It reduced the smoke a bit, but only to a small degree.
Maybe it can't do more depending on the internal damage of the engine, because when starting I had quite a lot of smoke.
The products of this company seem good

For valve stem seals that produced a little blue smoke only at startup and not while driving, as well as moderate oil consumption of 1 liter per 5000km in a 2009 Porsche Cayenne, it almost completely eliminated the blue smoke and reduced oil consumption by half

In vw golf gti
I added it to the oil which had been changed a few days before
It burns quite a bit of oil, emits white-blue smoke, and has a strong oil smell
On the first day, it significantly reduced the white smoke and smell
On the second day, after some kilometers, the white-blue smoke stopped by 90% and the burnt oil smell decreased by 90%

I don't know if it helps with oil consumption because I've done only a few kilometers
I will provide an update at 1000 km
For now, 5 stars

It did not have the desired result on a diesel engine after 2000 kilometers of use, it continued to burn oil, only the noise in the engine decreased

I used it in a Cinquecento 899 that was smoking and burning oil (about 1 liter per 1000 km). I added it after an oil change and after it burned about 300ml of oil (to add the entire quantity of the 300ml of the additive). I noticed less smoke from the exhaust and it seemed to burn less oil (half a liter per 1000 km from the change). However, I can't know if this is solely due to the additive or the different oil I used for the change. I will come back when I have more information.