This Ayurvedic staple still looks promising for stress, sleep, and hormones, but fresh data in 2025 is forcing a more careful, science-first look.
Stress, poor sleep, and hormone issues are now so common that many people reach for “adaptogens” before they ever speak with a clinician. Ashwagandha has become the star of that trend, often marketed as a natural fix for everything from burnout to low testosterone.
The truth is more interesting and a bit more complicated. Research in the last few years confirms some genuine benefits for stress, sleep, and reproductive health, but it also highlights rare safety problems and a lot of overpromising. Used thoughtfully, ashwagandha can be a useful tool, yet it is not a magic switch for performance or longevity.
Key Takeaways
- Ashwagandha can modestly reduce anxiety symptoms, improve sleep quality, and slightly lower cortisol, but the benefits are usually small to moderate, not dramatic.
- For sleep, standardized root extracts around 600 mg per day taken consistently for 6 to 12 weeks show the most reliable results.
- Evidence for exercise performance, muscle gain, and testosterone is mixed and often comes from small, short, or brand-funded trials, so expectations should stay conservative.
- Rare but documented cases of liver injury and thyroid overactivity have been linked to ashwagandha, especially at higher doses or in multi-ingredient formulas.
- People with organ transplants, liver disease, thyroid disorders, pregnancy, or on immunosuppressants should avoid or be extremely cautious with ashwagandha.
- The smartest approach is a short, supervised experiment at moderate doses, paired with good lifestyle habits, not casual long-term mega-dosing.
What Is Ashwagandha, Really?
🌿 Ashwagandha, or Withania somnifera, is a shrub long used in Ayurveda for stress, fatigue, and vitality. Modern supplements usually rely on root extracts packaged in capsules, tablets, powders, or liquids.
These extracts often list a percentage of withanolides, a family of compounds believed to drive many of ashwagandha’s effects. In practice, products can vary in how they are extracted and how many withanolides they provide. That variation helps explain why some studies find clear benefits while others see little change.
For biohackers and health optimizers, ashwagandha is usually aimed at five big areas: stress and anxiety, sleep, hormonal health, exercise performance, and mental performance.
Stress, Anxiety, and Cortisol: A More Nuanced Picture
😰 Ashwagandha is still best known as a stress and anxiety supplement, and there is decent evidence that it can help. Multiple controlled trials and meta-analyses show modest reductions in anxiety scores and drops in cortisol compared with placebo, especially in people with mild to moderate stress.
At the same time, newer pooled analyses suggest that the story is not perfectly straightforward. Some recent work finds that while cortisol levels fall, perceived stress scores do not always improve as clearly as earlier research suggested. In other words, biology might shift more than subjective experience.
😌 For practical use, that means ashwagandha is likely to feel like a gentle downshift rather than an instant calm button. It works best alongside the basics: a reasonable workload, light and movement during the day, and some form of mental hygiene such as breathing, therapy, or meditation.
Ashwagandha and Sleep: One of the Strongest Use Cases
😴 Sleep is where ashwagandha probably earns the most legitimate praise. A collection of clinical trials, including people with insomnia and people who simply sleep poorly, show improvements in sleep onset, sleep duration, and sleep efficiency.
The pattern across studies is fairly consistent:
- Standardized root extracts are used, usually in capsule form.
- Total daily doses cluster around 600 mg, sometimes a bit lower or higher.
- Benefits tend to appear after 6 to 8 weeks of steady use rather than a few nights.
🌙 For many people, that translates into slightly easier sleep onset, fewer night awakenings, and a sense of waking more restored. It is not on the level of a prescription sedative, and it should not be treated as one, but it can be a respectable secondary sleep tool, especially when sleep hygiene is in place.
Mood, Cognition, and Brain Health
🧠 Ashwagandha has also been studied in various mental health and cognition settings. Trials in people with anxiety, mild depression, bipolar disorder, and OCD suggest that the herb can modestly improve anxiety scores, some aspects of cognition, and subjective well-being.
Results are encouraging but come with big caveats. Most studies are small, often under 100 participants, and they frequently use specific branded extracts that may not match what you see on a supplement shelf. Effects tend to be modest and may not hold in more severe psychiatric conditions.
