Ashwagandha (Withania somnifera) is increasingly included in strength-training routines. It is sometimes presented as a product that can quickly increase strength, testosterone or muscle mass. The available clinical trials are more nuanced: some observed greater training adaptations, but they tested specific extracts in small groups for only a few weeks.
For someone training in Morocco, the useful question is not “does ashwagandha build muscle?”, but “how much of the result came from training, what did the trials actually measure, and do their findings apply to the product I am considering?”. This guide answers those questions without making performance promises.
What the trials actually studied
The most relevant studies did not compare ashwagandha with doing no exercise. Participants followed a training programme and received either an ashwagandha extract or placebo. Both groups could therefore improve through resistance training; the question was whether the extract changed the size of that improvement.
That distinction is essential. Progress first depends on regular progressive training, suitable nutrition, sleep and recovery. None of these trials shows that ashwagandha builds muscle without those foundations or replaces a well-designed programme.
Strength and muscle size: an encouraging first trial
In the randomised trial published by Wankhede and colleagues in 2015, 57 young men with little resistance-training experience were assigned to a root extract or placebo, and 50 completed the eight weeks. Everyone followed the same programme. The ashwagandha group received 300 mg of a specific extract twice daily and showed larger average strength gains in the bench press and leg extension than placebo.
The researchers also measured the size of selected muscles, body fat, creatine kinase and testosterone, with several differences favouring supplementation. Caution is still needed: the final sample was small, participants were relatively untrained men, and the study lasted only eight weeks. It suggests a possibility; it cannot guarantee the same result in women, trained athletes or with another extract.
A second trial did not confirm everything
The STAR Trial published in 2018 followed 66 physically active men for twelve weeks. They received placebo, 250 mg or 500 mg per day of an aqueous root-and-leaf extract while following a four-day-per-week resistance programme. Maximum squat improvement was greater in the 500 mg group, with some favourable signals for power, muscular endurance and perceived recovery.
However, this trial found no statistically significant between-group difference in body composition. A signal in one strength measure does not automatically prove greater muscle mass or fat loss. Results were not uniform across outcomes.
Recovery: what do data in women show?
Women have long been underrepresented in this research. A controlled trial published in 2025 studied 30 female footballers aged 18 to 36 for 28 days. The ashwagandha group received 600 mg per day of a root extract and the control group received placebo. The trial observed improvements in overall perceived recovery and perceived sleep quality in the supplemented group.
This finding mainly concerns perception questionnaires, not demonstrated muscle growth. Strength measures did not show an equally clear overall benefit, and the analysis found that carbohydrate intake influenced several outcomes. It is a reminder that nutrition and training load may matter more than the supplement being studied.
Why trial doses are not a prescription
The cited trials used different extracts: root only or root-and-leaf, with different concentrations and extraction processes, at 250, 500 or 600 mg per day depending on the protocol. Two products displaying the same milligram number are therefore not necessarily equivalent. Plant part, withanolide standardisation and other ingredients should be checked on the label.
Those amounts describe research protocols; they are not personalised recommendations. For the product you actually buy, follow the labelled serving and do not increase it in an attempt to reproduce a study. Long-term safety remains insufficiently understood.
How to decide whether it fits your routine
Start by assessing the foundations: progressive programming, technique, adequate dietary protein and energy, hydration, sleep and recovery days. If one is missing, ashwagandha will not compensate for it. Define a measurable goal—such as performance on one lift or sleep consistency—instead of expecting a vague “boost”.
If you choose to use it, do not start several supplements at the same time. Record the date, exact product and tolerability, and stop if an adverse effect appears. An athlete subject to anti-doping testing should also prioritise documented traceability and contaminant testing: “natural” does not automatically mean free from prohibited substances.
Precautions to know before starting
NCCIH states that ashwagandha may cause drowsiness, stomach upset, diarrhoea or vomiting. Rare cases of liver injury have also been reported. It should be avoided during pregnancy and breastfeeding and is not recommended before surgery or in people with thyroid or autoimmune disorders without medical advice.
Interactions are possible with some medicines for diabetes or high blood pressure, immunosuppressants, sedatives, anti-seizure medicines and thyroid hormones. Read our detailed side-effects guide and show the complete label to a doctor or pharmacist if you take medication. A supplement does not replace diagnosis, suitable nutrition or prescribed treatment.
Bottom line
A few controlled trials suggest that certain ashwagandha extracts may accompany strength gains or some aspects of recovery when combined with structured training. However, study groups are modest, extracts are not interchangeable and findings for muscle mass are inconsistent.
The most honest interpretation is therefore “possible adjunct”, not “a product that builds muscle”. Put training, nutrition and sleep first, then assess product quality and your medical situation before supplementation.
Frequently asked questions
Does ashwagandha increase muscle mass?
A small trial in untrained men found differences in some muscle measurements, while another found no significant body-composition difference. Muscle gain therefore cannot be guaranteed. Training and nutrition remain decisive.
Is it a testosterone booster for strength training?
A mean testosterone increase was observed in one specific trial, but that does not diagnose or treat hormone deficiency or guarantee better performance. Hormonal symptoms require medical assessment, not self-treatment.
Should ashwagandha be taken before or after training?
Trials studied regular use over several weeks and do not show that taking it immediately before or after a workout is superior. Follow the product label and consider possible drowsiness.
Can it be combined with whey or creatine?
No known interaction in these trials does not prove that every combination suits everyone. Check complete ingredient lists, avoid duplication and seek professional advice if you take medication, have a chronic condition or develop an adverse effect.
Educational content: this is not a diagnosis or prescription and does not replace professional healthcare advice.
