Tyrosine is a non-essential amino acid which is a precursor to proteins vital to mental functions. When taken as a supplement it provides powerful nootropic benefits.
- Improves general cognitive performance, includes memory, problem-solving, energy, concentration, motivation 
- Reduces the effects of stress and fatigue
- Improves mood under extenuating circumstances such as loss of loved one, prolonged work, and sleep deprivation 
- Counteracts cognitive/physical performance impairment during periods of sustained work and sleep loss 
What Is Tyrosine?
Tyrosine is a non-essential amino acid that is used by cells to synthesize proteins. It was discovered in 1864 by the German chemist Justus von Liebig. He discovered it in a protein called “casein” found in certain cheeses. It is now known that Tyrosine can be found in many food products including meats, fish, nuts, beans, oats, wheat, and dairy products. It is also commonly sold and used as a supplement.
Tyrosine Dosage Information
The standard dosage for Tyrosine is between 500 – 1,500 mg per day. Generally, this is the equivalent of 1 – 3 capsules or tablets. To get the wanted effects it is best to take all the dosage all at once. You should never exceed 12,000 mg in a single day. When dosages are two high, Tyrosine is counterproductive and actually decreases levels of dopamine in the brain.
How Does Tyrosine Work?
Dopaminergic cells in the brain use the enzyme “tyrosine hydroxylase” (TH) to convert tyrosine to levodopa (L-DOPA). Levodopa is essential for your body’s production of the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline).  Levodopa itself is a drug used in the clinical treatment of Parkinson’s disease and dopamine-responsive dystonia.
The effects of Tyrosine stem directly from its ability to be converted in L-DOPA and its effect on neurotransmitter levels.
Safety and Side Effects of Tyrosine
Tyrosine is known to be safe when taken in doses of 150mg/kg (6,800mg for a 150lb person) per day for up to 3 months. Reported side effects include joint pain, heartburn, nausea, and headache. There is not enough information about Tyrosine to know if it is safe for children or pregnant women. You should also not take Tyrosine if you have an overactive thyroid or suffer from Graves disease. 
Because Tyrosine and Levodopa work through the exact same mechanism of action they should not be taken together. Taking them together can cause them to work against each other, decreasing their effectiveness. 
Below are some of the most commonly asked questions about Tyrosine.
Should I Use Tyrosine?
What Are Some Notable Studies on Tyrosine?
One study to take note of was conducted in 1999. This study aimed to monitor the effects of Tyrosine on a group of 21 during a demanding military combat training course. Ten subjects received daily doses of Tyrosine while the other cadets received a carbohydrate placebo. The cadets were assessed immediately prior to the combat course and on the 6th day of the course. The group that received the Tyrosine performed significantly better on a memory and a tracking test then the placebo group. The group supplied with Tyrosine also had lower blood pressure. No significant changes in mood were noted. The study concluded that Tyrosine “reduces the effects of stress and fatigue on cognitive task performance.” Another study conducted in 1995, looked at Tyrosine’s effects on sleep-deprived workers. Subjects were deprived of sleep for a single night and examined during an episode of continuous work. The subjects performed a batter of nine performance tasks and were asked to complete mood scales. Six hours into the experiment, half of the subjects received a 150mg/kg dose while the other half received a placebo. The subjects which received the Tyrosine dose performed significantly better on the tasks up to 3 hours after ingestion. The study concluded that Tyrosine proves useful in counteracting performance impairment during periods of sustained work and sleep-loss. 
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