Can You Take Ashwagandha and L-Theanine Together?

Can you take ashwagandha and L-theanine together? Yes, and it’s a common stack, because they target stress in different but complementary ways. 

Ashwagandha is an adaptogen used in traditional Indian medicine that helps the body tolerate chronic stress. At the same time, L-theanine is a calming amino acid found in green tea that promotes relaxed alertness. 

This article explains how each works, what the clinical evidence says, common benefits people report (better sleep quality, lower stress and anxiety levels, clearer focus), safety caveats, practical dosing and timing, and whether adding magnesium makes sense. 

Evidence from randomized trials and NIH summaries shows ashwagandha can reduce anxiety scores and lower morning cortisol in chronically stressed adults, supporting its role in cortisol control and stress reduction. 

TL;DR

Yes, you can generally take ashwagandha and L-theanine together. Ashwagandha helps blunt stress-hormone (cortisol) spikes and build longer-term resilience. 

At the same time, L-theanine promotes alpha-wave brain activity and calm alertness. Together, they can reduce stress, support sleep quality and nervous system function, and sharpen focus. 

Start with moderate doses, avoid use in pregnancy, check for interactions with sedatives, thyroid or blood-pressure meds, and run it by a healthcare professional if you have a chronic medical condition. 

TRIBE ORGANICS — KSM-66 Ashwagandha (600 mg, 120 capsules)

TRIBE’s formula uses KSM-66, a well-known root-only ashwagandha extract used in many clinical trials, and the listing highlights USDA organic certification and third-party testing claims. 

It’s available in a high, trial-style dose (600 mg) per serving and comes in a value-sized bottle — a convenient option if you plan to take a daily adaptogen. 

• KSM-66 root extract; 600 mg per serving (clinical-style dosing).
• 120 capsules per bottle (good for longer trials). 
• USDA Organic / GMP claims on the product page. 

Who it’s best for: Individuals seeking a standardized, root-only ashwagandha supplement at a dose commonly used in RCTs, who prefer an organic option and a larger bottle for ongoing use.

How I’d use it (example): Start with 300 mg once daily for a week to check tolerance, then move to 300 mg twice daily (or follow the label / your clinician’s advice). Always check thyroid meds or other interactions first.

Thorne — Theanine (200 mg, 90 capsules)

Thorne is a clinician-facing, third-party-tested brand with a reputation for clean manufacturing. Their L-theanine product provides a clear 200 mg dose per capsule — a convenient, research-friendly dose for calming/alpha-wave effects without extra fillers. 

• 200 mg L-theanine per capsule.
• 90 capsules per bottle; third-party testing / practitioner-recommended brand messaging. 

Who it’s best for: Individuals seeking a pure, pharmaceutical-grade L-theanine dose for acute use (e.g., before a stressful meeting or in the evening for sleep support) or to stack with an adaptogen like ashwagandha.

How I’d use it (example): 100–200 mg when you want calm focus (try 100 mg first) or 200 mg in the evening if you’re using it to support sleep. Don’t combine with sedating meds without consulting a provider.

Quick comparison/stacking tip: the Tribe KSM-66 (ashwagandha) covers daily cortisol-control needs (adaptogen), while Thorne’s theanine is ideal for acute calm/focus or evening relaxation. Together they’re a straightforward stack: ashwagandha daily + L-theanine as needed (or both daily at conservative doses). Always confirm with your healthcare professional if you’re on medications (sedatives, thyroid meds, or blood-pressure drugs) or pregnant/breastfeeding.

How Each Supplement Works 

What L-theanine does

L-theanine is a calming amino acid found naturally in green tea that’s prized for producing relaxed alertness without heavy sedation. It crosses into the brain and modulates neurotransmitters such as GABA, dopamine and serotonin, which helps smooth out the nervous system’s response to stress. 

On EEG tests, L-theanine reliably alters alpha brain waves, which are patterns associated with relaxed wakefulness and improved attention, and some trials also show reductions in salivary cortisol during acute stress challenges. 

Taken together, these effects explain why people reach for L-theanine for calmer focus before meetings or to ease into sleep. 

What ashwagandha does

Ashwagandha is an adaptogen used in traditional Indian (Ayurvedic) medicine; its active compounds—steroidal lactones called withanolides—appear to support the body’s stress response, contributing to its possible health benefits. 

