'Soon, telomeres were hailed as a secret to aging — companies advertised that they could tell your biological age by measuring the length of your telomeres. Others said that you could extend your life by preserving your telomeres with supplements.

But Dr. Armanios and other researchers had noticed that telomere lengths seemed constrained to a narrow range, indicating there is a price to pay for very long or very short telomeres.'

https://www.nytimes.com/2023/05/04/health/long-telomeres-age-longevity.html