🧩 The realistic framing is that ashwagandha can be a supportive nudge for mood and brain function, not a replacement for therapy, medication when needed, or lifestyle factors like exercise and social connection.
Testosterone, Fertility, and Sexual Health
💪 This is one of the most hyped areas and one that attracts many male biohackers.
Several small clinical trials in men with fertility issues or low-normal testosterone have found that ashwagandha can increase testosterone levels, improve semen parameters, and support sexual function scores. The doses in these studies often range from 600 to 1,000 mg per day, with some higher, over about 8 to 12 weeks.
However, results in healthy, trained men are less consistent. Some studies show improved testosterone or strength, while others see little advantage compared with placebo. Many trials are short, use branded products, and involve relatively small sample sizes.
For someone with genuine fertility concerns or borderline testosterone, ashwagandha may be worth a time-limited experiment, ideally under medical supervision. It still sits behind resistance training, good sleep, adequate calories, and a full medical workup in the priority list.
Exercise Performance & Recovery
🏃♂️ Early research on ashwagandha and performance looked exciting. Some trials suggested improvements in strength, power, VO₂max, and recovery markers, especially when paired with resistance or endurance training.
More recent studies, including those in athletes performing high-intensity interval training, have not always replicated those results. In some cases, ashwagandha offers no clear advantage over placebo for aerobic performance or training adaptations.
For athletes and serious lifters, the fairest view is that ashwagandha is a “maybe” performance enhancer. It might help a subset of people, particularly those under high stress whose sleep is improved by the herb. It should sit alongside, not above, staples like creatine, structured programming, and nutrition.
Safety, Side Effects, and 2025 Liver Concerns
⚠️ This is where new data really matters.
Most clinical trials report that ashwagandha is well tolerated over 2 to 3 months, with mild side effects such as drowsiness, stomach upset, or loose stools. At this level, it looks similar to many other herbal supplements.
In the real world, however, case reports and series have linked ashwagandha to clinically significant liver injury. People have presented with jaundice, itching, dark urine, and abnormal liver tests after weeks to months of use. Some had underlying liver concerns, others did not. Multi-ingredient formulas make it tough to prove a single culprit, but ashwagandha has repeatedly been present.
Thyroid is the other concern. There are documented cases of thyrotoxicosis after ashwagandha use, with symptoms like palpitations, anxiety, heat intolerance, and tremor. The herb appears to influence thyroid hormone levels in some people, which is a problem if the thyroid is already fragile.
Ashwagandha also has immune-stimulating properties, which is normally a plus, but not for everyone. A transplant patient who was stable on immunosuppressants experienced organ rejection after starting ashwagandha, likely because it undermined the immunosuppressive effect.
🚫 People who should avoid or be extremely cautious:
- Anyone with current or past liver disease
- People with organ transplants or on immunosuppressant medications
- Individuals with known thyroid disorders, especially hyperthyroidism
- Pregnant or breastfeeding individuals, since safety data are very limited
Everyone else still needs to respect the compound. The risk of serious harm seems low but clearly not zero, especially with high doses, long-term continuous use, or poorly regulated products.
Ideal Ashwagandha Dosage & Forms
💊 Most modern research uses standardized root extracts rather than whole plant powders.
Across studies, daily doses typically fall between 120 and 600 mg for stress, anxiety, and sleep, with many landing near 300 to 600 mg per day. Hormone and fertility trials sometimes go higher, up to several grams per day, but that pushes into more speculative territory for both benefit and safety.
A sensible approach for most adults without contraindications:
- Start with 150 to 300 mg once daily, taken with food, for 1 to 2 weeks.
- If tolerated and still promising, increase to 300 mg twice daily or a single 600 mg evening dose, especially for sleep goals.
- Reassess after 8 to 12 weeks and consider cycling off or reducing frequency rather than staying on a high dose indefinitely.
Because products vary, it is worth prioritizing supplements that clearly state:
- Root-only extract
- The percentage of withanolides
- Third-party testing for purity and heavy metals
That will not guarantee safety, but it lowers some of the obvious quality risks.
How Does Ashwagandha Work?
🧬 The mechanisms are still being mapped, but several themes show up again and again.
