Cycloastragenol

PhytochemicalTriterpene saponinBest in the morning

What is it

Cycloastragenol is a triterpenoid sapogenin (aglycone of astragalosides) derived from the root of Astragalus membranaceus, a herb central to traditional Chinese medicine. It is best known as the active fragment marketed in 'TA-65' and other 'telomerase activator' supplements for anti-aging.

Evidence for 3 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Immune cell senescence

Limited Evidence

Small trials of TA-65 report modest changes in immune cell subset composition, including reductions in senescent T-cells, in older adults. Clinical relevance is unclear.

Telomere length

Limited Evidence

Small trials report modest increases in average leukocyte telomere length, particularly of the shortest telomeres. Whether this affects health outcomes is unknown.

Anti-aging or longevity

Mixed Evidence

No evidence supports meaningful effects on aging-related clinical outcomes such as lifespan or disease incidence.

How it works

In cell culture, cycloastragenol modestly activates telomerase, the enzyme that maintains the protective DNA caps on chromosomes (telomeres). Telomere shortening is associated with cellular aging, and the hypothesis behind cycloastragenol products is that activating telomerase could slow cellular aging or restore certain immune cell functions. Most human evidence comes from one product (TA-65). Some trials report modest improvements in immune cell composition (particularly senescent T-cells) and small increases in average telomere length in select populations. Whether this translates to meaningful clinical benefit, and what the long-term effects of chronic telomerase activation are (including theoretical cancer risk), remain unresolved.

Dosage

No established RDA. Most TA-65 trials use 5-25 mg/day of standardized cycloastragenol. There is no defined upper limit, but long-term safety is not well characterized.

When and how to take it

Most products are taken once daily, usually in the morning, with or without food. Effects (if any) develop over months of continuous use.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Standardized cycloastragenol (TA-65)

Branded ingredient with most of the published clinical data.

Lipophilic; bioavailability is limited orally and varies across formulations.

Whole-root Astragalus extract

Traditional form; cycloastragenol content is lower than in concentrated products.

Contains cycloastragenol along with astragalosides and polysaccharides.

Safety

Short-term trials report no major adverse effects at typical doses. Long-term safety is the central unknown: the theoretical concern is that telomerase activation could promote tumor growth in pre-existing cancers or precancerous cells, though this has not been demonstrated in clinical trials.

Who should be cautious

Avoid in pregnancy and breastfeeding due to lack of data. People with active or recent cancer, precancerous conditions, or strong family history of cancer should be cautious because of telomerase-related theoretical concerns. People on immunomodulatory medications should consult a clinician.

Interactions

No specific interactions reliably reported. Theoretical concerns about combining with hormone therapies or in active malignancy.

Frequently asked questions

Does cycloastragenol slow aging?⌄

No human trial has shown effects on clinical aging outcomes like lifespan or disease incidence. Reported effects on telomeres and immune cells are biomarker changes whose clinical importance is unproven.

Is it safe long term?⌄

Short-term trials show no major adverse effects, but long-term safety, including any potential cancer-related concerns, is not well characterized.

References

Cycloastragenol on Wikidata — Wikidata link

Cycloastragenol on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Cycloastragenol (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.