Ashwagandha is one of the most widely used herbs in the world, yet it is also one of the most misunderstood. Many products focus on headline numbers, extract strength or withanolide percentages without explaining what those figures actually mean, or how they relate to traditional use and modern research. As a result, two ashwagandha supplements that look similar on paper can behave very differently in the body.
This guide explains what ashwagandha is, why the root matters, what withanolides actually are, and why concentration is not as simple as “higher equals better”. It also sets out what distinguishes KSM-66, a root-only, full-spectrum extract, from many other forms of ashwagandha on the market.
Topics We Will Cover:
1. What Is Ashwagandha?
2. Ashwagandha Root vs Leaf: Why Source Matters
3. What Are Withanolides?
4. Understanding Ashwagandha Concentration and Standardisation
5. What Makes KSM-66 Different?
6. Why Root-Only, Full-Spectrum Matters Biologically
7. Organic Ashwagandha: Why Growing Conditions Matter
8. How Ashwagandha Works in the Body
9. What Does “Adaptogen” Mean?
10. What Ashwagandha Can and Cannot Do
11. How Long Ashwagandha Takes to Show Effects
12. How to Take Ashwagandha Capsules
13. Safety, Tolerance and Who Should Seek Advice
14. Why Choose VitaBright Ashwagandha (KSM-66)?
15. Further Reading
1. What Is Ashwagandha?
Ashwagandha (Withania somnifera) is a small shrub native to India, the Middle East and parts of Africa. It has been used for centuries in Ayurvedic medicine, where the root was traditionally prepared as a powder or decoction and taken over long periods rather than as a short-term remedy.
Historically, ashwagandha was valued for its ability to support resilience during periods of physical or mental strain. This long-term, supportive use is an important part of understanding how the herb is intended to work - it’s neither a sedative nor a stimulant, but intended to help the body re-establish natural sleeping patterns and sustained energy, restoring the body’s balance.
Modern supplements differ from traditional preparations in one key way: they concentrate the compounds found in the plant. This makes dosage more consistent and convenient, but it also means that sourcing, extraction method and plant part used become critically important. Without this context, labels and percentages can be misleading.
2. Ashwagandha Root vs Leaf: Why Source Matters
Traditionally, ashwagandha preparations used the root, not the leaves. This distinction matters because different parts of the plant produce different profiles of active compounds.
Ashwagandha leaves contain higher concentrations of certain withanolides, particularly withaferin A. While this can increase the total withanolide percentage on a label, it also changes how the extract behaves biologically. Leaf-derived withanolides are more stimulating and can be less well tolerated by some people, particularly at higher concentrations.
Root-only extracts, by contrast, provide a broader and more balanced spectrum of compounds closer to traditional use. The withanolides found in the root tend to be present in lower individual concentrations but in a more complex mix, which appears to influence how the herb interacts with stress-response and nervous system pathways.
Some modern extracts include leaves to boost potency figures or reduce production costs. This does not make them inherently unsafe, but it does make them different and less suitable for people seeking relief from stress or feelings of agitation. For people looking to mirror traditional use and prioritise tolerance and long-term use, root-only extracts are generally preferred.
KSM-66 is made exclusively from the root, which is a defining feature of the extract.
3. What Are Withanolides?
Withanolides are a group of naturally occurring compounds found in ashwagandha. They are often described as the plant’s main “active ingredients”, but this can be misleading. Withanolides are not a single substance; they are a family of related compounds, each with slightly different biological effects.
The total withanolide percentage listed on a supplement label reflects the combined amount of these compounds, not their individual balance or origin within the plant. This is why two products with the same withanolide percentage can behave very differently in practice.
Importantly, the type and ratio of withanolides matters, not just the total amount. Root-derived withanolides differ from leaf-derived withanolides, and full-spectrum extracts behave differently from isolates or heavily concentrated fractions. Traditional preparations relied on the natural balance found in the root rather than maximising one compound in isolation.
Understanding withanolides in this way helps explain why higher numbers do not automatically mean a better or more appropriate ashwagandha supplement, and why extraction method and plant part matter as much as headline potency.
