Astragalus, Ashwagandha, Longevity and Our Telomeres: Anti-Aging Benefits
by Nils Osmar | March 2026
The information in this article is not intended as, and should not be taken as, medical advice. Interventions like exercising, dietary changes, and taking medications and supplements can have both benefits and side effects, Please consult with a medical professional about any medical concerns. See full Medical Disclaimer
Quck Summary:
Every cell division shortens our telomeres — the protective caps on our chromosomes — and as they shorten, cellular aging accelerates. In this article, I explore two adaptogenic herbs with evidence for supporting telomere health: astragalus (specifically its active compounds astragaloside IV and cycloastragenol) and ashwagandha.
Astragalus has the stronger and more direct clinical evidence, including a rigorous 2024 randomized trial showing measurable telomere lengthening and a 2025 meta-analysis confirming moderate but significant effects.
Ashwagandha’s telomere-specific evidence is largely from cell studies, but it may support telomere health indirectly by reducing the chronic stress, inflammation, and oxidative damage that speed up cellular aging. The article also addresses the cancer question honestly — theoretical concern exists, but no increased risk has been found in trials to date — and notes that telomere lengthening is a promising but still-maturing field. Additional lifestyle factors (omega-3s, vitamin D3, exercise, stress reduction, and dietary interventions) also play a documented role.
In several points in the article, I mention a supplement called TA-65. It appears repeatedly because it has been the most studied natural telomerase activator in clinical trials, so appears in several trial studies. I should clarify though that no independent comparative studies have established that it is superior to other high-quality standardized cycloastragenol supplements at equivalent doses. Much of the research on TA-65 has been industry-funded, which should be weighed when evaluating its marketing claims. I don’t take it or endorse it myself.
I was walking with a friend and mentioned that I take a supplement called astragalus — partly to protect my telomeres, the protective end caps on the strands of our DNA. I also alternate it with ashwagandha, another adaptogenic herb with overlapping but distinct anti-aging properties. My friend’s reaction: “Why does it matter if those get shorter? Our DNA did its work when we were created.”
It’s a fair question. The answer has to do with a process most of us don’t think much about: the ongoing, lifelong rebuilding of our bodies, cell by cell.
What Are Telomeres, and Why Do They Matter?
Telomeres are protective structures at the ends of our chromosomes — sequences of repetitive DNA (TTAGGG, repeated thousands of times) that act as buffers during cell division. A common analogy compares them to the plastic tips on the ends of shoelaces: without them, the lace unravels. Elizabeth Blackburn, one of the Nobel laureates who discovered the role of telomeres in aging, used exactly this comparison.
A more functional image: think of the telomere as the scaffolding a repair crew stands on when maintaining a long structure. Each time the structure is repaired (each cell division), the scaffold gets slightly shorter. Eventually the crew can’t reach the damaged sections anymore, and things start falling apart.
Our bodies aren’t built once and left alone. They’re continuously rebuilt. Some cell types turn over every day; others every few months; others over years or decades. Every time a cell divides to replace an old one, it uses the chromosomal blueprint — and every time it does, the telomeres get a little shorter. This is called the “end replication problem,” a structural limitation of how DNA polymerase copies chromosomes.
The Trouble with Telomere Shortening
As telomeres shorten over time, several problems compound:
• Increasing genetic errors accumulate during cell replication, because the blueprint becomes harder to read accurately.
• Cells eventually reach a state called replicative senescence — they stop dividing altogether when telomeres hit a critically short length.
• Senescent cells don’t just sit quietly. They actively secrete pro-inflammatory compounds and damaging enzymes into surrounding tissues, contributing to what researchers call “inflamm-aging.”
• Short telomere length has been associated in population studies with elevated risk of cardiovascular disease, cognitive decline, and several cancers.
The Nobel Prize in Physiology or Medicine in 2009 was awarded to Elizabeth Blackburn, Carol Greider, and Jack Szostak for their discovery of how chromosomes are protected by telomeres and the enzyme telomerase. Their work established the foundational science behind everything that follows in this article.
Telomerase: The Repair Enzyme
Telomerase is a specialized enzyme — technically a reverse transcriptase — that rebuilds telomere length by adding new repetitive sequences to chromosome ends. In young, actively dividing cells like stem cells and immune cells, telomerase is active. In most mature adult somatic cells, it’s largely switched off, which is why our telomeres shorten over time.
Researchers have been searching for safe ways to reactivate or boost telomerase activity in normal cells — ideally to the level that maintains telomere length without triggering uncontrolled cell growth. This is the central challenge, and the central promise, of telomere-targeted anti-aging research.
