I think the study quoted above is noting the similar behavior of many medications and compounds, including the Viagara-type pill Sildenafil, which is a vaso-dilator, statins (like simvastatin) and even blood pressure drugs (like amlodipine) versus a supplement like NMN.
Given the choice of all these types, I'd lean toward the use of a supplement.
Resveratrol 400mg since June 2019; 600mg since October 1; 800mg since January 2020
NMN Sublingual 250mg since june 2019 500mg since September 2019
NAD+ Nasal, appx 100mg per day since September 2019; 200mg per day beginning mid November
In this paper they describe a supplementation regiment that consists of NR (before the days of NMN being readily available) to up regulate mitochondria in the liver, L-Carnitine to accelerate fat transport to the mitochondria to be burned as fuel, and Serine and NAC to combat the increase in reactive oxide species created by the high fat burning liver mitochondria.
It is sort of a one-two-three punch to reduce fat deposits in the liver. At least it works for mice!
I have been taking this regiment daily for the past couple years. No ill effects, but I haven't had my liver fat tested in a while.