian root remains a popular ingredient in nighttime teas and herbal supplements. Many people reach for it when they’re looking for a simple way to wind down at the end of the day. Researchers have also studied several compounds found in valerian root—including valerenic acids—to better understand how the herb may influence sleep and the nervous system.

In this guide, we’ll explore the potential benefits of valerian root, what current research says about its traditional uses, how to make valerian tea, common ways to use it, dosage and safety considerations, possible side effects, and how to grow, harvest, and store valerian at home.

Scientific Name: VALERIANA OFFICINALIS

What Is Valerian?

Valerian (Valeriana officinalis) is a hardy perennial herb in the honeysuckle family (Caprifoliaceae). Native to Europe and parts of Asia, it has also become naturalized in North America. The plant prefers moist growing conditions and can often be found in meadows, along riverbanks, at woodland edges, and in gardens. Mature valerian can reach about 3–5 feet (90–150 cm) tall and produces clusters of small white to pale pink flowers in summer.

Although valerian is an attractive flowering plant, the root is the part most commonly used in herbal preparations. After harvesting, valerian roots and rhizomes are typically cleaned and dried before being used in teas, capsules, tinctures, extracts, and powders.

Valerian root is especially well known for its strong, distinctive smell. Dried root develops an earthy, musky odor that is sometimes compared to old cheese or damp soil. It may not be everyone’s favorite aroma, but it is a normal characteristic of the herb rather than a sign that the root has spoiled.

Interestingly, valerian can also attract cats. Some cats respond strongly to the scent of the root in a way that resembles their reaction to catnip, which has even led to valerian being included in some herbal cat toys.

A Brief History of Valerian

Valerian has a long history in European herbal medicine, with references to the plant dating back to ancient Greece and Rome. Early physicians and herbalists described valerian for a variety of purposes, and its association with rest and relaxation developed over centuries of traditional use.

During the Middle Ages, valerian continued to appear in European herbal preparations. The root was commonly collected, dried, and incorporated into remedies used for nervousness, restlessness, and difficulty sleeping.

By the 18th and 19th centuries, valerian was appearing regularly in European and North American botanical and medical texts. Its reputation as an herb associated with rest and nervous tension has continued into modern herbal practice.

What’s Inside Valerian Root?

Valerian’s roots and rhizomes contain a mixture of naturally occurring compounds, including valerenic acids, iridoids, volatile oils, and several other phytochemicals. Valerenic acid has attracted particular research interest because of its possible interaction with pathways involved in nervous-system activity.

The amount and composition of these compounds can vary according to the plant, growing conditions, harvest, processing, and type of extract.

How Is Valerian Used Today?

Valerian is now sold in several forms, so you don’t necessarily have to brew the strong-smelling root yourself. Common options include:

• Herbal tea made from dried valerian root.
• Capsules and tablets containing powdered root or valerian extract.
• Tinctures and liquid extracts that provide a concentrated preparation.
• Powdered root for use in homemade herbal preparations.
• Herbal blends that combine valerian with herbs such as chamomile, lemon balm, passionflower, or lavender.

These are just a few of the ways medicinal herbs are prepared. You can also explore our guide to natural herbs for everyday ailments for a closer look at other commonly used herbs.

Tea offers a more traditional way to use the herb, while capsules and extracts can be more convenient for people who dislike valerian’s strong aroma and flavor.

Valerian’s long history doesn’t necessarily mean that every traditional claim about it has been scientifically confirmed. Modern research has focused primarily on its possible effects on sleep and relaxation, with results varying among studies. Much of today’s research has therefore focused on a straightforward question: does valerian actually live up to its traditional reputation?

Potential Health Benefits of Valerian Root

Valerian root is best known for its traditional use as a calming herb and natural sleep aid. Modern research has focused largely on sleep quality, relaxation, and the way certain valerian compounds may interact with the nervous system. However, study results have been mixed, and valerian should not be viewed as a proven treatment for insomnia, anxiety, or other medical conditions.

May Support Sleep Quality

Sleep is the main reason many people turn to valerian root. Some clinical studies have reported improvements in perceived sleep quality or the amount of time it takes to fall asleep, while others have found little or no meaningful benefit.

One reason for the inconsistent findings may be differences in the valerian preparations used. Studies have tested different extracts, doses, treatment periods, and groups of participants, making direct comparisons difficult.

