I’ve used it. It works with no side effects.
sure if you have the money and the engine is in good condition otherwise replace the head gasket. There is potentially and likely reasons not to replace and k seal would be your best bet.
KSeal is real deal it works. I have used it on a Tundra and it totally solved the problem. No bubbles coming though at all normal temperatures.
https://www.kseal.com/
I just bought mine. A major reason was the ability to go naked. In the three weeks I’ve had it the freedom panels have been off. Once it gets warmer the doors and back roof will come off. So far I love this thing.