It ended up not being the L-tryptophan, but the impurities in some of the supplements that contained it.
So for years L-trytophan got a bad name.
I don't know enough about Omega-3's and their manufacturers, but it could be that Omega-3 is fine, it's just that it's combined with crap.
The supplement industry refuses to be regulated. Every study that has come out in the past few years basically says supplements are bogus. My guess is that well made supplements can provide benefits, but there is so much junk on the market that the average effect is either neutral or negative.
Not that the FDA is such a great organization, but if the few quality supplement manufacturers would agree to be regulated by the FDA and provide decent products at reasonable prices they might start getting good press and good test results and distance themselves from the charlatans that cry 'free market, free market' whenever anyone challenges the safety and effectiveness of their products.