Ashwagandha: what it’s really for, when to take it and who should avoid it

Your mind has been racing for weeks, you struggle to switch off at night and someone has mentioned ashwagandha. Before you buy the first one you see, there are four things you should know: what has actually been studied, how long it takes to notice anything, how to tell a good extract from a poor one and, above all, whether you can take it at all.

Ashwagandha (Withania somnifera) is a plant from the Ayurvedic tradition, also known as Indian ginseng, whose root has been used for centuries during periods of physical and mental strain. Today it is one of the most widely studied botanicals in relation to stress and rest. It is not suitable for everyone: pregnant and breastfeeding women, minors and people with thyroid or liver conditions should avoid it.

What is ashwagandha used for?

Ashwagandha is used mainly in two situations: periods of sustained stress and difficulty switching off and sleeping well. It is the reference plant in Ayurvedic medicine for those stretches when body and mind are running on empty.

Over the past two decades, clinical trials with root extract have been published in adults with high stress levels, in people with sleep problems and in healthy volunteers. Participants took the extract for 8 to 10 weeks and reported feeling calmer, sleeping better and facing the day with more composure than those on placebo. If you want to dig deeper, the NIH fact sheet gives a good summary of the current evidence.

What happens to my body when I take ashwagandha?

The first thing to know is that you will not notice anything on day one. It is neither a stimulant nor a sedative: it does not give you a rush and it does not knock you out. Its action is gradual and builds up with daily use.

This is what study participants described, and the order in which it tends to appear:

1. Weeks 1 to 2: a sense of being less reactive to the situations that used to get to you. Some people find it easier to fall asleep.

2. Weeks 3 to 4: a greater sense of calm during the day and better-quality rest. In studies that measured cortisol, the main stress hormone, blood levels dropped compared with the placebo group.

3. Weeks 6 to 8: this is when the largest differences from placebo were observed: less perceived stress, more restorative sleep and, as a result, more energy and focus during the day.

In short: a body that copes better with built-up tension and rests better, rather than an instant effect. If at any point something doesn’t feel right (persistent digestive discomfort, unusual tiredness), stop and speak to your doctor.

When should you take ashwagandha, and how?

1. Preferably in the morning, then adjust to how it suits you. People respond to ashwagandha very differently: some find it helps them get going, others find it helps them unwind. For most, the time that works best is the morning, in line with the body’s natural cortisol peak, even when the goal is better rest. Some people find that taking it right before bed leaves them more alert rather than relaxed. Start in the morning and, if after a few weeks you find another time suits you better, switch.

2. Always with food. Ashwagandha root can cause mild digestive discomfort on an empty stomach. Taking it with breakfast avoids this in most cases.

3. Give it time. Clinical studies observed effects between the fourth and tenth week of daily use. If you stop after ten days because you “don’t feel anything”, you haven’t given it a chance.

4. Take it in cycles and never exceed 3 months in a row. The usual pattern is 8 to 12 weeks of continuous use, followed by a break of 2 to 4 weeks before starting again. There are no safety studies beyond 3 months of continuous use, so that is a limit you should not cross under any circumstances.

Who should not take ashwagandha?

European guidance advises against use for:

• Pregnancy and breastfeeding: the plant has a traditional use as an abortifacient and there are no safety data for these stages.

• Under-18s.

• Thyroid conditions: it may interfere with thyroid hormone levels and with thyroid medication.

• Liver disease or a history of liver injury linked to supplements.

• Heart conditions or hyperandrogenism.

• Treatment with sedatives, anxiolytics or sleeping pills: possible additive effect.

• Immunosuppressive treatment or autoimmune disease: check with your specialist first.

• Scheduled surgery: stop taking it at least two weeks beforehand.

If you take any medication on a long-term basis, talk to your doctor or pharmacist before starting.

Which ashwagandha should you choose?

The quality of an ashwagandha extract is measured by its withanolides, the plant’s characteristic compounds. We’ve noticed that many consumers compare supplements purely on that percentage and go for the highest number. It’s a common mistake. Extracts that include leaf as well as root reach very high percentages, but the part that has been studied clinically, and that underpins the traditional use, is the root. A 5 % root-only extract is the benchmark with the most published trials; a 10 % root-and-leaf extract is not “twice as good”, it is a different, less researched profile.

By that standard, this is ours:

We chose KSM-66® because it is the raw material behind most of the published trials, with the same standardisation and root only: what was studied matches what is in the capsule. If you’re looking at other options for your wind-down routine, take a look at our Stress & Sleep collection.

Frequently asked questions about ashwagandha

Does ashwagandha make you gain or lose weight?
It is not a weight-management product and there is no evidence that it changes body weight on its own. What is worth knowing is that chronically high cortisol promotes abdominal fat storage and increases appetite, and it is one of the reasons many people under sustained stress struggle to lose weight even when they watch their diet. In the studies that measured it, participants taking ashwagandha showed lower cortisol levels than the placebo group. If stress is what’s holding you back, it is one more piece of the puzzle, never a substitute for diet and exercise.

Can I take ashwagandha with magnesium or melatonin?
Yes. No interactions have been described between them and it is a common combination. The sensible approach is ashwagandha in the morning and melatonin just before bed; magnesium bisglycinate fits either slot.

Can I take ashwagandha every day indefinitely?
No. Studies cover periods of up to 3 months and there are no long-term safety data. Take cycles of 8 to 12 weeks with breaks of 2 to 4 weeks, and review whether it still makes sense for you with a healthcare professional.