Ashwagandha vs. L-Theanine: Which is Best?

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    In this article, we’ll cover the basics of each supplement, how they work, and other important things to know.

    Ashwagandha and l-theanine are popular supplements that are often compared because they can both work to support healthy stress responses. However, they’re different in key ways, and their differences can determine whether one or the other might work better for you. In this article, we’ll cover the basics of each supplement, how they work, and other important things to know.

    What is ashwagandha?

    Ashwagandha is an adaptogenic herbal supplement (like Rhodiola and holy basil), known by its plant name as Withania somnifera. It is commonly used in traditional herbal medicinal approaches like Ayurveda.

    What is L-theanine?

    L-theanine is an amino acid that is naturally found in green tea and other types of tea leaves. Unlike some other amino acids, it cannot be used to form proteins in the body.

    Which is better for stress management?

    Both ashwagandha and l-theanine are used to support various aspects of healthy stress responses and calm. But they work differently, and might produce entirely different effects.

    As an adaptogen herb, ashwagandha works primarily by supporting the body’s balanced response to stress. It’s also been shown to be helpful to support healthy sexual wellness, sleep, cognition, immune system responses, and more.

    Ashwagandha can support feelings of calm and resilience, and it is presumed that this is partly attributable to its effect on cortisol levels. Studies are still needed to fully confirm this mechanism. Clinical research has documented that ashwagandha works significantly better than a placebo at reducing a person’s perception of stress (44% compared to only 5% in the placebo group).

    L-theanine can support relaxation, calm, positive outlook, and focus. It isn’t stimulating and has also been shown to help with sleep and feelings of mental overwhelm. It can influence cortisol levels—a study of adults who took l-theanine still had balanced cortisol three hours after a stressful event compared to those who received a placebo.

    Because everyone experiences stress in their own individual way, it’s not possible to know which one might work best for you. If you’re seeking stress management support, your healthcare provider can discuss possible options that might work for you based on your individual needs.

    Ashwagandha vs. L-theanine: A Complete Comparison

    Even though these are both popular supplements, they work differently. Here’s a complete comparison of their function, benefits, mechanisms, dosages, side effects, and more.

    Origin: Adaptogens (Ashwagandha) vs. Amino Acids (L-Theanine)

    Ashwagandha and l-theanine do not belong to the same category of supplements. Ashwagandha is an adaptogen herb, while l-theanine is an amino acid. Ashwagandha is sourced from the leaves and root of a plant, while l-theanine is extracted as a component of tea.

    Primary benefits of Ashwagandha vs L-theanine

    Ashwagandha and l-theanine have some overlapping benefits, but also some differences.

    The main benefits of ashwagandha are:

    The main benefits of l-theanine are:

    How the supplements work

    Ashwagandha supplements and l-theanine have many overlapping benefits, but they work in entirely different ways.

    • Ashwagandha mechanism of action: Works similarly to GABA and helps to activate the parasympathetic nervous system, decrease cortisol, and modulate the body’s hormonal and energy reactions.

    • L-theanine mechanism of action: Crosses the blood-brain barrier and interacts with serotonin, dopamine, and is a glutamate antagonist (meaning that it has a calming effect rather than an excitatory effect). It also interacts with the endocannabinoid system and supports alpha-wave activity in the brain, which are linked to calm and relaxation, and reduces beta and theta brain waves (excitatory and restless).

    Recommended Dosage

    Because ashwagandha and l-theanine are entirely different ingredients, the dosages are different.

    • Ashwagandha: Ranges from 500600 mg daily, but can vary depending on the formulation and product. Always follow the recommendations on the specific product you are taking or what your healthcare provider recommends.

    • L-theanine: Ranges from 200–400 mg daily, but varies based on formulation and product. Follow the instructions on the specific product that you take and what your healthcare provider recommends.

    Time to Take Effect

    Ashwagandha and l-theanine have distinct differences in how long they take to produce an effect.

    • Ashwagandha: Works when taken consistently after days or weeks, with many clinical trials noting benefits after weeks. It is unlikely to be effective if only taken sporadically.

    • L-theanine: Works quickly, typically reaching peak concentrations after 50 minutes. It does not have long-lasting or cumulative effects.

    Potential Side Effects

    Both ashwagandha and l-theanine are generally well tolerated and are not notable for adverse effects or responses, especially when they are taken at recommended doses.

    People who have immune system conditions should use caution with ashwagandha, as should those who are allergic to nightshades (bell peppers, eggplant) since ashwagandha comes from the same plant family.

    Daily supplementation with l-theanine at 200 mg didn’t reveal any adverse effects in a small study group.

    Can I use Ashwagandha and L-theanine together?

    Before starting any supplements, you should always check with your doctor. But generally, there are no known interactions between ashwagandha and l-theanine. Some providers may suggest the benefits of combining the two, notably since l-theanine works quickly and with short-term effects, while ashwagandha takes days or weeks to work, but has longer-term impacts.

    How to Choose the Right Supplement for You

    If you are searching for a supplement to support healthy stress responses, resilience, and relaxation, both ashwagandha and l-theanine represent potential options. What works best for you depends on several factors. Ultimately, your healthcare provider is the best source to help you decide.

    • Other things to consider:
    • If you have tried either before and had a positive (or negative) experience
    • Whether you are looking for consistent, daily support or just as-needed help
    • The inactive ingredients in each of the supplements, which can be important considerations if you have food allergies
    • Your dietary preferences (such as vegan or vegetarian) and how each product is formulated
    • Cost and number of servings per bottle

    The Bottom Line

    There are so many sources of stress in everyday life. In addition to a healthy diet, regular physical activity, and other important elements of self-care (like good sleep hygiene and hydration), supplements like ashwagandha and l-theanine can be effective support for tension and perceived stress. They can provide as-needed or longer-term support, and in many cases, are well-tolerated. Work with your healthcare provider to figure out the best option for you.

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    Laurel Ash, ND
    Laurel Ash, ND: Medical Content Reviewer
    Laurel Ash, ND is a board-certified Naturopathic Physician. She holds additional credentials with a master’s in integrative mental health. Dr. Ash graduated from the National University of Natural Medicine in 2019. Dr. Ash practices in Oregon and Washington where ND’s scope of practice includes primary care. Using the best tools of allopathic/conventional medicine with the holistic tenants of naturopathic medicine has created a powerful force of healing for the patients in her practice. Dr. Ash focuses on combining integrative/functional health modalities with evidence-based medicine. She has experience as a medical reviewer in the holistic medicine field and partners with companies and practitioners to produce science-backed content for readers and consumers interested in holistic medicine. She is passionate about blending the strengths of allopathic and integrative medicine to transform the healthcare industry, empowering people with an understanding of all their options on their wellness journey.
    Mia McNew, MS
    Freelance Contributor
    Mia McNew is a nutrition science researcher with bachelor's and master's degrees in nutrition science and biochemistry. She holds additional certifications in clinical nutrition and formerly managed a private nutrition practice focusing on fertility and the management of chronic health and autoimmune disorders. She is currently pursuing a PhD in human nutrition with a research focus on disability, underserved populations, and inequities in popular nutrition therapy approaches. She has extensive experience as a fact-checker, researcher, and critical research analyst and is passionate about science and health communications that provide practical support.