Overall, valerian may help some people with occasional sleep difficulties, but current evidence does not establish it as a reliable treatment for chronic insomnia.

May Promote Relaxation

Valerian has traditionally been used during periods of nervousness and restlessness. Researchers have investigated whether compounds in the root may influence signaling involving gamma-aminobutyric acid (GABA), an important neurotransmitter involved in regulating activity in the nervous system.

Valerenic acid is of particular interest because laboratory research suggests it may interact with GABA-related pathways. However, laboratory findings do not automatically translate into a proven benefit in people.

For someone experiencing persistent anxiety, panic attacks, or other significant symptoms, valerian should not replace evaluation and treatment from a healthcare professional.

This traditional calming use is also why valerian is sometimes included in evening formulas intended for people who have trouble winding down.

May Have a Role in a Relaxing Bedtime Routine

There’s also something to be said for the ritual itself. Making a warm, caffeine-free tea and sitting down without a phone or computer can become a useful signal that the day is winding down.

Valerian is sometimes combined with other herbs traditionally associated with relaxation, including chamomile, lemon balm, passionflower, hops, and lavender.

A healthy nighttime routine can also include dimming the lights, reducing screen use before bed, keeping a consistent sleep schedule, and limiting caffeine later in the day.

What Does the Research Say Overall?

Valerian is interesting because its traditional reputation is stronger than the certainty of the clinical evidence currently available.

Some studies have produced encouraging results, particularly for subjective sleep quality, while systematic reviews have found considerable differences between studies and insufficient evidence to draw firm conclusions about valerian’s effectiveness for insomnia.

That doesn’t mean valerian has no value. It means claims about the herb should remain realistic. Research is continuing, and factors such as the type of extract, preparation method, dose, and duration of use may influence results.

For now, valerian is best viewed as a traditional herbal option that may support relaxation or sleep for some people, rather than a proven treatment for a sleep or anxiety disorder.

Safety note: Valerian can cause drowsiness and may interact with alcohol, sedatives, sleep medications, and other substances that affect the central nervous system. If you take medications, are pregnant or breastfeeding, have a medical condition, or experience persistent sleep problems, speak with a qualified healthcare professional before using valerian supplements.

Active Compounds in Valerian Root

Valerian root contains a complex mixture of naturally occurring compounds rather than one single ingredient responsible for all of its effects. Researchers have studied several of these constituents to understand why valerian has such a long history of use for relaxation and sleep.

Valerenic Acids

Valerenic acid and related compounds are among the most studied constituents of Valeriana officinalis. They are found in the plant’s underground parts and are often used as chemical markers when standardizing commercial valerian extracts.

Laboratory research suggests that valerenic acid may influence signaling involving gamma-aminobutyric acid (GABA), a neurotransmitter that helps regulate activity within the nervous system. This is one proposed explanation for valerian’s traditional association with relaxation.

However, the way isolated compounds behave in laboratory studies does not necessarily predict how a complete valerian preparation will affect people.

Valepotriates

Valepotriates are a group of naturally occurring iridoid compounds found in valerian. They have been investigated for several types of biological activity, but they are relatively unstable and can break down during drying, storage, and processing.

As a result, the amount present in a finished valerian product may differ considerably from the amount found in freshly harvested plant material.

Essential Oils

Valerian root also contains volatile oils that contribute to its characteristic aroma. Its smell becomes especially noticeable after the root is harvested and dried.

The exact composition of these oils can vary according to growing conditions, plant material, processing, and storage.

Other Plant Compounds

Valerian contains numerous additional phytochemicals, including certain flavonoids, lignans, organic acids, and other naturally occurring constituents.

Researchers continue to investigate whether individual compounds or combinations of compounds contribute to valerian’s biological effects. At present, it would be overly simplistic to attribute all of the herb’s traditional properties to one chemical.

Why Valerian Products Can Differ

Two valerian supplements sitting next to each other on a store shelf aren’t necessarily identical. Their chemical composition can be influenced by:

• The valerian species and plant material used.
• Where and how the plant was grown.
• When the roots and rhizomes were harvested.
• Drying and storage conditions.
• The extraction method.
• The concentration of the finished extract.

Some supplements are standardized to specific amounts of valerenic acids, while others contain powdered whole root or non-standardized extracts.

This variation is one reason research results—and people’s experiences with valerian products—can differ.