Clinical trials show ashwagandha supplements can lower cortisol levels and reduce validated measures of anxiety, suggesting it helps reset the hypothalamic-pituitary-adrenal axis over weeks of use. 

Because of that, longer-term action, many people pair ashwagandha with theanine: ashwagandha targets chronic stress and anxiety levels and hormonal balance. At the same time, L-theanine addresses fast, nervous-system calming and attentional effects. 

The NIH Office of Dietary Supplements and randomized trials (e.g., Lopresti and colleagues) summarize this evidence but note that more large, long-term studies would strengthen conclusions.

Why People Stack Them — Complementary Benefits

People often combine ashwagandha and L-theanine because the two supplements work on stress from different angles, so together they cover both fast, nervous-system imbalances and slower hormonal regulation. 

L-theanine produces rapid calming effects by nudging the brain toward alpha brain waves, which supports calm focus and improved attention without heavy sedation. 

Ashwagandha, by contrast, acts more slowly as an adaptogen. Its withanolides help blunt repeated cortisol spikes and build longer-term resilience to chronic stress. 

That complementary action is exactly why clinicians and supplement writers recommend pairing them: one gives near-term nervous-system balance, the other helps manage cortisol levels over weeks. 

Stacking them tends to show four practical benefits people care about:

• Improve sleep quality: L-theanine can ease the transition to relaxed wakefulness, while ashwagandha’s HPA-axis effects can help normalize sleep patterns over time. 
• Anxiety reduction: Acute anxiety or “spikes” may be damped quickly by L-theanine’s calming effects, and chronic stress and anxiety levels often fall with several weeks of standardized ashwagandha.
• Improved cognitive function/attention: By promoting alpha-dominant brain waves and smoothing neurotransmitter swings, L-theanine can improve focus; combined with reduced background stress from ashwagandha, many users report clearer thinking and better task performance.
• Overall relaxation pathways: The stack targets multiple relaxation pathways, including neurotransmitter modulation (GABA/serotonin/dopamine), EEG patterns (alpha), and endocrine control (cortisol), so the effect is broader than either supplement alone.

Bottom line: ashwagandha + L-theanine is a logical, evidence-informed combo for people wanting both immediate calm and longer-term stress management. As always, start conservatively, monitor how you feel (sleep quality, anxiety reduction, daytime focus), and check with a healthcare professional if you take other medications or have medical conditions.

Evidence Summary — What the Studies Actually Show 

Here’s a concise, evidence-focused look at the trials and reviews most relevant to L-theanine and ashwagandha, including what they measured, what they found, and where the gaps are.

Quick take: Human trials show consistent, moderate evidence that ashwagandha can reduce anxiety scores and lower morning cortisol over weeks, while L-theanine produces rapid changes in brainwave patterns (alpha-band activity) and has shown occasional reductions in salivary cortisol and state anxiety in acute stress tests. High-quality long-term trials of combined formulations are limited.

Key trials/reviews:

• Evans et al., 2021 — L-theanine (acute stress model): randomized, triple-blind crossover testing a single dose of AlphaWave® L-theanine found increases in relaxing brainwave patterns, lower salivary cortisol, and reduced self-reported state anxiety during an acute stress challenge. Good for showing acute calming/EEG effects. 
• Gómez-Ramírez et al., 2009 — L-theanine and EEG: laboratory EEG study showing L-theanine alters alpha-band oscillatory activity during cognitive tasks — a mechanistic finding that helps explain the “calm but alert” effect.
• Lopresti et al., 2019 — Ashwagandha RCT: 8-week, randomized, double-blind, placebo-controlled trial in chronically stressed adults reported significant reductions in anxiety scores and morning cortisol with standardized ashwagandha extract, supporting its role in cortisol control and anxiety reduction.
• Systematic reviews/meta-analyses (ashwagandha): multiple reviews and meta-analyses conclude that ashwagandha reduces stress and anxiety compared to placebo, and can lower cortisol, but note heterogeneity across extracts, doses, and study quality. Recent meta-analyses reinforce a modest, clinically meaningful effect while calling for larger, standardized trials.
• NIH / ODS summary: The Office of Dietary Supplements summarizes current evidence and safety considerations for ashwagandha and flags the need for more long-term safety data and standardized products. Use ODS as a reliable clinical summary.