Astragalus: The Stronger Evidence
Astragalus membranaceus (known as Huang Qi in traditional Chinese medicine) has been used medicinally for over two thousand years. Modern research has focused on two of its active compounds: astragaloside IV and cycloastragenol (CAG). Both are classified as triterpenoid saponins, and both have been identified as potent activators of telomerase.
Cycloastragenol is also the active ingredient in a commercial supplement called TA-65, which has been the most clinically studied natural telomerase activator to date.
What the Recent Research Shows
A 2024 randomized, double-blind, placebo-controlled trial published in the journal Nutrients (de Jaeger et al.) tested an astragalus-based supplement complex on 40 healthy middle-aged adults (average age 56) over six months. Participants taking the supplement showed statistically significant increases in both median and short telomere lengths, while the placebo group showed no change. No adverse side effects were reported. This is among the most rigorous human trials published to date specifically on telomere length.
A 2025 meta-analysis in PMC evaluated eight randomized controlled trials (750 participants total, mean age 63) on TA-65 supplementation and found moderate but statistically significant telomere elongation across trials (SMD = 0.47), with stronger effects in adults over 60. Secondary benefits included reductions in inflammatory markers and improvements in immune function markers.
A September 2025 review published in the Journal of Cardiovascular Development and Disease highlighted astragalus-derived compounds as showing “significant promise” in attenuating vascular aging, through both telomere-related and independent mechanisms including antioxidant, anti-inflammatory, and endothelial-protective effects.
It’s worth noting: a summary on Examine.com of the same 2024 de Jaeger trial rated the telomere lengthening finding as not statistically significant by their analysis criteria — a reminder that how studies are evaluated matters, and the field is still developing. The sample sizes in these trials are small. Long-term human data is limited. More replication is needed.
That said, the weight of evidence for astragalus/cycloastragenol is more robust than for almost any other natural telomerase activator, and it continues to grow.
Ashwagandha is Promising but Different
Ashwagandha (Withania somnifera), a cornerstone herb in Ayurvedic medicine and sometimes called Indian ginseng, has a different and somewhat more indirect relationship with telomere biology. Its telomerase-related evidence base is largely in vitro (cell culture), not yet in robust human clinical trials.
The key study (Raguraman & Subramaniam, 2016) found that KSM-66 ashwagandha root extract increased telomerase activity in human HeLa cells by approximately 45% at effective concentrations. This is meaningful data, but HeLa cells are a cancer cell line — results in cancer cells don’t automatically translate to effects in normal, healthy somatic cells.
A comprehensive 2025 review in Biogerontology (Springer Nature) documented ashwagandha’s broader anti-aging effects, including its telomerase-enhancing properties, while acknowledging that the telomere-specific evidence comes from in vitro work rather than clinical trials. The herb’s more well-documented anti-aging mechanisms include:
• Significantly reducing cortisol levels (up to 27.9% in clinical trials), which matters because chronic elevated cortisol accelerates cellular aging and telomere attrition.
• Reducing systemic inflammation (NF-κB suppression, lower CRP and IL-6 levels).
• Mitigating mitochondrial dysfunction via the Nrf2 antioxidant pathway.
• Improving sleep quality and stress resilience.
The bottom line on ashwagandha: its telomere-specific claims are less directly established than astragalus’s, but it may support telomere health through multiple indirect pathways — particularly by reducing the oxidative stress and chronic inflammation that accelerate telomere shortening in the first place. It’s doing a different job, and arguably an important one.
The Cancer Question: What We Know, and Where Questions Remain
This deserves more than a parenthetical. Telomerase is a double-edged molecule. Cancer cells famously hijack it — telomerase is active in over 90% of human cancers, helping tumors achieve the cellular immortality that makes them dangerous. So the reasonable concern is: could boosting telomerase in healthy people inadvertently help dormant cancer cells proliferate?
Here’s what the research currently suggests:
• No clinical evidence of increased cancer risk has been found in trials using TA-65/cycloastragenol to date, including a five-year follow-up study. A mouse study found similar overall cancer incidence between TA-65-treated and control animals.
• The degree of telomerase activation from natural supplements like cycloastragenol appears modest — far below the levels seen in cancer cells, and likely below the threshold for promoting tumor growth in people without existing cancer.
• The studies conducted so far are relatively short-term. Cancer takes years or decades to develop, so one-year and even five-year studies may not be long enough to detect any risk that exists.
• People with active cancer, or known cancer risk factors, should be especially cautious and should discuss telomerase-activating supplements with their oncologist before taking them.
The honest assessment: the cancer concern is theoretically real and worth taking seriously. The available evidence is reassuring but not definitive. This is an area where long-term data — which we don’t yet have — will be decisive.
Does Telomere Lengthening Actually Extend Lifespan?
The honest answer is: we don’t fully know yet.