When choosing a supplement, check that the label identifies the botanical as Valeriana officinalis and clearly states the plant part and amount used. Products from manufacturers that provide independent quality testing can offer additional reassurance about identity, purity, and consistency.

How to Use Valerian Root

Valerian root is available as tea, capsules, tablets, tinctures, liquid extracts, and powders. The best form usually comes down to convenience and personal preference—especially whether you enjoy valerian’s strong earthy aroma.

Valerian Root Tea

Tea is one of the simplest traditional ways to prepare valerian root. Unlike herbal teas made from delicate leaves and flowers, valerian tea uses the dried underground parts of the plant.

For a simple cup of valerian tea:

1. Place about 1 teaspoon of dried valerian root in a tea infuser or cup.
2. Add approximately 8 ounces (240 ml) of hot water.
3. Cover the cup and allow the root to steep for about 10–15 minutes.
4. Strain the tea before drinking.
5. Add a little honey or another herb if you find the flavor too strong.

Valerian has a noticeably earthy, somewhat bitter taste and an aroma that isn’t for everyone. Combining it with chamomile, lemon balm, peppermint, or lavender can make the tea more enjoyable.

If you’re using a packaged valerian tea, follow the preparation directions provided by the manufacturer because the amount of herb can vary.

Capsules and Tablets

Capsules and tablets are convenient alternatives for anyone who doesn’t enjoy the smell or taste of valerian tea.

Products may contain powdered valerian root or a concentrated extract, so two capsules from different brands can contain very different preparations. Check the label rather than assuming that all valerian supplements are equivalent.

Tinctures and Liquid Extracts

Valerian is also available as tinctures and other liquid extracts. These concentrated products are generally taken in small measured amounts according to the manufacturer’s instructions.

Because extraction methods and concentrations vary, there isn’t a universal number of drops that applies to every product. Follow the specific directions on the label.

Valerian Root Powder

Dried valerian can also be ground into a powder. Its strong flavor makes it less appealing in foods or smoothies, but the powder can be measured into capsules or incorporated into other homemade herbal preparations.

Store valerian powder tightly sealed and protected from heat, light, and moisture.

Valerian in Herbal Blends

Valerian frequently appears in nighttime teas and supplements alongside other herbs traditionally associated with relaxation. If you enjoy comparing traditional herbal preparations, our guide to herbal medicine and how it is used provides a broader introduction to common herbal practices. Common combinations include:

• Chamomile
• Lemon balm
• Passionflower
• Hops
• Lavender

A combination isn’t automatically more effective or safer simply because it contains several herbs. Each ingredient has its own potential effects, precautions, and medication interactions, so check the complete ingredient list before using a multi-herb supplement.

When Is Valerian Usually Taken?

Because valerian is primarily associated with relaxation and sleep, commercial products are commonly intended for evening use. The appropriate timing depends on the preparation and its concentration, so follow the directions provided with the specific product you’re using.

Until you know how valerian affects you, avoid driving, operating machinery, or performing activities that require full alertness after taking it.

Choosing a Valerian Product

Supplement quality can vary considerably. When comparing valerian products, look for a label that clearly provides:

• The botanical name Valeriana officinalis.
• The plant part used, usually root and/or rhizome.
• The amount per serving.
• Whether the product contains powdered root or an extract.
• Standardization information, if applicable.
• A complete list of additional ingredients.

Independent testing from a recognized third-party organization can provide additional assurance that a supplement contains what its label claims and has been screened for certain contaminants.

Whichever form you choose, the amount matters—particularly with concentrated extracts.

Valerian Dosage, Safety, and Possible Side Effects

Valerian is widely available without a prescription, but that doesn’t mean every product should be used in the same amount. Capsules, teas, tinctures, powders, and standardized extracts can differ substantially in strength and composition.

There is no single valerian dosage that is appropriate for everyone. The amount used in clinical research has varied depending on the preparation being studied, and supplement labels may recommend different serving sizes.

How Much Valerian Should You Take?

For sleep-related research, studies have often used valerian extracts providing approximately 300–600 mg, typically taken before bedtime. European herbal guidance also distinguishes between different valerian preparations, which is another reason dosage should be based on the specific product rather than valerian root in general. However, this range should be viewed as an example of amounts studied—not a universal dosage recommendation.

Dried-root teas and liquid preparations cannot be directly compared with extract capsules on a milligram-for-milligram basis.

