StrengthNCT07890935
Effects of Root Extract Ashwagandha (KSM-66) on Perception of Recovery and Muscle Strength in Adolescents Aged 11 to 19 Engaged in Grassroots Football
A study testing Ashwagandha in people with Strength and Stress, run by Sports Performance and Applied Research in Trials and Analysis.
Trial summary
This study will test whether six weeks of ashwagandha (KSM-66 root extract), helps teenage footballers recover and improve strength. Very little research has looked at young people aged 11 to 19, despite increased usage in this cohort. Read more about this study
- Who is it for?
- Ages 11 to 19 yearsHealthy volunteers can take part
- Conditions the study is for
- Strength, Stress, Exercise Adaptation
- What is being tested?
- Ashwagandha
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 60 participants
- Where
- No sites listed yet
- Study dates
- 1 Nov 2026to 20 Dec 2026
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 11 to 19 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- Aged 11 to 19 years on the day of baseline testing
- Male or female player registered with a participating grassroots football club or community football programme, taking part in organised football training at least once a week (any playing ability)
- Able to attend both testing sessions and able to swallow a capsule
- Valid written consent: parent/caregiver consent and player assent (ages 11 to 15), or the player's own consent (ages 18 to 19)
Who cannot join
- Diagnosed liver, kidney or thyroid condition
- Autoimmune condition (e.g. type 1 diabetes, lupus, rheumatoid or juvenile idiopathic arthritis, inflammatory bowel disease)
- Diabetes or another condition affecting blood sugar; high or low blood pressure requiring treatment
- Regularly takeing prescribed medicine
- Known allergy or intolerance to ashwagandha, nightshade family plants, corn (maize) or the capsule shell
- Pregnant, possibly pregnant or breastfeeding
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- Stomach ulcer; heart condition; chest pain, fainting or seizures during exercise; or medical advice not to do hard exercise
- Current illness or injury that prevents maximal effort
- Surgery planned during the study or within 2 weeks after it, or hospital admission in the last 3 months
- Currently taking, or taken in the past 4 weeks, ashwagandha in any form, including combination products
- Unwilling to avoid starting any new supplement during the six weeks
- Taking part in another research study involving a supplement or medicine in the past 3 months
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
Olivia C Coope, PhD(c) contact
About this study
Official title: Effects of KSM-66 Ashwagandha (Withania Somnifera) Root Extract Supplementation on Perception of Recovery and Muscle Strength in Adolescents in Grassroots Football: A Randomised, Double-Blind, Placebo-Controlled Trial
This study will test whether six weeks of ashwagandha (KSM-66 root extract), helps teenage footballers recover and improve strength. Very little research has looked at young people aged 11 to 19, despite increased usage in this cohort.
About 50 to 60 male and female players from grassroots clubs in Sussex, Surrey and Greater London will be randomly assigned to take a daily capsule of either 450 mg ashwagandha or a placebo in an unblinded fashion. Before and after the six weeks, players will do tests at their usual training site: saliva samples to measure the cortisol, grip strength, a 1 km time trial, and short questionnaires on recovery, sleep, stress and soreness.
The results will show whether ashwagandha changes stress, strength, performance and perceived recovery over six weeks.
Read the detailed description
This randomised, double-blind, placebo-controlled trial will test whether KSM-66 ashwagandha (Withania somnifera) root extract alters physiological stress, neuromuscular performance and perceived recovery in adolescent footballers. In adults, standardised root extract has been associated with improved strength, recovery, sleep and reduced cortisol. In children, the only placebo-controlled trial of root extract (ages 6 to 12) examined cognition and sleep. No trial has studied adolescents, whose growth, maturation and training load may alter responses, so adult findings cannot be assumed to apply.
