TA-65
TA-65 is a supplement purified from the Astragalus plant and sold as a telomerase activator, a way to switch back on the enzyme that rebuilds the protective caps on your chromosomes. One small trial, funded and partly written by the company that sells it, reported longer telomeres on the low dose; the higher dose showed no significant change, no trial has shown a benefit to health outcomes, and the cancer question is unanswered.
Don't take TA-65 for aging. The evidence is thin and mostly industry-funded, and switching telomerase on is exactly what most cancers do.
What it is meant to do
Telomeres are stretches of repetitive DNA at the ends of each chromosome that shorten a little every time a cell divides; telomerase is the enzyme that adds the repeats back. It is switched off in almost all adult body cells. TA-65 is marketed as a way to turn it back on, on the theory that longer telomeres mean younger cells. The biology, and why longer is not simply better, is on Telomere attrition.
Why that is a worry
Roughly 80 to 85% of human cancers switch telomerase back on, because limitless division is exactly what a tumour needs.[1] The shutdown of telomerase in adult tissue is in part a tumour-suppression system, so switching telomerase back on risks loosening one of the body's built-in brakes on cancer.
The human trial
In a year-long placebo-controlled trial in 117 adults aged 53 to 87 who carried cytomegalovirus, a common chronic virus, the 23 people on the low dose gained about 530 base pairs of average telomere length while the placebo group lost about 290. The four-times-higher dose showed no significant change, and 20 participants did not finish.[2]
Every author was funded by, employed by or consulting for TA Sciences, the company that sells the supplement, and Life Length, a company that sells telomere-length measurement, did the measurements.[3] Telomere length was the outcome, not any measure of health, and the tests used to track telomeres are noisy; see Telomere length test.
A later randomised trial, also maker-funded, in 90 heart-attack survivors over 65 missed its main immune-aging goal and did not measure telomeres.[4]
The cancer-safety evidence
The only safety study aimed at cancer was in animals. A small study in hairless mice exposed to ultraviolet light, paid for by the manufacturer, found no overall difference in when skin tumours appeared, how many mice got them or total tumour load. But the mice given it before, during and after exposure had more tumours of 2 mm or larger at two time points (one of them only borderline), and with ten mice per group the study cannot rule out harm.[5]
The long-term cancer question in humans is unresolved.
What to do
- Don't take TA-65, or other "telomerase activators", for aging.
- Don't use a telomere test to judge whether a supplement is working; the year-to-year change in one person is mostly measurement noise.
- If you want to protect your telomeres, do what protects everything else: not smoking, a healthy weight, regular aerobic exercise, good sleep. None is proven to change telomeres themselves, but they are worth doing for other reasons.
Further reading
- Salvador L, et al. A natural product telomerase activator lengthens telomeres in humans: a randomized, double blind, and placebo controlled study. Rejuvenation Res 2016.[6]
- Bawamia B, et al. Activation of telomerase by TA-65 enhances immunity and reduces inflammation post myocardial infarction. Geroscience 2023.[7]
- Burke KE, et al. The safety of oral telomerase activator in UV-induced skin cancer, with a review of telomerase in aging and skin carcinogenesis. OBM Geriatrics 2021.[8]
- Iskandar M, et al. A review of telomere attrition in cancer and aging: current molecular insights and future therapeutic approaches. Cancers (Basel) 2025.[9]