Recently I became aware of Sierra Sciences, a startup founded by William Andrews, previously of Geron. Andrews had done a lot of research on telomeres and telomerase.
Your cells have nuclei in them where your DNA is wadded up into packets called chromosomes. On the ends of the DNA strands there's a thing called a telomere. It protects the DNA from unravelling, like the little plastic tube on the end of your shoelace. Our telomeres shorten as we get older, and longer telomeres are strongly correlated with youth and vigor and health. There are many contributors to ageing but telomere length is currently regarded as one of the most urgent and one of the best understood.
Our reproductive cells do not suffer this effect. If we passed on shorter telomeres to our kids, they wouldn't live long, and they probably couldn't have kids of their own. To accomplish this, our reproductive cells produce stuff called telomerase which protects the telomeres from shortening. Here's the cool part: the gene for producing telomerase is present in ALL our cells, but it's only switched on in the reproductive cells. So there's a research push to find a telomerase activator that switches on the gene in all our cells. Sierra Sciences is one of the companies involved in this research.
You can buy a telomerase activator today, called TA-65. It's expensive, about $1500 per month, I think. But I haven't yet found any compelling evidence that it's a scam or a significant health risk. So I'm toying with the idea of trying it for a few months and see if I feel any different.
There is also a clinical test to measure the length of your telomeres. I know it exists but I don't know much more about it at the moment.