What the evidence doesn’t show (yet):

• There are a few large, long-duration randomized trials testing ashwagandha + L-theanine together as a combined intervention; most evidence is for each ingredient alone.
• Product-level claims for combination supplements are often supported by small pilot studies or by extrapolation from single-ingredient trials rather than by independent, high-quality RCTs. 

Practical Implication: The evidence supports using L-theanine for acute calming/attention changes (EEG/cortisol) and ashwagandha for longer-term stress/cortisol management. If you plan to try a stack, treat it as an informed experiment: prefer standardized extracts, start at conservative doses, and monitor sleep quality, anxiety scores, and any medication interactions, then discuss with a healthcare professional. 

Safety, Side Effects & Who Should NOT Combine Them 

Both ashwagandha and L-theanine are generally well tolerated at common supplemental doses, but they aren’t risk-free. Mild side effects reported across trials and product reviews include drowsiness, gastrointestinal upset (nausea, diarrhea), headache, and occasional dizziness. 

The human L-theanine trial literature describes good short-term tolerability, and ODS summarizes ashwagandha safety data while flagging the need for more long-term information. 

Specific cautions to keep in mind:

• Pregnancy & breastfeeding: Avoid using ashwagandha (and be cautious with other herbal extracts) in pregnancy and while breastfeeding unless a clinician advises otherwise; ODS and other federal resources recommend caution because safety data are limited.
• Thyroid medications / autoimmune thyroid disease: Some studies and case reports suggest ashwagandha can alter thyroid hormone levels in susceptible people; if you take thyroid replacement or have an autoimmune thyroid or overactive immune function condition, discuss ashwagandha with your clinician before starting it. 
• Sedatives/benzodiazepines / other CNS depressants: Ashwagandha may have mild sedative effects and could theoretically increase drowsiness when combined with benzodiazepines, sleep medicines, or strong sedatives. Use caution and consult your provider if you’re already taking sedating medications. 
• Blood-pressure and blood-sugar medications: Ashwagandha has been reported to lower blood pressure and influence blood-glucose in some studies; combining it with antihypertensives or antidiabetic drugs could potentiate those effects, so monitor levels and check with your prescriber. 
• Surgery: Stop herbal supplements before elective surgery if advised by your surgeon or anesthesiologist—herbal sedatives or metabolic effects can interfere with anesthesia and recovery.

Interaction note: Always tell a healthcare professional about any dietary supplements you take—especially if you have a chronic medical condition or take prescription drugs. That conversation should cover doses, timing, and monitoring plans (blood pressure, thyroid labs, glucose, or any new symptoms). 

If you decide to try a stack, start at conservative doses, try one ingredient at a time so you can spot side effects, and keep a short symptom log (sleep quality, daytime drowsiness, GI symptoms, mood/anxiety). If anything unexpected happens, stop the supplement and contact your healthcare professional.

Dosing, timing & absorption tips 

Typical dose ranges (what the trials used)

• L-theanine: most clinical work and consumer guidance use 100–200 mg per dose for calm/alpha-wave effects; single-dose studies that show EEG and cortisol effects commonly use ~100–200 mg. Start low (100 mg) to test how it affects you, then try 200 mg if needed.
• Ashwagandha: randomized trials commonly use 300–600 mg/day of a standardized root extract (many studies use 300 mg twice daily or 600 mg once daily of a KSM-66–type root extract) for anxiety and cortisol outcomes. Protocols and standardization vary, so follow the product label or the clinician’s advice. 

When to take (practical timing advice)

• L-theanine: works quickly for many people, so use it acutely when you want calm focus (e.g., 30–60 minutes before a stressful meeting) or in the evening if it helps you wind down. You can split doses (100 mg morning + 100 mg afternoon/evening) if you want steady support.
• Ashwagandha is intended as a daily adaptogen for emotional and brain health. For optimal benefits, take it consistently (morning or evening) for several weeks to see improvements in the HPA-axis and cortisol levels. If ashwagandha makes you slightly sleepy, try it in the evening; if it increases energy for you, take it in the morning. Use the term daily dose when tracking. 