Telomere length is a marker of cellular aging, not a simple dial we can turn up to live longer. The relationship is nuanced. Mice, for example, have significantly longer telomeres than humans — but obviously shorter lives. And humans with genetically longer telomeres have lower rates of some diseases but higher rates of others, including certain cancers.
What gene therapy experiments in mice have shown: when telomerase expression was increased in middle-aged mice, they lived 13–24% longer on average and showed improved metabolic markers, bone density, and muscle function — without increased cancer incidence in those studies. This is more direct evidence than supplement studies and more encouraging than the earlier “not in mammals” claim your original article made.
For natural supplement-level telomerase activation in humans, the evidence for healthspan benefits (healthier, better-functioning cells) is building. Evidence for actual lifespan extension in humans remains unproven. The two are related but not identical goals.
Other Things That Support Telomere Length
Supplements aren’t the only tools here. The following have research support for slowing telomere attrition or supporting telomere maintenance:
• Omega-3 fatty acids: A dose-response relationship between blood omega-3 levels and telomere length has been documented. The relevant variable appears to be actual circulating levels, not just dose taken.
• Vitamin D3: A major randomized controlled trial (VITAL) found that vitamin D3 supplementation significantly slowed telomere shortening over four years, preventing the equivalent of nearly three years of aging-related shortening compared to placebo.
• Regular aerobic exercise: Consistently associated with longer telomeres in population studies.
• Stress reduction: Chronic psychological stress measurably accelerates telomere shortening. Practices that reduce cortisol — including meditation, adequate sleep, and social connection — are relevant.
• Mediterranean dietary patterns:Multiple studies have associated adherence to a Mediterranean-style diet with longer telomere length. (Note: The MD has not been proven to be the only diet associated with improved telomeres; many alternative diets have not yet been tested.)
ITP Studies?
Neither astragalus nor ashwagandha has been independently tested by the NIA’s Interventions Testing Program (the gold standard for lifespan research in mammals). Ashwagandha was included as one component of a combination supplement called PB125, which failed to show significant lifespan extension in that context.
Fasting and Telomerase — and Some Speculation
This section is a bit speculative, but I think the reasoning is sound enough to share.
When you fast for three to five days (or follow a fasting-mimicking protocol), the body enters a survival state in which it actively seeks out damaged and dysfunctional cells to cannibalize for fuel. One of the signals it uses to identify these cells is critically short or damaged telomeres. Senescent cells — old, non-dividing cells leaking inflammatory compounds — are preferentially targeted during this autophagic clearing process.
If you take telomerase boosters during a prolonged fast, you may be obscuring the very signals your body uses to identify which cells to clear. You’re patching over the damage markers before the cleanup crew can read them.
My personal practice: I pause astragalus and ashwagandha during any fast longer than 24 hours, then resume when I’m eating normally again. This is not established medical guidance — it’s a precautionary approach based on the logic of the biology.
This also speculation on my part, but I suspect that supporting our telomere health by taking supplements such as astragalus, as a part of a protocol related to what is called vesicle-driven rejuvenation, could in theory result in a longer lifespan in humans as it has in mice. See article: Vesicle-Driven Rejuvenation and “Rivers”: New Evidence of Dramatic Life Extension and Rejuvenation in Mice.
What I Currently Take and Why
I take both astragalus and ashwagandha from Gaia Herbs, a company I’ve had consistently good experiences with in terms of quality and sourcing. I alternate between them rather than taking both simultaneously — not because there’s strong evidence against combining them, but out of general caution about always cycling supplements.
For anyone considering these supplements: astragalus/cycloastragenol has the stronger and more direct evidence specifically for telomere lengthening. Ashwagandha’s anti-aging case is real but rests more on its ability to reduce the conditions (chronic stress, inflammation, oxidative damage) that accelerate aging generally.
Both are adaptogenic herbs with long safety records and multiple documented benefits beyond telomere biology. Neither has shown serious adverse effects in the research literature at typical supplemental doses.
A Note on Uncertainty
Telomere science is moving fast but is still maturing. In 2024 alone, researchers unveiled Telo-seq, a new high-resolution sequencing method that can measure individual telomere lengths and distinguish telomerase-maintained from ALT-maintained telomeres for the first time — opening up entirely new research possibilities. What we know in 2026 will likely look incomplete by 2035.
Please consult a healthcare professional before making significant changes to your supplement regimen, especially if you have existing health conditions.
About the author: https://newlifelongevity.com/about-the-author/
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More from Nils Osmar
- Anti-Aging Youtube channel Pathways to Longevity
- Anti-Aging Facebook group: Anti-Aging and Life Extension
- Rekindle School classes in Seattle: Rekindl.e School
- My personal website: My articles, art and more: Nilsosmar.com
- Exploring possible consciousness in Claude.AI and other LLMs: AI Consciousness
