The Claim

Withania somnifera supplementation at 300mg twice daily for 8 weeks significantly increases arm muscle cross-sectional area (8.9 cm², 95% CI: 7.0-10.8) compared to placebo (5.3 cm², 95% CI: 3.3-7.3, p=0.01) and chest circumference (3.3 cm, 95% CI: 2.6-4.1) compared to placebo (1.4 cm, 95% CI: 0.8-2.0, p<0.001) in healthy young untrained males undergoing resistance training.

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

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
1 study reviewed
In plain English

Taking ashwagandha supplements (300mg twice daily for 8 weeks) while doing weight training makes your arm muscles and chest grow bigger compared to just doing weight training with a fake pill (placebo).

See the scientific wording

Withania somnifera supplementation (300mg twice daily for 8 weeks) significantly increases arm muscle cross-sectional area by 8.9 cm² (95% CI: 7.0, 10.8) compared to 5.3 cm² (95% CI: 3.3, 7.3) in placebo (p=0.01) and chest circumference by 3.3 cm (95% CI: 2.6, 4.1) compared to 1.4 cm (95% CI: 0.8, 2.0) in placebo (p<0.001) in healthy young untrained males doing resistance training

What the research says

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

    This RCT directly compared muscle size changes between groups using standardized anthropometric measurements. The statistically significant differences in arm and chest measurements (but not thigh) demonstrate that ashwagandha enhances muscle hypertrophy, particularly in upper body muscle groups.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 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.