An independent collaborator outside the research team will generate the allocation (block size four, stratified by sex and age band, 11 to 15 and 16 to 19) and label bottles with participant codes only. Participants, caregivers and investigators will remain blind until the dataset is locked, and blinding success will be assessed at follow-up. Players aged 11 to 15 take part with parental consent and their own assent, and players aged 16 to 19 consent for themselves. A study medical official will screen medical eligibility. Caregivers or participants will be contacted weekly regarding adverse events, and any suspected supplement-related event will lead to discontinuation and medical review within 24 hours.
Data will be analysed by linear mixed methods. Two investigators will analyse the coded data independently and blind to allocation. Results will be interpreted as short-term responses and will not establish long-term safety or efficacy.
- Conditions
- Strength, Stress, Exercise Adaptation, Sleep, Recovery After Exercise
- Being tested
- Ashwagandha, Placebo
- Keywords
- Ashwagandha
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AshwagandhaDietary supplement
Also called KSM-66
One 450 mg capsule of KSM-66 ashwagandha, taken once daily with a meal for six weeks (42 days). KSM-66 is a full-spectrum extract made from root only, with no leaf, standardised to 5% withanolides (HPLC verified), and supplied with a certificate of analysis for each batch. Capsules are supplied in labelled bottles of 42 and are identical in appearance to the placebo.
PlaceboDietary supplement
One 450 mg capsule of corn starch, taken once daily with a meal for six weeks (42 days). The capsule shell, appearance, bottle and labelling are identical to the active capsule.
| Study group | Role | What they receive |
|---|---|---|
| Root extract Ashwagandha | Experimental | 450mg of KSM-66 Ashwagandha Receives: Dietary Supplement: Ashwagandha |
| Placebo | Placebo comparator | 450mg corn starch Receives: Dietary Supplement: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Salivary cortisol
Saliva collected with Salivette tubes after an evening training session and analysed by an external laboratory. Reported as the change from baseline to follow-up.
Measured: Baseline (week 0) and after six weeks of supplementation
Secondary outcomes (5)
Salivary alpha-amylase
Measured from the same saliva samples as cortisol.
Measured: Baseline (week 0) and after six weeks of supplementation
Handgrip Strength
Maximal handgrip strength measured with a CAMRY handgrip dynamometer.
Measured: Baseline (week 0) and after six weeks of supplementation
Number of participants with adverse events
Any adverse events reported in the duration of the clinical trial
Measured: Baseline (week 0) and after six weeks of supplementation
Change in perceived recovery, measured by the Hooper Index
Self-reported fatigue, stress, sleep quality and muscle soreness on the Hooper Index questionnaire. Individual items are scored 1 (very, very good) to 10 (very, very bad) and the total score is 4 to 40, higher scores indicating poorer recovery.
Measured: Baseline (week 0) and after six weeks of supplementation
Change in 1 km time-trial performance
Time taken to complete a 1 km run, as a measure of aerobic fitness and high-intensity running capacity.
Measured: Baseline (week 0) and after six weeks of supplementation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Oct 2026
- Study start1 Nov 2026 (estimated)
- Primary completion20 Dec 2026 (estimated)
- Study completion20 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for StrengthStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sports Performance and Applied Research in Trials and Analysis
- Sponsor type
- Research network
- Responsible party
- Principal investigator, Alex Levington, Sports Performance and Applied Research in Trials and Analysis
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07890935
- Sponsor's protocol ID
- ASH-ADOL-001
- Status last verified
- Oct 2026
- First submitted
- 14 Oct 2026
- Last updated
- 22 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared. Participants will be minors recruited from a small number of local football clubs, so a dataset of this size (about 50 to 60 players) combined with age, sex and test results could allow re-identification even after coding. Consent and assent were obtained for use of the data within this study only, and the participant code key and contact details will be permanently deleted on 31 May 2027. The fully anonymised dataset will be held securely by the research team and used only for the analyses and publications described in the ethics-approved protocol. Summary results will be reported in the results section of this record and in peer-reviewed publication, with participating clubs not named.