If you've researched ashwagandha, you've probably noticed that not all extracts look the same.

Some products contain traditional ashwagandha root powder. Others use concentrated root extracts or a combination of root and leaf. You may also come across branded extracts such as KSM-66®, which use specific extraction and standardisation methods.

So, what's actually the difference?

Understanding the part of the plant used, the concentration of active compounds, the extraction process and the clinical research behind an extract can help explain why two ashwagandha ingredients with similar-looking labels may be quite different.

What Is Ashwagandha?

Ashwagandha (Withania somnifera) is a plant with a long history of use in Ayurveda, the traditional medicine system of India.

It is often described as an adaptogen, a term used for certain herbs traditionally associated with the body's response to physical and mental stress.

Modern research has investigated ashwagandha in areas including:

• Stress and perceived stress
• Cortisol
• Sleep
• Physical performance
• Muscle strength
• Cognitive function
• General wellbeing

However, research findings cannot necessarily be applied equally to every ashwagandha ingredient.

Different studies may use different plant parts, extraction methods, concentrations and doses. This makes the type of extract an important consideration when interpreting the evidence.

Not All Ashwagandha Extracts Are the Same

Ashwagandha is available in several different forms, each with its own characteristics.

1. Raw Ashwagandha Root Powder

Traditional ashwagandha preparations commonly use the dried root of the plant.

Root powder is produced by drying and grinding the root rather than creating a concentrated extract.

Potential characteristics include:

• Minimal processing
• Traditional use of the root
• Lower concentration of withanolides compared with concentrated extracts
• Greater natural variation in phytochemical composition

Because root powder is not necessarily standardised, the concentration of naturally occurring compounds can vary between ingredients and batches.

This means two ingredients providing the same number of milligrams of ashwagandha root powder may not necessarily provide identical phytochemical profiles.

2. Standardised Root Extracts

Ashwagandha root can also be processed into a concentrated extract.

Standardisation allows manufacturers to produce an ingredient containing a specified concentration of particular naturally occurring constituents, commonly withanolides.

However, not all standardised extracts are identical.

They may differ according to:

• Withanolide concentration
• Extraction method
• Raw material
• Plant source
• Manufacturing processes
• Standardisation method

For this reason, looking only at the number of milligrams on a label doesn't provide a complete picture of an extract.

3. Root and Leaf Extracts

Some ashwagandha extracts contain both the root and leaves of the plant.

The leaves naturally contain different concentrations and proportions of withanolides compared with the root, including compounds such as withaferin A.

Using both plant parts can therefore produce a phytochemical profile that differs from a root-only extract.

This doesn't automatically make one approach better than another. Instead, it means research conducted using one specific extract shouldn't necessarily be assumed to apply to another extract with a different composition.

What Are Withanolides?

Withanolides are a group of naturally occurring steroidal lactones found in Withania somnifera.

They are among the major bioactive compounds researchers investigate when studying ashwagandha.

The concentration of withanolides is often displayed as a percentage. For example, an extract standardised to 5% withanolides is manufactured to provide a consistent concentration of these compounds.

However, a higher percentage doesn't automatically mean a better or more effective ashwagandha extract.

The overall phytochemical composition, plant part, extraction process, dose and evidence supporting the specific extract all need to be considered when interpreting research.

What Is KSM-66® Ashwagandha?

KSM-66® is a branded, standardised ashwagandha extract produced exclusively from the root of Withania somnifera.

Some of its distinguishing characteristics include:

• 100% root-derived extract
• Standardisation to at least 5% withanolides
• A proprietary extraction process
• No use of ashwagandha leaves
• A substantial body of human clinical research using the specific extract

KSM-66 is described as a "full-spectrum" extract because its manufacturing process is designed to maintain a range of naturally occurring constituents from the root rather than isolating a single compound.

Importantly, KSM-66 is not simply another name for ashwagandha.

It is one specific ashwagandha ingredient with defined manufacturing and standardisation characteristics.

Why Does Root-Only Ashwagandha Matter?

One of the primary differences between KSM-66 and some other concentrated ashwagandha extracts is the use of the root without the leaves.

There are several reasons this distinction is relevant.

Traditional Use

The root has an established history of use within traditional Ayurvedic practice.

