For the longest time, people said to never pair the two because it would result in a ridiculous amount of hair loss that would continue for up to 16 months.
Sometime later, people claimed that this was simply an "old wives tale" and the combination wouldn't cause increase hair loss.
LETS CLEAR THIS UP.
Here's the answer -
NEVER PAIR FINASTERIDE WITH DECA.
When they are used concurrently, an interesting scenario unfolds; Finasteride is reduced via the 5AR enzyme to a metabolite, which is not as androgenic as DHT. In addition, the metabolite of Deca-Durabolin is less androgenic than the parent compound, which means that if your Finasteride is pre-occupied with the metabolite, Deca-Durabolin is more able to wreak havoc on the hairline.
So in short, the potential of Nandrolone for hair loss is much more than the less androgenic metabolite (DHN- dihydronandrolone), so it’s a safe bet to stay away from it completely.
I have experienced this personally, don't pair the two if you care about your hair.
I would say consider yourself lucky.
For those still want to prevent hair loss but want to use nandrolone (deca or npp) then RU58841 is an even more attractive option as you under no circumstance should pair finasteride/dutasteride with nandrolone imo.