For practical use, it makes sense to:

• Follow the serving directions on your specific product.
• Avoid exceeding the manufacturer’s recommended amount.
• Start cautiously if you have never used valerian before.
• Ask a healthcare professional or pharmacist for guidance if you take medications or have a medical condition.

More valerian does not necessarily mean a stronger or better effect.

Possible Side Effects of Valerian

Valerian appears to be well tolerated by many adults when used for short periods, but side effects can occur.

Reported effects include:

• Headache
• Dizziness
• Digestive discomfort
• Drowsiness
• Mental sluggishness
• Vivid dreams

Some people may also feel sleepy or less alert after taking valerian. Until you know how your body responds, avoid driving or operating machinery after using it.

Can Valerian Interact With Medications?

Valerian may have additive effects when combined with substances that cause sedation or affect the central nervous system.

Particular caution is appropriate with:

• Prescription sleep medications
• Sedatives and tranquilizers
• Some anti-anxiety medications
• Other products that cause drowsiness
• Alcohol

If you take prescription or over-the-counter medications, check with a healthcare professional or pharmacist before adding a valerian supplement.

Who Should Avoid Valerian?

Safety information is limited for certain groups. Valerian generally should not be used without professional medical guidance by people who:

• Are pregnant or breastfeeding.
• Are giving valerian to a young child.
• Take medications that cause sedation.
• Have a medical condition that could be affected by supplement use.
• Are preparing for surgery or a medical procedure requiring anesthesia or sedation.

If you have an upcoming procedure, tell your healthcare team about all supplements and herbs you use, including valerian.

Can You Use Valerian Long Term?

Most clinical research on valerian has examined relatively short periods of use, so there is less information about taking it continuously for many months or years.

If you find yourself relying on valerian every night or your sleep problems continue, it’s worth discussing the situation with a healthcare professional rather than continually increasing the amount or adding additional sleep products.

Persistent insomnia can have many causes, including stress, medications, sleep disorders, and underlying health conditions.

What About Long-Term or High-Dose Use?

Research on prolonged valerian use is limited. Rare reports have described symptoms after abruptly stopping very large amounts following extended use, but this isn’t well characterized.

If you’ve been taking unusually high amounts or using valerian regularly for a long time, discuss changes with a healthcare professional.

Using Valerian Responsibly

A few basic precautions can make herbal supplement use safer:

• Buy products from reputable manufacturers.
• Read the complete ingredient and warning labels.
• Don’t combine several sleep supplements without checking their ingredients.
• Avoid mixing valerian with alcohol or sedating drugs unless a healthcare professional has advised you otherwise.
• Keep supplements out of reach of children.
• Stop using the product and seek medical advice if you experience a serious or unexpected reaction.

Valerian’s long history of traditional use doesn’t eliminate the possibility of side effects or interactions. Treat it as an active herbal product rather than simply another type of tea—particularly when using concentrated extracts or supplements.

How to Grow Valerian

Most people encounter valerian as dried root, tea, or a supplement, but Valeriana officinalis is also an attractive perennial you can grow at home. The plant produces tall stems topped with clusters of small white to pale pink flowers, while the roots and rhizomes beneath the soil are the parts traditionally harvested for herbal preparations.

Once established, valerian is relatively easy to maintain, although it grows best when given plenty of moisture and enough room to develop.

Where to Plant Valerian

Choose a location with full sun to partial shade. In cooler climates, valerian generally handles full sun well. In regions with hot summers, some afternoon shade can help prevent the soil from drying too quickly.

Because mature plants can grow several feet tall, place valerian where it won’t shade smaller herbs growing nearby.

Best Soil for Valerian

Valerian prefers fertile soil that holds some moisture without remaining waterlogged.

For good growth, aim for soil that is:

• Rich in organic matter.
• Moist but well drained.
• Loose enough for healthy root development.
• Slightly acidic to neutral.

Adding compost before planting can improve both soil structure and fertility.

Growing Valerian From Seed

Valerian can be started from seed in spring. The seeds are small and should be planted shallowly rather than buried deeply.

To get started:

1. Prepare a fine, moist seed-starting mix or garden bed.
2. Scatter or place the seeds on the surface.
3. Press them gently against the soil.
4. Cover them only very lightly, if at all.
5. Keep the surface consistently moist while the seeds germinate.

Valerian seed can lose viability relatively quickly, so fresher seed generally gives you a better chance of successful germination.

