The Claim

Ashwagandha (Withania somnifera) standardized extract KSM-66, when administered at a dosage of 300-600mg daily for a duration of 8 weeks, produces effects on strength, endurance, and cortisol levels in human subjects.

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
68score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
2 studies reviewed
In plain English

Taking a specific ashwagandha supplement called KSM-66 at 300-600mg every day for about 2 months can change how strong you are, how long you can exercise, and your stress hormone levels.

See the scientific wording

The effects of ashwagandha on strength, endurance, and cortisol require specific conditions including use of standardized extract (KSM-66), dosage of 300-600mg daily, and duration of 8 weeks

What the research says

2 studies

  1. Study: Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial

    This study tested ashwagandha (600mg daily for 8 weeks) and found it improved muscle strength in people doing resistance training. This matches part of the claim about dosage and duration, but the study didn't test cortisol or endurance, and didn't specify using KSM-66 extract. The study supports the claim partially but doesn't cover all the conditions mentioned.

  2. Study: Effects of Ashwagandha ( Withania somnifera) standardized root extract on physical endurance and VO 2max in healthy adults performing resistance training: An eight-week, prospective, randomized, double-blind, placebo-controlled study

    This study tested ashwagandha at 600mg daily for 8 weeks and found it improved strength and endurance in people doing resistance training. This matches most of the claim's conditions (dosage within 300-600mg range, 8 weeks duration), though it doesn't specifically mention KSM-66 extract or measure cortisol as the claim states.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 2 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.