Starting L-tyrosine at a low dose (250-500 mg) is advisable, especially when combined with caffeine or other stimulants.

“I would say you should also start with the lowest possible dose so for most people 250 to 500 milligrams is going to be a reasonable starting dose depending on your body weight smaller people start with 250 larger maybe 500 keep an eye on whether or not you're combining it with caffeine or with any other stimulants and keep in mind that again the bigger the peak in dopamine the bigger the trough in dopamine afterwards so pay attention to whether or not you experience a crash that same day or the next day”