Ashwagandha appears to influence the stress response system, often called the HPA axis, which can translate into lower cortisol and a more stable reaction to stressors. It also seems to interact with GABA and serotonin signaling in the brain, which may explain some of its calming and sleep-supporting effects.
There is also evidence of antioxidant and anti-inflammatory activity, which might help explain benefits seen in brain, metabolic, and immune markers. Finally, withanolides appear to affect endocrine pathways, including those related to thyroid hormones and sex steroids.
For the average user, the easiest way to think about it is this: ashwagandha works as a broad adaptogen, gently nudging several systems toward balance, instead of a single, highly targeted pathway the way a drug would.
How To Try Ashwagandha Safely
🛠 This is not personal medical advice, but a practical template many health-conscious people use when testing ashwagandha.
1. Pick one clear goal
Choose a primary outcome, such as sleep quality, perceived stress, recovery, or sexual health. When the goal is precise, it is easier to decide if ashwagandha is doing anything meaningful.
2. Take a simple baseline
Before you start, record a week of your normal:
- Sleep quality (0 to 10 score or wearable data)
- Daily stress rating
- Training performance or recovery notes
If you have access to a clinician, consider baseline labs for liver enzymes, thyroid, and hormones when relevant.
3. Start low and monitor
Begin with a low dose once per day for a couple of weeks, then decide if you feel any consistent change. If all is well, increase to a typical research dose and hold it for 6 to 8 weeks.
Pay attention to energy, mood, digestion, and sleep, but also watch for red flags such as jaundice, persistent nausea, chest pounding, or feeling overheated and jittery.
4. Use smart stacking
For many people, ashwagandha works best as part of a simple, thoughtful stack, such as pairing it with magnesium and glycine at night for sleep, or with theanine for smoother daytime focus. Avoid stacking it with unknown multi-herb “boosters,” or with other pills that already include ashwagandha, where you might accidentally double or triple your dose.
After your trial, step back and ask: did this move the needle enough to justify staying on it, given the cost and the small but real safety signals?
FAQ
Does ashwagandha really work for anxiety?
Ashwagandha can reduce anxiety symptoms in many people, but the effect is usually modest. It tends to work best as a helper layered on top of good sleep, movement, and psychological support, not as a single solution for anxiety disorders.
Is ashwagandha safe to take long term?
Long term, the safety of ashwagandha is uncertain because most trials last only a few months and real-world reports now include cases of liver and thyroid problems. Short, time-limited trials at moderate doses are safer than open-ended daily use.
Will ashwagandha boost my testosterone and muscle gains?
Ashwagandha may increase testosterone and improve fertility markers in some men, especially those under high stress or with existing issues, but results in healthy athletes are mixed. It should be seen as a possible small support on top of training, nutrition, and sleep, not as a main driver of muscle growth.
Can I take ashwagandha if I have a thyroid problem?
People with thyroid conditions should be very cautious with ashwagandha, because it has been linked to cases of thyroid overactivity and can influence thyroid hormone levels. Anyone with a thyroid issue should only use it under close medical supervision, if at all.
Is ashwagandha safe during pregnancy or breastfeeding?
Ashwagandha cannot currently be considered safe in pregnancy or breastfeeding because high-quality human data are lacking. Most expert sources recommend avoiding it during these times.
Sources
- Ashwagandha: Fact Sheet for Health Professionals. National Institutes of Health Office of Dietary Supplements.
https://ods.od.nih.gov/factsheets/Ashwagandha-HealthProfessional/ - Effect of Ashwagandha extract on sleep: A systematic review and meta-analysis. PLOS One.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0257843 - Ashwagandha and its effects on well-being and sports performance. Nutrition & Metabolism.
https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/s12986-025-00902-7 - An investigation into the stress-relieving and pharmacological actions of an Ashwagandha extract. Medicine (Baltimore).
https://journals.lww.com/md-journal/fulltext/2019/09130/an_investigation_into_the_stress_relieving_and.67.aspx - Examining the effect of Withania somnifera supplementation on muscle strength and recovery. J Int Soc Sports Nutr.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6438434/ - Efficacy and safety of eight-week therapy with Ashwagandha extract on male sexual health. Eur J Med.
https://ej-med.org/index.php/ejmed/article/view/2304
