The idea is to inhibit mtor which regulates a lot of processes in the body that affects aging. The immunosuppressant effects are a side-effect.

If it works? It was promising but latetly it looks more unlikely.

Better thought of as an immune modulator than suppressant. Ultimately it’s a blunt tool when we lack more specific agents. Yes, it will have risks including infection, but the benefits may (or may not) outweigh the risks.

> isn’t it a bit counter productive for old people that tends to be weaker?

Not if it’s running around fighting imaginary worms and generally inflaming everything.