reviewed april 2026|next review october 2026|88 physicians psi has verified|43 published studies
TA-65 (Cycloastragenol)
TA-65 (cycloastragenol) is a single molecule purified from astragalus membranaceus root that activates telomerase through hTERT gene expression upregulation, marketed as a longevity supplement despite limited clinical evidence and an unresolved cancer safety question.
Evidence landscape: 43 published studies
Published studies span telomere biology, immunology, and metabolic markers. Limited human data with one primary clinical study.
- 1 Human
- 41 Animal
- 1 Reviews
Not FDA-approved as a drug. Marketed as a dietary supplement. Claims are not FDA-evaluated. TA-65 is not a peptide in the classical sense but is included in PSI's library for its relevance to telomere biology and the longevity community.
Commercially available as a dietary supplement (TA Sciences). One of the most marketed telomerase activator products. Premium pricing relative to other supplements.
Cycloastragenol is a triterpenoid saponin, not a peptide. It activates telomerase through MAPK-mediated hTERT gene expression upregulation. Included in PSI's compound library because of its prominence in the longevity community that overlaps with peptide research.
PSI Assessment
Telomeres shorten with each cell division, and shorter telomeres are associated with cellular aging. TA-65, a purified compound from astragalus root, activates telomerase, the enzyme that rebuilds these protective chromosome caps. One published human study showed telomerase activation and immune cell biomarker improvements. Mouse studies showed telomere elongation. The critical question remains: does activating telomerase actually slow aging in a meaningful way? And the safety concern is not trivial: telomerase activation is also a hallmark of cancer cells. TA-65 is not a peptide, but its prominence in the longevity community warrants inclusion.
Telomerase activation documented. One human study with immune cell improvements. Mouse telomere elongation. Whether this translates to anti-aging benefit is unproven. Cancer safety concern unresolved.
The mechanism involves upregulation of the hTERT gene, the rate-limiting component of telomerase. TA-65 (cycloastragenol) acts through the MAPK signaling pathway to increase hTERT expression, which increases telomerase activity. In the published human study, this translated to improvements in immune cell telomere length and biomarker changes. The compound also reduced the percentage of critically short telomeres in immune cells in mouse models.
What the evidence supports
TA-65 (cycloastragenol) activates telomerase through hTERT gene expression upregulation. One published human study showed telomerase activation and improvements in immune cell biomarkers. Mouse studies demonstrated telomere elongation. The mechanistic pathway (MAPK-mediated hTERT induction) is documented.
What is not yet established
Whether telomerase activation produces measurable anti-aging or health outcomes in humans. Long-term safety regarding cancer risk, since telomerase activation is also a hallmark of cancer cells. Independent replication of the clinical findings. Whether supplement-level telomerase activation produces biologically meaningful telomere maintenance.
Research Evidence
The findings below cover the telomerase activation evidence, the human study data, and the theoretical safety considerations.
Evidence by condition
Evidence dimensions across telomere biology, immune function, and metabolic markers. The telomerase activation mechanism has the strongest evidence. Clinical outcome data is limited.
| Condition | Mechanism | Animal evidence | Human evidence | Replication |
|---|---|---|---|---|
| Telomere Biology | ||||
| Anti-Aging | ||||
| Immune Aging |
One published human study demonstrated that TA-65 supplementation activated telomerase and produced improvements in immune cell biomarkers including CMV-specific T cell expansion and reduced percentage of senescent T cells.
This is the primary human evidence. The study was conducted with financial support from TA Sciences (the manufacturer). Independent replication has not been published.
In mouse models, TA-65 treatment increased telomere length and reduced the percentage of critically short telomeres, particularly in immune cells. Treated mice showed improvements in glucose tolerance and metabolic markers.
The mouse data is supportive but the gap between mouse telomere biology and human telomere biology is substantial. Mice have much longer telomeres and different telomerase regulation than humans.
A clinical study showed improved metabolic markers (glucose, insulin, cholesterol) in TA-65 users, though the study design limitations make causal attribution uncertain.
The metabolic improvements were observed but the study design (open-label, no placebo control in some analyses) limits the strength of the evidence.
1 Human|41 Animal|1 Reviews
View all 43 indexed studiesHow TA-65 (Cycloastragenol) Works
TA-65 (cycloastragenol) is a triterpenoid saponin purified from Astragalus membranaceus root. It activates telomerase through MAPK-mediated upregulation of hTERT gene expression, the rate-limiting component of the telomerase enzyme.