4. Understanding Ashwagandha Concentration and Standardisation
One of the most common sources of confusion with ashwagandha supplements is the idea of “strength”. Labels often highlight extract ratios, such as 5:1 or 10:1, or focus heavily on withanolide percentages. On their own, these figures do not tell you how an extract will behave in the body.
An extract ratio simply describes how much raw plant material was used to produce the extract. A 10:1 extract means ten parts of plant were concentrated into one part of extract, but it does not indicate which compounds were retained, lost or altered during processing. A higher ratio does not automatically mean a better or more effective product.
Withanolide standardisation adds another layer. When an extract is standardised to a certain percentage of withanolides, it means the manufacturer has adjusted the extract so that each batch contains a consistent total amount of these compounds. However, this total figure does not show which withanolides are present, whether they come from root or leaf, or how balanced the final profile is.
This is why two ashwagandha products with the same withanolide percentage can feel very different when taken. Concentration alone does not determine suitability, tolerance or long-term use. The source of the compounds and how they are extracted matter just as much as the numbers on the label.
5. What Makes KSM-66 Different?
KSM-66 is a branded ashwagandha extract developed specifically to address these issues. It is made using only the root of the ashwagandha plant and is designed to preserve a broad, natural spectrum of root-derived compounds rather than isolating or amplifying individual withanolides.
The extraction process uses gentle, food-grade methods rather than harsh chemical solvents. This helps retain compounds that are lost in more aggressive extraction techniques and supports a profile closer to traditional root preparations, while still providing the consistency expected of a modern supplement.
KSM-66 is also extensively studied in human research, with trials typically using doses that reflect real-world supplementation rather than extreme concentrations. This makes the research more relevant to everyday use and helps explain why KSM-66 is often associated with good tolerance over longer periods.
Rather than aiming for the highest possible withanolide percentage, KSM-66 prioritises balance, reproducibility and root integrity.
6. Why Root-Only, Full-Spectrum Matters Biologically
Plants do not work through single compounds in isolation. In ashwagandha root, withanolides coexist with other naturally occurring substances that influence how they are absorbed, distributed and metabolised.
A full-spectrum, root-only extract reflects this complexity. Instead of delivering a narrow, intensified signal to the body, it provides a broader range of inputs that interact more subtly with stress-response and nervous system pathways. This may help explain why root-only extracts are often described as supporting adaptation and resilience rather than producing sharp or immediate effects.
Isolated or leaf-heavy extracts, by contrast, can shift this balance. Higher levels of certain withanolides may increase potency on paper but can also increase the likelihood of unwanted stimulation or poor tolerance in some people, particularly when taken daily.
Root-only, full-spectrum extracts are therefore generally chosen when the goal is steady, long-term support rather than short-term intensity.
7. Organic Ashwagandha: Why Growing Conditions Matter
Ashwagandha is a root crop, which means it grows in direct contact with soil for long periods. This makes growing conditions especially important. Roots can absorb substances from the soil, including pesticides, heavy metals and other contaminants, if they are present.
Organic cultivation reduces the risk of pesticide residues and places greater emphasis on soil health and crop management. This matters not only for safety, but also for consistency. Plants grown in healthier soils tend to produce more stable and predictable phytochemical profiles.
Using organically grown ashwagandha also aligns with the way the plant has traditionally been cultivated and harvested. When combined with careful extraction and testing, organic sourcing adds another layer of confidence that what you are taking reflects both traditional practice and modern quality standards.
8. How Ashwagandha Works in the Body
Ashwagandha does not act like a stimulant, sedative or hormone. Instead, research suggests it interacts with systems involved in how the body responds to stress, particularly the hypothalamic–pituitary–adrenal (HPA) axis, which regulates cortisol and other stress-related signals.
Studies using root-only ashwagandha extracts, including KSM-66, have repeatedly reported effects on cortisol levels in people experiencing ongoing psychological stress. These are typically randomised, placebo-controlled human trials lasting between eight and twelve weeks. Across these studies, cortisol reductions tend to be modest and gradual rather than dramatic. Importantly, they are observed primarily in people with elevated stress levels at baseline, not in unstressed populations. This suggests that ashwagandha does not suppress cortisol indiscriminately, but may influence how cortisol is regulated when stress signalling remains chronically activated.
