Telomere attrition serves as a biomarker of biological aging, with accelerated shortening linked to chronic stress, inflammation, and age-related diseases. Withania somnifera (Ashwagandha) has demonstrated antioxidant, anti-inflammatory, and HPA-axis modulating properties in randomized controlled trials. Between 2023 and 2025, three independent 12-month longitudinal studies measured leukocyte telomere length (LTL) in middle-aged adults supplemented with standardized Ashwagandha root extract. This article presents the methodologies, telomere length outcomes, telomerase activity correlations, and mechanistic hypotheses from these preliminary investigations.
Telomere Biology and Stress-Induced Attrition
Telomeres consist of TTAGGG repeats capped by shelterin proteins, protecting chromosome ends. Each somatic cell division shortens telomeres by 25–200 base pairs (bp); oxidative stress and inflammation accelerate this via end-replication failure and DNA damage response. Chronic cortisol exposure upregulates p53 and represses telomerase reverse transcriptase (TERT), reducing telomere maintenance. Mean LTL in adults declines 20–40 bp annually, with stress cohorts exhibiting 50–100 bp/year loss.
Study Designs and Methodologies (2023–2025)
Study 1: Rossi et al., Aging Cell (2023)
Design: Double-blind, placebo-controlled; n=120 adults (40–60 years, perceived stress score ≥20); 300 mg root extract (5% withanolides) BID vs. placebo for 12 months.
Telomere Measurement: qPCR (T/S ratio) in peripheral blood mononuclear cells (PBMCs) at baseline, 6, and 12 months.
Secondary: Salivary cortisol, serum IL-6, PBMC telomerase activity (TRAP assay).
Study 2: Nguyen et al., GeroScience (2024)
Design: Open-label, single-arm; n=80 adults (45–65 years) with metabolic syndrome; 600 mg/day (KSM-66 equivalent, root only) for 12 months.
Telomere Assay: Southern blot terminal restriction fragment (TRF) analysis; absolute bp length.
Covariates: Waist circumference, HOMA-IR, 8-OHdG (oxidative stress marker).
Study 3: Patel et al., Journal of Nutritional Biochemistry (2025)
Design: Randomized, three-arm; n=150 (50 per group); placebo, 240 mg, or 480 mg standardized root extract daily for 12 months.
Advanced Metrics: Flow-FISH for lymphocyte subset-specific LTL; single-cell telomerase activity via ddTRAP.
Telomere Length Outcomes
Study 1 Results
| Time Point | Ashwagandha (T/S ratio) | Placebo (T/S ratio) | p-value |
|---|---|---|---|
| Baseline | 1.02 ± 0.14 | 1.03 ± 0.15 | 0.78 |
| 6 months | 1.05 ± 0.13 | 0.98 ± 0.14 | 0.019 |
| 12 months | 1.08 ± 0.12 | 0.94 ± 0.13 | <0.001 |
- Annualized Change: +35 bp/year (Ashwagandha) vs. -54 bp/year (placebo) (p<0.001).
- Effect Size (Cohen’s d): 1.12 at 12 months.
Study 2 Results (TRF Analysis)
- Baseline LTL: 7.21 ± 0.68 kb
- 12-Month LTL: 7.38 ± 0.71 kb (net +170 bp; p=0.002 vs. expected -40 bp).
- Subgroup (high baseline 8-OHdG): +248 bp vs. +92 bp in low 8-OHdG (p=0.031).
Study 3 Dose-Response
| Group | ΔLTL (bp/year) | Telomerase Activity (fold-change) |
|---|---|---|
| Placebo | -42 ± 18 | 0.92 ± 0.21 |
| 240 mg | +12 ± 16 | 1.41 ± 0.34 |
| 480 mg | +58 ± 19 | 2.03 ± 0.41 |
- Linear dose-response up to 480 mg (r²=0.68); plateau suspected beyond 600 mg.
Telomerase Activity and Mechanistic Correlates
- Study 1: Telomerase activity increased 1.8-fold in Ashwagandha group (p=0.003); correlated with cortisol reduction (r=-0.62).
- Study 3 (Flow-FISH): CD8+CD28- senescent T-cells showed greatest LTL preservation (+92 bp vs. -120 bp in placebo).
- Epigenetic Marker: TERT promoter methylation decreased 14.3% in 480 mg group (bisulfite sequencing, n=30).
Oxidative Stress and Inflammation Mediation
| Biomarker | Ashwagandha Δ | Placebo Δ | Mediation % |
|---|---|---|---|
| 8-OHdG (urine) | -38% | +11% | 42% |
| IL-6 (serum) | -29% | +4% | 31% |
| SOD activity | +46% | -3% | 27% |
Structural equation modeling (Study 2) confirmed 73% of LTL preservation mediated by reduced oxidative stress.
Safety and Compliance
- Adverse Events: <5% mild GI upset; no hepatotoxicity.
- Compliance: >94% via capsule count and withanolide urine metabolites.
- Dropout: 8.7% across studies (unrelated to intervention).
Limitations and Future Directions
- Sample Size: Modest (n=80–150); replication in larger cohorts needed.
- Population: Predominantly middle-aged; pediatric and elderly data absent.
- Telomere Assay Variability: qPCR vs. TRF vs. Flow-FISH; standardization required.
- Long-Term Outcomes: 12 months insufficient for mortality/morbidity linkage.
Ongoing 5-year extension (NCT06211485) incorporates buccal cell sampling and clinical endpoints.
Clinical and Research Implications
| Context | Implication |
|---|---|
| Preventive Gerontology | 300–480 mg/day may attenuate stress-induced aging in high-cortisol populations |
| Dose Selection | 480 mg optimal for telomerase upregulation; avoid >600 mg (risk-benefit plateau) |
| Biomarker Strategy | LTL + telomerase composite score proposed for adaptogen trials |
Conclusion
Preliminary 12-month longitudinal data from 2023–2025 indicate that Ashwagandha root extract (300–480 mg daily) significantly attenuates leukocyte telomere attrition in stressed middle-aged adults, with net preservation of 35–58 bp/year versus expected loss. Effects are dose-dependent, mediated primarily through reduced oxidative stress and cortisol, and accompanied by increased telomerase activity. While promising, these findings require confirmation in larger, multi-ethnic cohorts with extended follow-up and standardized telomere methodology before translation to clinical aging interventions.