TA-65 activates telomerase, the enzyme that rebuilds the protective caps (telomeres) on chromosomes. These caps shorten with each cell division and their length is associated with cellular aging. By turning on telomerase, TA-65 may slow or partially reverse this aspect of cellular aging in immune cells.
For a more detailed view of the biology, here is what researchers have observed at the molecular level.
Cycloastragenol derivative activating hTERT. Derived from Astragalus membranaceus.
What is TA-65 (Cycloastragenol) being studied for?
Researchers are studying TA-65 (Cycloastragenol) across several health conditions. Each condition below is labeled with the strength of evidence that exists for that specific use, not for TA-65 (Cycloastragenol) overall. This means a compound can have human studies for one condition but only animal data for another.
Telomere Biology
·PreclinicalTelomerase activation through hTERT upregulation is documented in cell culture and supported by one human study showing immune cell telomere improvements.
Limitations: Whether supplement-level telomerase activation produces biologically meaningful telomere maintenance in humans is not established. The human study has not been independently replicated.
Anti-Aging
·PreclinicalImmune cell biomarker improvements and metabolic marker changes observed in the published human study. Whether these translate to meaningful lifespan or healthspan extension is unknown.
Limitations: No long-term outcome data. No evidence that TA-65 extends lifespan or healthspan in humans. The anti-aging claim rests on telomere biology extrapolation rather than clinical outcome evidence.
Immune Aging
·PreclinicalOne human study showed reduced senescent T cell percentage and improved CMV-specific T cell expansion. Mouse data supports immune cell telomere improvements.
Limitations: Single study without independent replication. The clinical significance of these immune biomarker changes for infection resistance or immune function is not established.
Safety and Regulatory Status
FDA Status: Not FDA-approved as a drug. Marketed as a dietary supplement. Supplement claims are not FDA-evaluated. TA-65 is a small molecule, not a peptide.
Availability: Commercially available as a dietary supplement from TA Sciences. Premium-priced longevity supplement. Available without prescription.
Class context: The theoretical cancer safety concern is the most important consideration. Telomerase activation is also a hallmark of cancer cells. Published studies have not observed increased cancer incidence, but long-term studies with adequate statistical power to detect this risk have not been conducted.
Published studies report no significant adverse effects. The theoretical cancer concern (telomerase activation is a hallmark of cancer) has not been resolved by long-term safety data. The risk-benefit assessment depends on whether telomerase activation at supplement doses meaningfully affects cancer risk.
Questions and Comparisons
Questions the evidence raises for a TA-65 (Cycloastragenol) discussion.
Frequently Asked Questions
References
Each citation links to the original study on PubMed, the U.S. National Library of Medicine database.
- 1.One-year observational study of 114 subjects taking the telomerase activator TA-65 (cycloastragenol derived from Astragalus membranaceus). The study found a significant increase in the percentage of short telomeres rescued by telomerase activation, along with improvements in several immune markers including reduced senescent cytotoxic T cells.Harley CB et al., 2011 in Rejuvenation Res. View on PubMed
- 2.Randomized, double-blind, placebo-controlled trial of TA-65 in 117 relatively healthy CMV-positive subjects aged 53 to 87. After 12 months, low-dose TA-65 (250 units) significantly lengthened critically short telomeres compared to placebo, with the effect most pronounced in subjects with the shortest baseline telomere lengths.Salvador L et al., 2016 in Curr Pharm Des. View on PubMed
- 3.Preclinical study showing that TA-65 supplementation in aging mice increased telomerase activity, reduced the percentage of critically short telomeres, and improved markers of health span including glucose tolerance and osteoporosis measures. Importantly, no increase in cancer incidence was observed despite the telomerase activation.de Jesus BB et al., 2011 in Aging Cell. View on PubMed
- 4.Clinical study evaluating TA-65 supplementation in 40 middle-aged adults over 6 months. The treatment group showed trends toward telomere lengthening and improvements in select cardiometabolic markers. The study added to the evidence that telomerase activation through nutraceutical supplementation may have measurable biological effects.Fernandez ML et al., 2019 in Complement Ther Clin Pract. View on PubMed
Medical Disclaimer
This content is for educational and informational purposes only and does not constitute medical advice. The information presented reflects published research as indexed by PSI and should not be used to make treatment decisions. Always consult a qualified healthcare provider before starting, stopping, or modifying any treatment.