Absorption & “how to get the most” (evidence varies — use “optimal absorption” cautiously)

• Some practitioners recommend taking L-theanine away from a heavy meal for faster onset of effects (so it reaches the bloodstream sooner). Still, high-quality trials don’t uniformly require fasting, and real-world responses vary.
• Ashwagandha is often taken with food in clinical trials; some extracts may be better absorbed when taken with a meal containing some fat. Evidence on absorption differences between brands/extracts is limited, so look for standardized root extracts and follow label directions for optimal absorption.

Practical tips

• If you’re stacking, consider starting one ingredient at a time (e.g., L-theanine for a week, then add ashwagandha) so you can detect benefits or side effects. Track outcomes (sleep quality, daytime focus, anxiety) for at least 2–4 weeks to assess ashwagandha’s effects.
• Always confirm timing/dose with a healthcare professional if you use prescription meds, have a chronic medical condition, or are pregnant/breastfeeding.

What About Adding Magnesium? — Can You Take Ashwagandha, L-theanine & Magnesium Together? 

Short answer: yes — many combo products and clinical nutrition formulas pair ashwagandha + L-theanine + magnesium (often as magnesium glycinate) because the ingredients act on complementary pathways: L-theanine for acute calming and alpha-wave support, ashwagandha for HPA-axis/cortisol control, and magnesium for nervous-system relaxation and sleep support. Consumer formulations and clinician products (for example, Igennus’s adaptogen complexes) commonly include this trio. 

Why people add magnesium: Magnesium (especially glycinate or threonate forms) may modestly improve sleep quality and reduce nervousness in individuals with suboptimal magnesium status. When combined with L-theanine and ashwagandha, it can reinforce relaxation pathways without causing dramatic sedation. 

Reviews and practical guides note that the combination is frequently used for evening support and sleep-focused stacks.

Safety/monitoring note: check your total magnesium intake (including in a varied and balanced diet + supplements) and be cautious with renal impairment—the kidneys excrete magnesium, and people with significantly reduced kidney function risk hypermagnesemia if supplementing. 

If you take blood-pressure or blood-sugar medications, monitor those parameters because ashwagandha (and magnesium) can influence them. If in doubt, ask your healthcare professional about the combination, dosing schedule, and whether particularly magnesium in a glycinate form is appropriate for you. 

Practical stack idea: ashwagandha once or twice daily (per label), L-theanine 100–200 mg as needed (or 100 mg twice daily), and magnesium glycinate 100–300 mg elemental magnesium in the evening if sleep support is the goal—start low, monitor sleep quality, and adjust under clinician guidance.

How to Pick Supplements (Forms, Standardized Extracts, and What “Most Scientifically Supported Form” Means) 

Picking reliable forms matters more than brand hype. For L-theanine, choose a product labeled as pure L-theanine (often shown as “L-theanine” or “theanine”); specifications like S- or L-form are rarely necessary for consumers. 

If you prefer whole-food sources, natural green tea or green tea extract (or matcha) gives L-theanine plus small amounts of caffeine and other polyphenols — useful if you want mild stimulation along with calm. Clinical and review studies of L-theanine’s EEG and attention effects typically use isolated L-theanine at 100–200 mg doses, so look for that dosage on the label. 

For ashwagandha, the most scientifically supported form is a root-only extract that is standardized for withanolides (the active steroidal lactones). Many RCTs use standardized root extracts—KSM-66 and similar root extracts are what manufacturers claim when they cite clinical trials—so prefer products that state “root extract” and list withanolide content rather than vague “full-spectrum” or unspecified whole-plant extracts. 

The NIH Office of Dietary Supplements and recent narrative reviews note that the bulk of clinical evidence uses standardized root extracts. 

Also, check other ingredients: avoid products that hide doses behind proprietary blends and scan for common fillers or excipients like magnesium stearate or rice extract blend if you’re sensitive to additives. 

Read the supplement facts panel, confirm batch testing or third-party certification where possible, and prefer manufacturers that disclose extract standardization and serving size (this helps with optimal absorption and reproducible daily dose).

Practical One-Week Trial Plan — How To Try the Stack Safely 

This short, stepwise plan helps you test the stack while tracking effects and safety.