Modern root-only extracts draw on this traditional use while using contemporary extraction and standardisation techniques to create a more consistent ingredient.

However, traditional use and modern clinical evidence are not the same thing, and each needs to be considered separately when evaluating an ingredient.

Different Phytochemical Profiles

The root and leaves of ashwagandha contain different proportions of naturally occurring compounds.

Leaves generally contain higher concentrations of certain withanolides, including withaferin A, while the root has its own characteristic phytochemical profile.

As a result, root-only and root-plus-leaf extracts are chemically different even though both come from the same plant.

Research Is Extract-Specific

This is perhaps the most important distinction.

Clinical research on botanical ingredients is generally conducted using a specific extract at a specific dose.

If a study investigates KSM-66, for example, the findings relate to the KSM-66 extract used in that study. They cannot automatically be applied to every product containing ashwagandha.

This principle applies equally to other branded and standardised extracts.

What Has KSM-66 Been Studied For?

KSM-66 has been evaluated in human clinical trials across several areas.

Research has investigated its potential relationship with:

• Perceived stress
• Cortisol levels
• Sleep
• Physical performance
• Muscle strength and recovery
• Cognitive performance
• Sexual wellbeing

One frequently cited randomised, double-blind, placebo-controlled trial investigated a high-concentration full-spectrum ashwagandha root extract in adults experiencing stress. Researchers reported differences between the ashwagandha and placebo groups in measures including perceived stress and serum cortisol.

Other trials have investigated different outcomes and populations.

However, individual studies should not be interpreted as proof that ashwagandha will produce the same effects in everyone. Study size, duration, participant characteristics and methodology all influence how findings should be interpreted.

Research into ashwagandha continues to evolve.

KSM-66® vs Other Ashwagandha Extracts

The key takeaway from this comparison isn't that one form is automatically "best."

Instead, it highlights why simply comparing the number of milligrams or total withanolide percentage doesn't tell you everything about an ashwagandha extract.

What Should You Look at When Comparing Ashwagandha Research?

When reading about ashwagandha, consider:

Which part of the plant was used?

Check whether the study used the root, leaves or a combination.

Was the extract standardised?

Standardisation can help ensure a more consistent concentration of particular phytochemicals.

What specific extract was studied?

Research involving one branded or standardised extract cannot automatically be generalised to every ashwagandha ingredient.

What dose was investigated?

Botanical research is dose-specific. A study using one dose doesn't necessarily provide evidence for a substantially different dose.

Who participated in the study?

Results observed in healthy adults, athletes or people experiencing stress may not necessarily apply to other populations.

What outcome was actually measured?

A study examining perceived stress does not automatically provide evidence for sleep, cognition or another health outcome.

Looking at these details provides a much clearer understanding of what the research actually shows.

The Bottom Line

Not all ashwagandha extracts are the same.

Root powder, concentrated root extracts and root-plus-leaf extracts can differ substantially in their phytochemical composition, standardisation and manufacturing processes.

KSM-66® is distinguished by its use of 100% ashwagandha root, defined standardisation and the number of human clinical studies that have investigated the specific extract.

That doesn't mean every root-only extract is inherently superior to every root-plus-leaf extract. Instead, it highlights an important principle when evaluating botanical research: the evidence for a specific extract should not automatically be applied to every ingredient made from the same plant.

Rather than focusing solely on milligrams or withanolide percentage, understanding the plant part, extraction method, standardisation and research behind an ingredient provides a more complete picture of how different ashwagandha extracts compare.

References

1. Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomised double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian Journal of Psychological Medicine. 2012;34(3):255-262.
2. National Institutes of Health, Office of Dietary Supplements. Ashwagandha: Is It Helpful for Stress, Anxiety, or Sleep?
3. Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomised, double-blind, placebo-controlled study. Medicine. 2019;98(37):e17186.
4. Langade D, Kanchi S, Salve J, Debnath K, Ambegaokar D. Efficacy and safety of ashwagandha (Withania somnifera) root extract in insomnia and anxiety: A double-blind, randomised, placebo-controlled study. Cureus. 2019;11(9):e5797.
5. Wankhede S, Langade D, Joshi K, Sinha SR, Bhattacharyya S. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: A randomised controlled trial. Journal of the International Society of Sports Nutrition. 2015;12:43.