Once seedlings are large enough to handle, thin or transplant them so mature plants have roughly 18–24 inches (45–60 cm) of space.

Watering Valerian

Valerian naturally favors moist environments, so don’t allow newly planted seedlings to dry out completely.

Established plants also appreciate consistent moisture, particularly during hot or dry weather. A layer of organic mulch around the plants can slow evaporation and reduce competition from weeds.

At the same time, avoid constantly saturated soil. Good drainage helps protect the underground roots and rhizomes from rot.

Does Valerian Need Fertilizer?

Valerian generally doesn’t require heavy feeding in reasonably fertile garden soil.

Adding compost when planting and top-dressing established plants with compost can usually provide adequate nutrients. Excessive nitrogen isn’t necessary and may encourage abundant leafy growth when your main interest is developing healthy roots.

Flowers and Self-Seeding

Valerian produces clusters of small flowers during summer. If the flower heads are allowed to mature, the plant can self-seed and gradually spread beyond its original location.

This can be useful if you’d like a naturalized patch of valerian, but gardeners who want to keep it contained should remove spent flower heads before the seeds mature.

Growing Valerian in Containers

Valerian can be grown in containers, although its height and root system mean a small herb pot isn’t ideal.

Choose a large, deep container with drainage holes and fill it with a fertile, well-draining potting mix. Container-grown valerian may need watering more frequently than plants growing directly in the garden.

A heavier pot can also help keep tall plants stable during windy weather.

When to Harvest Valerian Root

Valerian roots and rhizomes are commonly harvested when the plant’s above-ground growth begins dying back, usually in the fall. Established plants provide a larger root system than very young seedlings.

To harvest:

1. Loosen the soil around the plant with a garden fork or spade.
2. Carefully lift the root system without unnecessarily cutting it apart.
3. Shake away loose soil.
4. Separate the roots you intend to use.
5. Wash them thoroughly to remove remaining soil.

The characteristic valerian smell often becomes considerably stronger as the roots dry.

How to Dry Valerian Root

After washing, cut thick roots into smaller pieces so they dry more evenly.

Spread them in a thin layer in a dry, well-ventilated area away from direct sunlight, or use a food dehydrator at an appropriate low temperature. The roots need to be completely dry before storage; remaining moisture can encourage mold and spoilage.

Once fully dried, place the root in a tightly sealed container and store it somewhere cool, dark, and dry. Label the container with the herb and harvest date so you can keep track of your homegrown supply.

Growing valerian gives you an opportunity to see the entire life cycle of an herb that most people encounter only as a dried root or supplement. Just remember that correctly identifying, harvesting, drying, and storing medicinal plants is important before using anything you’ve grown in homemade herbal preparations.

Frequently Asked Questions About Valerian Root

Is valerian root good for sleep?

Valerian root has a long history of traditional use for sleep and relaxation. Some studies suggest it may improve certain aspects of sleep for some people, while others have found little or no benefit. Overall, the evidence remains mixed, so valerian should not be considered a proven treatment for insomnia.

How long does valerian take to work?

There isn’t a single established time that applies to everyone. Valerian products also differ considerably in their preparation and concentration. Commercial sleep products containing valerian are often intended for use before bedtime, so follow the directions provided with the specific product.

Can you drink valerian tea every day?

Valerian tea is commonly used as an evening herbal drink, but research on continuous long-term use is limited. If you plan to use valerian regularly for an extended period—especially if you take medications—discuss it with a healthcare professional.

What does valerian tea taste like?

Valerian root has a strong earthy and somewhat bitter flavor accompanied by a distinctive musky aroma. Some people enjoy it on its own, while others blend it with better-tasting herbs such as chamomile, lemon balm, lavender, or peppermint.

Does valerian root contain caffeine?

No. Valerian itself is naturally caffeine-free. However, if you purchase a commercial herbal blend, check the complete ingredient list to make sure it doesn’t contain tea leaves or another source of caffeine.

Is valerian root safe?

Valerian appears to be well tolerated by many adults during short-term use, but it can cause side effects such as headache, dizziness, digestive discomfort, or drowsiness. Safety during pregnancy, breastfeeding, childhood, and prolonged use has not been adequately established.

What should you avoid combining with valerian?

Combining valerian with sleep medications or other sedating substances may increase drowsiness and other central nervous system effects. Talk with your healthcare provider or pharmacist before combining valerian with prescription or over-the-counter sleep products.