Sources for reduced cortisol and anxiety:
Current evidence points towards an effect on the hypothalamic–pituitary–adrenal (HPA) axis, which governs the body’s stress response. Under prolonged stress, signalling between the hypothalamus, pituitary gland and adrenal glands can become overactive, leading to cortisol remaining elevated for longer than is biologically useful. Ashwagandha does not appear to block cortisol production directly. Instead, researchers propose that it may support more appropriate feedback within this system, allowing cortisol levels to rise in response to stress and then fall back more efficiently once the stressor has passed.
There is also evidence that ashwagandha influences nervous system signalling, particularly pathways involving gamma-aminobutyric acid (GABA). GABA is the primary inhibitory neurotransmitter in the brain and plays a key role in regulating excitability and stress reactivity. Ashwagandha does not act as a sedative, but it appears to support inhibitory tone in stress-related neural circuits. By reducing excessive neural firing associated with chronic stress, it may lower the intensity of stress signals reaching the HPA axis, indirectly influencing cortisol output.
This combination of effects helps explain why ashwagandha is often described as supporting resilience rather than producing an immediate sensation. People do not typically feel a sudden calming effect after taking it. Instead, reported changes tend to relate to how strongly or persistently stress responses are experienced over time. This aligns with the gradual changes seen in cortisol measurements and stress questionnaires used in clinical studies.
There are still important gaps in the evidence. Researchers have not identified a single molecular target responsible for these effects, and most studies involve relatively small participant numbers. It is also not clear whether similar effects occur in people without elevated stress or cortisol levels. For this reason, ashwagandha is best described as supporting stress regulation in specific contexts rather than as a universal stress-lowering agent. The current evidence supports a role in modulating stress responses over time, not in overriding normal physiology or producing rapid changes.
So far, researchers have also made early discoveries that seem to confirm traditional uses of Ashwagandha for better mental focus and cognitive function (Acute and Repeated Ashwagandha Supplementation Improves Markers of Cognitive Function and Mood’ by Leonard at al.) and for improved physical stamina and resilience (Examining the effect of Withania somnifera supplementation on muscle strength and recovery: A randomized controlled trial).
9. What Does “Adaptogen” Mean?
The term adaptogen is often used to describe herbs like ashwagandha, but it is rarely explained clearly. The word was first introduced in the late 1940s by Russian scientist Nikolai Lazarev, who used it to describe substances that increased the body’s general resistance to stress. Later researchers, including Brekhman and Dardymov in the 1960s, proposed criteria for adaptogens: they should be non-toxic at normal doses, support overall resistance to stress, and help normalise physiological function rather than push it in one direction.
In practical terms, adaptogen is not a medical term or a regulatory category of medication. It is a descriptive concept used in research and traditional medicine to group substances that appear to influence how the body adapts to physical, mental or environmental stress.
Modern doctors and regulators do not tend to use the term “adaptogen”. It is not used in clinical medicine, and it does not imply that a substance treats or prevents disease. However, the underlying idea of supporting regulatory systems rather than forcing a specific outcome, is consistent with how researchers currently describe the effects of ashwagandha in human studies.
Understanding this helps avoid misunderstanding. When ashwagandha is described as an adaptogen, it does not mean it “balances everything” or works the same way for everyone. It means it appears to interact with stress-response systems in a way that supports regulation rather than stimulation or suppression.
10. What Ashwagandha Can and Cannot Do
Ashwagandha supplements do not act like medicines. They do not produce immediate calming effects, override stress responses, or correct underlying medical conditions. They also do not replace treatment for anxiety disorders, depression, hormonal conditions or sleep disorders.
What evidence supports is a supportive role over time. In clinical studies, consistent use of root-only ashwagandha extracts has been associated with changes in stress markers, perceived stress scores and measures of wellbeing in some people, particularly those experiencing sustained stress.
Response varies. Factors such as baseline stress levels, sleep, diet, workload and individual sensitivity all influence outcomes. Some people notice subtle changes after several weeks, while others notice little effect.
