N-Acetyl-L-Tyrosine is much stronger than L-Tyrosine. In fact it may act differently. It can be used up to 400 mg per day or so depending on body weight. Be careful it has a strong dose dependent response. I use it as a good get up and go stimulant instead of coffee. It reduces anxiety as well. It has a strong peak and will return cognitive, social and sensory levels to normal very gently. If you take much more it can cause hyperactivity or sleep. Frankly 5-HTP and L-Tyrosine did nothing for me even at several times the recommended doses.
I would recommend sunlight (vit. D), Taurine, a good diet and removing foods that promote immune reactions and swelling in the gut. 70% of the serotonin in your body is produced in the gut - not the brain! Disbiosis and bad gut immune reactions (cheese/milk [casein], wheat [gluten], eggs, coffee, corn syrup, etc..) can keep a good person feeling absolutely miserable.