Most people think of aging as something inevitable. But not all agree and the research into aging and how to reverse it has become more and more prominent over the last couple of years. Most attempts to slow or reverse aging have of course been conducted in rats and mice. They focused, for example, on giving older animals blood or plasma concentrates from younger animals or simply replacing some of the old plasma with albumin.
Anti aging drugs for humans
Now we have some small, but promising evidence in humans. Fahy et al. gave 9 men a cocktail of three drugs over X weeks. These drugs were growth hormone (GH), metformin and dehydroepiandrosterone (DHEA). The former is a naturally occurring hormone that (as you might have guessed from the name) induces growth processes in the human body.
The tissue especially targeted by GH in this intervention is the thymus. In the thymus, T-cells, which are responsible for the cellular response of your immune system, grow and mature. The thymus is therefore an integral part of the body’s adaptive immune system.
After puberty, however, the thymus slowly shrinks and its function is replaced by fat. Growth hormone seems to be able to reverse that process to some extent. In all nine participants, some of the fat tissue was replaced with functioning thymus tissue again.
Metformin is a drug used to treat diabetes that is also a somewhat promising candidate for a drug that increases longevity. Evidence that it increases lifespan in patients with diabetes is very good. There are, however, no good randomized control trials yet for healthy people. The TAME study aims to do exactly this, but it has not yet launched. You can find an extensive review of metformin here.
DHEA is a naturally occurring pro-hormone that gets converted to e.g. testosterone or estrogen in the human body. It is sold in the US as a dietary supplement to increase longevity. I know very little about it, but e.g. the Mayo Clinic advises against taking DHEA.
Effects on study participants
The nine study participants showed signs of rejuvenation in their thymus tissues. All of them showed a change in cellular methylation patterns. These epigenetic patterns, discovered by Steve Horvath, are a very accurate way of estimating the biological age of an organism.
What to make of this
We should not put a lot of hope or trust in a study with only nine participants. What made me a bit more optimistic though, is that effects could be measured in all of the nine participants. This to me doesn’t seem to be the result of ordinary p-hacking. So either something is fundamentally wrong with the study. Or there maybe is grounds for at least a tiny little bit of optimism that the effect is real.
Another problem may be with only looking at methylation patterns. I have to do some more research into this, but maybe an aging pattern that looks younger does not necessarily mean you will live longer? Consider this: The number of wrinkles in the face may normally be considered a very good predictor of age and life expectancy. However, a procedure that removes wrinkles may not necessarily also increase life expectancy. I am not too certain about this point, but it may be another caveat to have in mind.
To conclude: I would certainly not advise you try and get these drugs to test it out yourself, but I’m definitely looking forward to see a larger trial!