For this reason, ashwagandha is best viewed as part of a broader approach that includes rest, nutrition and realistic expectations. Its role is supportive and gradual, not corrective or fast-acting.
11. How Long Ashwagandha Takes to Show Effects
Ashwagandha does not work immediately. Studies on root-only extracts such as KSM-66 typically assess outcomes over six to twelve weeks, which reflects how long it takes for stress-response systems to adjust rather than how quickly a substance is absorbed.
Some people notice subtle changes after a few weeks, such as feeling better able to cope with ongoing demands or less reactive to everyday stressors. For others, changes are slower or less noticeable. This variation is normal and reflects differences in baseline stress levels, sleep quality, workload and individual physiology.
Taking ashwagandha inconsistently makes it harder to assess whether it is helpful. Regular daily use over several weeks is more relevant than increasing the dose or expecting a short-term effect.
12. How to Take Ashwagandha Capsules
Ashwagandha capsules are typically taken once or twice daily, depending on the dose and formulation. Many people choose to take them with food to reduce the chance of stomach upset, although this is not essential for absorption.
Timing can be flexible. Some people prefer taking ashwagandha earlier in the day to support daytime stress resilience, while others take it in the evening as part of a wind-down routine. Because ashwagandha does not act as a sedative or stimulant, the best timing often comes down to personal preference.
Consistency matters more than timing. Taking the capsules at roughly the same time each day helps maintain steady exposure and makes it easier to assess your response over time.
13. Safety, Tolerance and Who Should Seek Advice
Root-only ashwagandha extracts such as KSM-66 are generally well tolerated when used at recommended doses. Most people experience no side effects, particularly when the extract is taken consistently rather than intermittently.
Ashwagandha is not suitable for pregnant women, as its effects during pregnancy have not been adequately studied. Breastfeeding women should also seek professional advice before use.
People with thyroid conditions should speak to a doctor or pharmacist before taking ashwagandha, as it may influence thyroid hormone levels in some cases. The same applies to people with autoimmune conditions or those taking medication that affects the immune system.
As with any supplement, if you are under medical care or taking prescribed medication, it is sensible to check with a healthcare professional before starting ashwagandha. This ensures it fits appropriately with your individual health circumstances.
14. Why Choose VitaBright Ashwagandha (KSM-66)?
VitaBright Ashwagandha Capsules use KSM-66, a well-established, root-only ashwagandha extract chosen for its balance, consistency and research base. The extract is made exclusively from the ashwagandha root, reflecting traditional use and avoiding the altered compound profiles that can result from leaf inclusion.
The ashwagandha used in KSM-66 is organically grown, which matters because ashwagandha is a root crop that remains in direct contact with soil for long periods. Organic cultivation reduces exposure to pesticide residues and supports more consistent growing conditions, contributing to a cleaner and more predictable extract.
We include no unnecessary additives. The capsules contain the extract itself and a plant-based capsule shell, keeping the formulation simple and suitable for vegetarian and vegan diets.
All VitaBright supplements are produced in state-of-the-art UK manufacturing facilities that hold BRC Grade AA accreditation, one of the highest standards available for supplement production. This means supplements are made in tightly controlled environments with strict hygiene, traceability and quality systems in place.
We manufacture to GMP standards, the same framework used for pharmaceutical medicines. Each batch follows documented processes, is produced under controlled conditions and is checked before release, helping ensure consistent quality from one bottle to the next.
Ingredients are sourced from carefully selected suppliers and verified before use. To protect purity, we arrange independent testing where appropriate. Every bottle is double sealed, so you can be confident it has not been opened or tampered with before it reaches you. We believe in our products and offer a money-back guarantee on everything we sell.
Alongside manufacturing standards, we provide clear product information and ongoing customer support. While we do not employ doctors, we are always happy to answer questions about our supplements within the limits of our expertise and help you make informed decisions.
15. Further Reading
Browse our blog posts on Ashwagandha
How to Take Ashwagandha for Stress, Sleep, and Energy — The Complete Guide
What Does Ashwagandha Do to the Body, and Is It Safe to Take?
Browse our blog posts on natural remedies for calm and mood regulation