Combining valerian with alcohol is generally discouraged because both can cause sedation and impair alertness. The combination may increase drowsiness or other unwanted effects.

Is valerian addictive?

Valerian is not generally regarded as addictive in the same way as certain prescription sedatives. However, information about very high doses and prolonged use is limited, and rare reports of symptoms following abrupt discontinuation have been described. Long-term or unusually high-dose use should be discussed with a healthcare professional.

Is valerian the same as chamomile?

No. Valerian and chamomile are different plants. Valerian preparations primarily use the roots and rhizomes of Valeriana officinalis, while chamomile tea is usually made from the flowers of German or Roman chamomile. Both have traditional associations with relaxation, but their plant compounds, flavors, and research evidence differ.

Can valerian and chamomile be used together?

Valerian and chamomile are commonly found together in commercial nighttime herbal blends. However, combining herbs can also combine their effects and precautions. Check the ingredients and directions of any multi-herb product, particularly if you take medications.

Can you grow valerian at home?

Yes. Valerian is a perennial that can be grown from seed or established plants. It generally prefers fertile, consistently moist but well-drained soil and full sun to partial shade. Because it can grow several feet tall and may self-seed, give it adequate space in the garden.

Why does valerian root smell so strong?

Valerian root naturally contains volatile compounds responsible for its characteristic earthy, musky odor. The smell often becomes more noticeable after harvesting and drying and does not by itself mean that properly dried valerian has spoiled.

Final Thoughts on Valerian Root

Valerian root has been part of traditional herbal medicine for centuries, and it remains one of the better-known herbs associated with relaxation and sleep. Today, you’ll find it in everything from bedtime teas to capsules, tinctures, and standardized extracts.

Research into valerian is still evolving. Some studies suggest potential benefits for sleep, while others have produced less convincing results. That’s an important distinction: valerian’s long history of traditional use shouldn’t be confused with proof that it can treat insomnia, anxiety, or other medical conditions.

For those interested in trying valerian, choosing a clearly labeled, high-quality product and following its directions is a sensible place to start. It’s equally important to consider possible medication interactions and its potential to cause drowsiness, particularly when using concentrated supplements.

And if you enjoy growing your own herbs, Valeriana officinalis offers something a little different. Its tall summer flowers make an attractive addition to the garden, while the roots provide an opportunity to learn how a traditional medicinal herb is grown, harvested, and prepared.

Ultimately, valerian is best approached for what it is: a traditional herb with a long history of use, ongoing scientific interest, and mixed evidence for its effects on sleep and relaxation.

References

1. National Institutes of Health, Office of Dietary Supplements. Valerian – Health Professional Fact Sheet. Covers Valeriana officinalis, preparations, sleep research, active constituents, safety, and interactions.
   NIH Office of Dietary Supplements – Valerian
2. European Medicines Agency (EMA). Valerianae radix – European Union Herbal Monograph. Official assessment of valerian root, including traditional/medicinal uses, preparations, dosing considerations, precautions, and safety.
   European Medicines Agency – Valerian Root
3. Bent S, Padula A, Moore D, Patterson M, Mehling W. Valerian for Sleep: A Systematic Review and Meta-Analysis. American Journal of Medicine. 2006;119(12):1005–1012. Review of 16 randomized controlled studies involving 1,093 participants; it also highlights substantial differences in study quality and valerian preparations.
   PubMed – Valerian for Sleep: Systematic Review and Meta-Analysis
4. Shinjyo N, Waddell G, Green J. Valerian Root in Treating Sleep Problems and Associated Disorders—A Systematic Review and Meta-Analysis. Journal of Evidence-Based Integrative Medicine. 2020;25. This later review included 60 studies and discusses why results across valerian studies have been inconsistent.
   PubMed – Valerian Root and Sleep Problems Review
5. Benke D, Barberis A, Kopp S, et al. GABA-A Receptors as In Vivo Substrate for the Anxiolytic Action of Valerenic Acid, a Major Constituent of Valerian Root Extracts. Neuropharmacology. 2009;56(1):174–181. Useful specifically for our discussion of valerenic acid and GABA-A receptors; importantly, this is mechanistic/preclinical evidence rather than proof of an anxiety benefit in humans.
   PubMed – Valerenic Acid and GABA-A Receptors