by Matt Weik, BS, CSCS, CPT, CSN
L-tyrosine, or tyrosine, is a non-essential amino acid made naturally in our body from the essential amino acid phenylalanine. It plays a crucial role in various bodily functions, such as creating enzymes, proteins, and muscle tissue.
Tyrosine helps produce neurotransmitters, like epinephrine, dopamine, and norepinephrine, that affect our mood, alertness, and memory. It also plays a part in the production of melanin, which is the pigment that gives color to hair and skin, and thyroid hormones, which regulate metabolism.
Tyrosine can be found in many foods, such as cheese, eggs, chicken, pork, beef, fish, soybeans, beans, and nuts. It can also be found as a dietary supplement, which is mostly used to improve attention and focus.
In this article, we will dive deeper and learn many more aspects of tyrosine supplements to help you better understand the benefits as well as whether they can help improve cognitive performance in endurance sports.
Disclaimer: This article is for informational purposes only and is not meant to treat or diagnose any condition. It is recommended that you speak with your doctor before starting any exercise program, changing your daily nutrition, or adding any supplements to your regimen.
What Does Tyrosine Do?
Tyrosine, also known as L-tyrosine, is one of 20 amino acids that form proteins. The body makes tyrosine from phenylalanine, another amino acid, so it’s considered “non-essential.” You don’t need to get it from food, but eating more can be beneficial.
L-tyrosine offers several potential benefits. It may help fight fatigue, depression, and poor cognitive function. Some research suggests it might also aid in weight management.
Tyrosine produces two important brain chemicals: dopamine and norepinephrine (also called noradrenaline). The amount of tyrosine you consume from food or supplements affects the production of these chemicals. Other nutrients like folate, B vitamins, copper, and magnesium help turn tyrosine into dopamine and norepinephrine.
3 Benefits of Tyrosine
Below are some potential benefits of tyrosine and the use of tyrosine supplements.
1. Improves cognitive performance
Stressful situations can quickly deplete catecholamine neurotransmitters like norepinephrine and epinephrine (adrenaline), which are vital for cognitive function. This depletion negatively impacts decision-making and working memory. However, research suggests that tyrosine, as a precursor to these neurotransmitters, may help prevent their reduction and improve cognitive performance under extreme stress.
A review of 15 studies supports this idea, indicating that increased tyrosine intake may counteract the cognitive decline associated with physical and mental stress. Working memory and information processing improvements were observed after just one dose of tyrosine.
In a randomized controlled trial involving 80 participants, the effect of tyrosine on stress markers and cognitive performance was tested after a virtual reality (VR) active shooter drill. While tyrosine didn’t reduce stress markers, it did enhance cognitive performance. Participants showed better response times and decision accuracy, with fewer missed answers on a test measuring these outcomes.
These findings suggest that tyrosine may play a key role in maintaining cognitive function during high-stress situations, making it a potential aid for improving mental clarity when under pressure.
2. May help people with Phenylketonuria
Phenylketonuria (PKU) is a rare genetic disorder caused by a defect in the enzyme phenylalanine hydroxylase, which helps convert phenylalanine into tyrosine. Without this enzyme, phenylalanine builds up in the body, and people with PKU can become deficient in tyrosine, leading to behavioral issues.
While the primary treatment is a phenylalanine-restricted diet, some have explored tyrosine supplements to address the deficiency.
3. Weight loss
According to the University of Michigan Medicine, no studies show that L-tyrosine directly promotes weight loss. However, when combined with other fat-burning ingredients like cayenne, green tea, and caffeine, there’s some evidence of slight fat loss.
A 2007 study showed that overweight adults who took tyrosine with capsaicin, catechins, and caffeine experienced a modest weight reduction of about 0.9 kg.
As for weight gain, tyrosine doesn’t typically cause it. Although it may not reduce appetite or lead to weight loss, it has been shown to improve appetite, cognition, and exercise tolerance in individuals recovering from conditions like anorexia.
How Much Tyrosine Should You Take?
For most adults, the recommended daily intake of phenylalanine and tyrosine supplements combined is approximately 27 milligrams per kilogram (mg/kg) of body weight. This requirement increases to 33 mg/kg for children with phenylketonuria (PKU) and 36 mg/kg for pregnant individuals.
However, research suggests these increased amounts might still be insufficient during pregnancy.
A study examined aromatic amino acid requirements in healthy humans, indicating a potential need for higher intake in some instances.
Optimal protein synthesis occurs with a 60:40 ratio of phenylalanine to tyrosine, meaning adults should aim to consume roughly 10.8 mg of tyrosine per kilogram of body weight or 4.9 mg per pound. Most individuals naturally obtain enough tyrosine through their diet, making supplementation unnecessary for many.
Tyrosine supplement dosages used in studies vary significantly, ranging from fixed amounts of 2–20 grams to 25–150 mg/kg of body weight. That said, it’s important that we reiterate that it’s essential to consult a healthcare provider to determine the most appropriate dosage based on your individual health needs.