Day 1–7 — Start with L-theanine only: take 100 mg in the morning and, if needed, 100 mg in the early afternoon (or 100–200 mg 30–60 minutes before a stressful event). Log your sleep quality, daytime focus, and any drowsiness. (How to take: note timing relative to meals.) 

Day 8–14 — Add low-dose ashwagandha: begin 300 mg daily of a standardized root extract (or 300 mg once daily per the label); maintain the same L-theanine schedule. Track anxiety scores (simple 0–10 scale), sleep quality, and energy levels over time. Clinical benefits for ashwagandha generally accrue over weeks, so treat this as an initial 2–4 week experiment. 

Optional week 3 — Introduce magnesium (if desired): add a modest evening dose (e.g., magnesium glycinate providing ~100–200 mg elemental magnesium) to support sleep quality—but check total magnesium intake and kidney function first.

Safety checklist: read the label for extract standardization and total daily dose, monitor body’s nutrient stores by keeping a balanced diet, note any medication changes, and stop if you experience severe side effects (marked GI upset, big mood swings, or abnormal heart rate). If you have a chronic medical condition, an issue affecting your immune system or take prescription meds, talk with a healthcare professional before trying the stack. 

FAQs 

Can you take ashwagandha and L-theanine together?

Yes — can you take ashwagandha and L-theanine together? In most healthy adults, this stack is commonly used and generally well tolerated: ashwagandha supports longer-term cortisol control while L-theanine gives faster calming/alpha-wave effects. Start low, watch for drowsiness, and check meds. If you have a chronic medical condition or take prescriptions, talk with a healthcare professional first. 

Can you take L-theanine and ashwagandha together with magnesium?

Short answer: yes — can you take L-theanine and ashwagandha together with magnesium? Many consumer formulas combine magnesium (often glycinate) with L-theanine and ashwagandha to boost evening relaxation and sleep quality; dosing caveat: monitor total elemental magnesium (diet + supplements) and avoid high doses if you have kidney impairment. Consult your clinician for a safe daily dose. 

Will taking L-theanine and ashwagandha make you drowsy?

Possibly, dose-dependent. L-theanine usually produces calm alertness (not heavy sedation) but can help sleep quality at higher evening doses; ashwagandha can be mildly sedating in some people—try timing (ashwagandha in the evening if it causes sleepiness) and lower doses if daytime drowsiness occurs. Track effects and adjust. 

Does L-theanine cross the blood-brain barrier?

Yes — studies and reviews indicate L-theanine crosses the blood-brain barrier and reaches the CNS, where it influences neurotransmitters and EEG patterns (alpha activity). This helps explain its acute calming and attention effects. 

Can these supplements lower cortisol?

Ashwagandha has the strongest evidence for lowering cortisol levels and promoting the body’s hormonal balance—RCTs report reduced morning cortisol and improved stress scores after weeks of use. L-theanine has shown occasional acute reductions in salivary cortisol in stress-challenge studies, but its main effects are on EEG/relaxation. 

Who should avoid ashwagandha or L-theanine?

Avoid or use caution in pregnancy/breastfeeding, uncontrolled thyroid disease, severe kidney disease, or when taking sedatives, thyroid meds, antihypertensives, or anticoagulants—stop before surgery if advised. Always tell your healthcare professional about supplements if you have a serious medical condition. 

What’s the best time of day to take them? 

Practical guide: Use L-theanine acutely (100–200 mg) before stressful events or in the evening for sleep. Take ashwagandha as a consistent daily dose (300–600 mg/day) morning or evening, depending on personal response. Evaluate effects over both the duration (2–4 weeks). 

Are there benefits for cognitive function?

Yes — L-theanine’s effect on alpha brain waves supports calm focus and can improve cognitive function in attention tasks; reduced background stress from ashwagandha may further help clear thinking over time. 

Can You Take Ashwagandha and L-Theanine Together– Final Thoughts 

Yes — combining ashwagandha and L-theanine is a reasonable, evidence-informed approach for people aiming for both immediate calm and longer-term stress resilience. Prefer standardized, root-only ashwagandha and pure L-theanine. Start conservatively, and monitor sleep quality, anxiety, and daytime alertness.