Most clinical trials use between 300 and 600 mg of ashwagandha root extract per day, split into one or two doses. That range has shown measurable benefits for stress, sleep, and physical performance across dozens of studies. But the right amount for you depends on which extract you’re using and what you’re taking it for, because not all ashwagandha supplements are created equal.
Why the Extract Type Matters More Than the Milligrams
Ashwagandha’s active compounds are called withanolides, and different branded extracts concentrate them to very different levels. This means 600 mg of one product can deliver a completely different dose of active compounds than 600 mg of another. Three proprietary extracts dominate the market and the research:
- KSM-66: A root-only extract standardized to more than 5% withanolides. The typical study dose is 600 mg per day (two 300 mg capsules).
- Shoden: A highly concentrated extract standardized to 35% withanolide glycosides. Because it’s so concentrated, the effective dose is much lower: 120 mg per day (two 60 mg capsules), delivering about 21 mg of withanolide glycosides.
- Sensoril: Made from both root and leaf, used in several clinical trials, though its exact standardization varies by product.
If your supplement label lists one of these names, match the dose used in studies for that specific extract. If it just says “ashwagandha root extract,” check the withanolide percentage on the label. A product with 5% withanolides is comparable to KSM-66 dosing. A product with no standardization information is harder to dose reliably.
Dosages by Goal
Stress and Anxiety
The most-studied dose for reducing stress and lowering cortisol is 600 mg per day of KSM-66, taken as two 300 mg capsules. Alternatively, 120 mg per day of Shoden (two 60 mg capsules) has been used in trials with similar goals. Both formats have shown reductions in perceived stress and anxiety scores compared to placebo.
Sleep
The same dosing protocols used for stress, 600 mg of KSM-66 or 120 mg of Shoden daily, have also been studied for sleep quality. Most sleep-focused trials had participants take their capsules once or twice daily with milk or water. If sleep is your primary goal, taking your dose in the evening is a reasonable approach, though studies haven’t conclusively proven that nighttime dosing works better than morning dosing for sleep outcomes.
Muscle Strength and Recovery
In an eight-week trial published in the Journal of the International Society of Sports Nutrition, subjects took 300 mg of ashwagandha root extract twice daily (600 mg total), once shortly after waking and once before bed. Compared to the placebo group, those taking ashwagandha showed greater gains in muscle strength and size while following a resistance training program. The 600 mg daily dose taken in two split doses appears to be the standard for exercise-related benefits.
Testosterone
A crossover study in overweight men aged 40 to 70 found that Shoden extract delivering 21 mg of withanolide glycosides per day (two tablets taken together after dinner) led to a 14.7% greater increase in testosterone and an 18% greater increase in DHEA-S compared to placebo over eight weeks. This is a notably small milligram dose (120 mg of extract), but it works because of the high withanolide concentration in Shoden. Taking a standard 600 mg KSM-66 dose for testosterone hasn’t been studied as directly.
When to Take It
The most common protocol in clinical research is one or two doses per day, taken with food or milk. Beyond that, timing recommendations are more practical than scientific. If you’re using ashwagandha primarily for sleep, an evening dose makes intuitive sense. If you’re using it for daytime stress or workout recovery, splitting the dose between morning and evening (as the strength study did) is a well-tested approach. There’s no strong evidence that taking it on an empty stomach improves absorption, and some people find it easier on the stomach with food.
How Long Before You Notice Results
Most people report noticing changes within two to four weeks of daily use. Some feel a difference within the first week, particularly with stress and sleep. Others need up to six weeks before benefits become clear. In clinical trials, outcome measurements are typically taken at the four- to eight-week mark, which gives a realistic window for what to expect. Ashwagandha is not something you’ll feel working after a single dose the way you’d notice caffeine or melatonin.
It’s also worth noting that researchers don’t yet know whether taking breaks from ashwagandha helps maintain its effectiveness over time, or whether continuous daily use is fine indefinitely. Most studies last 8 to 12 weeks, so long-term data beyond that window is limited.
Upper Limits and Safety
In a 90-day animal toxicity study of KSM-66, no adverse effects were observed even at very high doses (the equivalent of far more than any human would take as a supplement). In human trials, doses up to 600 mg of root extract per day are consistently well tolerated, with side effects generally limited to mild digestive discomfort in some people. Going above 600 mg hasn’t been shown to produce better results, and there’s no reason to assume more is better.
That said, ashwagandha isn’t appropriate for everyone. The National Institutes of Health flags several groups who should avoid it:
- Pregnant or breastfeeding women: Ashwagandha should not be used during pregnancy or while nursing.
- People with thyroid or autoimmune disorders: Ashwagandha can affect thyroid hormone levels and immune function.
- People with hormone-sensitive prostate cancer: Because it can raise testosterone levels.
- People taking certain medications: It may interact with drugs for diabetes, high blood pressure, seizures, thyroid conditions, and immunosuppressants, as well as sedatives.
- People scheduled for surgery: It may affect sedation and blood pressure during procedures.
A Practical Starting Point
If you’re buying a KSM-66 product, 300 mg once or twice daily (up to 600 mg total) is the dose backed by the most research. If you’re buying a Shoden product, 120 mg daily is the studied dose. Start at the lower end, one capsule per day, for the first week to see how your body responds, then move to the full dose if you tolerate it well. Look for a supplement that lists its withanolide content or uses a named, standardized extract, since unstandardized products make it difficult to know what you’re actually getting.