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Cya3.8
Cycloastragenol (TA-65) Research
Mostly mechanism / observationalLimited safety
7 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Cycloastragenol (TA-65) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 2008–2025 with a typical study size of 117 participants.
Based on 7 studies · 1 RCT · 117 total participants
Confidence
Low
By outcome
Longevity & telomeresGenuinely activates telomerase and lengthened telomeres in one small RCT, but no human study shows extended lifespan or healthspan; telomere length is a surrogate marker · Ongoing
Mostly mechanism / observational7 studies
Immune & T-cell agingRemodeled the immune profile toward a younger pattern (fewer senescent T cells) in an open-label pilot, mostly in CMV-positive subjects; not confirmed in a controlled immune-endpoint trial · 3-6 months
Mechanistic / preclinical and clinical literature1
Experimental and clinical literature1
Adult/old mice1
Steady research
1 study in the last 5 years
200820162025
1Telomere length change over 12 monthsRCTn=117 · medium study2016
Subjects taking the low dose of TA-65 (250 U) significantly increased TL over the 12 months period (530 ± 180 bp; p = 0.005), whereas subjects in the placebo group significantly lost TL (290 ± 100 bp; p = 0.01).
Salvador L, Singaravelu G, Harley CB, Flom P, Suram A, Raffaele JM · Rejuvenation Research (2016)
Randomized, double-blind, placebo-controlled trial of TA-65 over 12 months in 117 relatively healthy CMV-positive adults aged 53-87.
The low dose (250 U) significantly lengthened telomeres; the placebo group lost telomere length.
The high dose (1000 U) showed only a non-significant trend — more was not better.
2Telomere-targeting in vascular aging (narrative review)Review2025
This review provides an overview of the mechanistic basis underlying the anti-atherosclerotic effects of Astragalus-derived compounds and underscores critical key knowledge gaps.
Canale P, Andreassi MG · Journal of Cardiovascular Development and Disease (2025)
Recent review of astragaloside IV, cycloastragenol, and TA-65 for vascular aging and atherosclerosis.
Describes plausible anti-inflammatory, antioxidant, endothelial-protective and telomerase-modulating mechanisms.
Explicitly underscores critical knowledge gaps and the need to validate efficacy in clinical trials.
3Anti-aging mechanisms of Astragalus / TA-65 (narrative review)Review2017
A proprietary extract of the dried root of Astragalus membranaceus, called TA-65, was associated with a significant age-reversal effect in the immune system.
Liu P, Zhao H, Luo Y · Aging and Disease (2017)
Review of Astragalus and TA-65 across lifespan extension, vascular aging, brain aging, and cancer effects.
Notes that Astragalus components increase telomerase activity and have reported anticancer, antioxidant and immunoregulatory effects.
Frames TA-65's immune age-reversal as a finding within a still-experimental, mostly preclinical evidence base.
4Short-telomere elongation and health-span markers in miceAnimal2011
TA-65 dietary supplementation in female mice leads to an improvement of certain health-span indicators including glucose tolerance, osteoporosis and skin fitness, without significantly increasing global cancer incidence.
Bernardes de Jesus B, Schneeberger K, Vera E, Tejera A, Harley CB, Blasco MA · Aging Cell (2011)
TA-65 (purified from Astragalus root) elongated critically short telomeres and reduced DNA damage in mouse cells via a telomerase-dependent mechanism.
The effect was absent in telomerase-deficient cells, pinning the action to the telomerase pathway.
Dietary TA-65 improved some health-span markers (glucose tolerance, osteoporosis, skin) in mice.
5Immune-cell remodeling and short-telomere percentageOpen-Label2011
We conclude that the protocol lengthens critically short telomeres and remodels the relative proportions of circulating leukocytes of CMV(+) subjects toward the more "youthful" profile of CMV(-) subjects.
Harley CB, Liu W, Blasco M, Vera E, Andrews WH, Briggs LA, Raffaele JM · Rejuvenation Research (2011)
Likely real
Open-label first-year analysis of the commercial TA-65 'PattonProtocol-1' (TA-65 10-50 mg/day plus a supplement pack), focused on the immune system.
Declines in senescent cytotoxic CD8+/CD28- T cells and natural killer cells, mostly in CMV-positive subjects.
Mean telomere length did not increase, but the percentage of short (<4 kbp) telomeres fell significantly (p = 0.037).
6Telomerase activation and antiviral T-cell functionIn Vitro2008
Exposure of CD8(+) T lymphocytes from HIV-infected human donors to a small molecule telomerase activator (TAT2) modestly retards telomere shortening, increases proliferative potential, and, importantly, enhances cytokine/chemokine production and antiviral activity.
Fauce SR, Jamieson BD, Chin AC, Mitsuyasu RT, Parish ST, Ng HL, Kitchen CM, Yang OO, Harley CB, Effros RB · Journal of Immunology (2008)
Foundational mechanism paper: the cycloastragenol-derived activator TAT2 modestly slowed telomere shortening in human CD8+ T cells ex vivo.
It increased proliferative potential and enhanced antiviral cytokine/chemokine production.
The enhanced antiviral effect was abolished by a specific telomerase inhibitor, confirming the action is through telomerase.
7Telomerase activation in neuronal cellsIn Vitro2014
CAG stimulates telomerase activity in human neonatal keratinocytes and rat neuronal cells, and induces CREB activation followed by tert and bcl2 expression.
Ip FC, Ng YP, An HJ, Dai Y, Pang HH, Hu YQ, Chin AC, Harley CB, Wong YH, Ip NY · Neurosignals (2014)
Cycloastragenol (the aglycone of astragaloside IV) stimulated telomerase activity in human keratinocytes and rat neurons.
It activated CREB and induced telomerase reverse transcriptase (TERT) expression in cortical neurons.
Oral cycloastragenol attenuated depression-like behavior in mice over 7 days.