TA-65 is an isolate of a proprietary extract of the dried root of Astragalus membranaceus, which is found to be connected with an "age-reversal" effect in the immune system, in that it leads to declines in the percentage of senescent cytotoxic T cells and natural killer cells after six to twelve months of use. There is, however, no relevant data available with regard to the characterisation of this isolate, and the type of constituents responsible for the purported effects.

Telomerase activation might pose an increased risk of cancer because telomere

Telomere

A telomere is a region of repetitive DNA sequences at the end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Its name is derived from the Greek nouns telos "end" and merοs "part"...

shortening is a mechanism that limits cell proliferation. However, short telomeres result in chromosome instability, hence there is also a potential mechanism for telomere lengthening to protect against cancer. To date, studies of drug-induced activation of telomerase (as distinct from mutation-induced activation ) have shown no evidence of a cancer-promoting effect.

The proprietary production process starts with 3 tons of plant material per batch and ends up with capsules containing 5mg of TA-65. In October of 2010 Intertek/AAC Labs, an ISO 17025 internationally recognized lab, found the largest component of TA-65 to be Cycloastragenol which has been proven to activate telomerase in CD8+ T lymphocytes in human immune cells.