Telomerase gene therapy
What is telomerase gene therapy?
Telomerase gene therapy uses a virus to deliver the gene for telomerase, an enzyme that rebuilds telomeres, the protective caps on chromosome ends that shorten as cells divide. Lengthening them extended life in mice. In people it has only been tried outside approved trials, most famously by BioViva founder Liz Parrish in 2015. Its safety is unknown.
Listed here because well-known people have tried it on themselves. Trying something is not recommending it; each entry says whether the person tells others to do it.
Who has tried it
Tried by 1 person we can source: 1 testing.
Testing
Liz ParrishFounder and CEO of BioViva
Started Sep 2015 · Does not recommend it to others
Had an unapproved telomerase gene therapy abroad in 2015, hoping to lengthen her telomeres, and has continued experimenting on herself since.
“the most genetically modified person on Earth.”
MIT Technology Review, Why reprogramming is the buzziest approach to reversing aging right now (June 2026) · Status checked June 12, 2026 · Suggest a correction
What the evidence shows
No controlled human study has tested telomerase gene therapy. The only human reports come from self-experiments outside trials, chiefly Liz Parrish's in 2015. Indirect evidence comes from a different approach: in people with inherited telomere diseases, the hormone danazol, which raises telomerase activity, lengthened telomeres in almost everyone assessed after two years [1].
In mice, a single dose of a virus carrying the telomerase gene, given at one or two years of age, improved several aging measures and raised median lifespan by 24% and 13% without more cancer [2]. Mice built from cells with extra-long telomeres were leaner, had less cancer and lived longer [3]. A 2022 study reporting longer life from a telomerase gene carried by a different virus was retracted in 2025 [4].
The main worry in people is cancer. Genes that predict longer telomeres are linked to higher risk of several cancers and lower risk of heart disease [5]. Shorter telomeres are linked to higher death rates in large cohorts [6], but that does not show that lengthening them helps. No telomerase gene therapy is approved by the FDA [7].
Safety
- No telomerase gene therapy is approved by the FDA or any major regulator. People who have had it got it abroad, outside approved trials.
- Most cancers rely on telomerase to keep dividing, and genetic studies link longer telomeres to higher risk of several cancers [@haycock2017].
- A gene therapy may be hard or impossible to reverse once the gene is in cells, and the virus used to deliver it can trigger immune reactions.
- Long-term effects in healthy people are unknown.
Common questions
Did Liz Parrish get telomerase gene therapy?
Yes. In September 2015 she received an unapproved telomerase gene therapy by vein, along with follistatin gene injections into muscle, reportedly in Colombia. In 2016 BioViva reported that her white blood cell telomeres had grown longer, a result from one person rather than a controlled study.
Does telomerase gene therapy reverse aging in humans?
Unknown. It improved health and lifespan in mice [2], but it has never been tested in a controlled human trial.
Does lengthening telomeres cause cancer?
Is telomerase gene therapy FDA approved?
No. No telomerase product is on the FDA's list of approved cell and gene therapies [7].
Sources
- 1.Townsley DM, Dumitriu B, Liu D, et al. Danazol Treatment for Telomere Diseases. N Engl J Med, 2016. doi:10.1056/NEJMoa1515319
- 2.Bernardes de Jesus B, Vera E, Schneeberger K, et al. Telomerase gene therapy in adult and old mice delays aging and increases longevity without increasing cancer. EMBO Mol Med, 2012. doi:10.1002/emmm.201200245
- 3.Muñoz-Lorente MA, Cano-Martin AC, Blasco MA. Mice with hyper-long telomeres show less metabolic aging and longer lifespans. Nat Commun, 2019. doi:10.1038/s41467-019-12664-x
- 4.Jaijyan DK, Selariu A, Cruz-Cosme R, et al. New intranasal and injectable gene therapy for healthy life extension. Proc Natl Acad Sci U S A, 2022. doi:10.1073/pnas.2121499119
- 5.Telomeres Mendelian Randomization Collaboration, Haycock PC, Burgess S, et al. Association Between Telomere Length and Risk of Cancer and Non-Neoplastic Diseases: A Mendelian Randomization Study. JAMA Oncol, 2017. doi:10.1001/jamaoncol.2016.5945
- 6.Wang Q, Zhan Y, Pedersen NL, et al. Telomere Length and All-Cause Mortality: A Meta-analysis. Ageing Res Rev, 2018. doi:10.1016/j.arr.2018.09.002
- 7.U.S. Food and Drug Administration. Approved Cellular and Gene Therapy Products. U.S. Food and Drug Administration, 2026. Link