Do you notice your energy lagging on a plant-based or low-protein diet? Do you feel sensitive to cold air or season changes? Do you struggle with focus, mood, motivation, or impulse control when life gets stressful? If so, your body may be running low on tyrosine—a key amino acid that fuels your thyroid, adrenals, and brain.

What is Tyrosine?

Tyrosine is a non-essential amino acid made from phenylalanine. Although the body can produce it, tyrosine reserves are easily depleted by stress, aging, low protein intake, or plant-based diets. Because it serves as a precursor to critical hormones and neurotransmitters, maintaining adequate levels is essential for healthy energy, mood, and cognitive function.

Precursor for Thyroid, Adrenals, and Neurotransmitters

Tyrosine is a critical precursor for thyroid and adrenal hormones, neurotransmitters and catecholamines such as dopamine, norepinephrine, epinephrine as well as enkephalins involved with pain signals. Tyrosine increases the availability of dopamine in your brain, sympathetic nervous system, and other tissues for mental function, focus, cognitive flexibility, body temperature, appetite regulation, and physical energy.

Tyrosine plays a substantial role in managing energy, stress, motivation, mood, metabolism, and even pain tolerance. Research also shows improvements in promoting calmness and controlling impulse behavior in various settings due to tyrosine’s enhancement of dopamine.

Reaction Times and Movement

Tyrosine may improve reaction times in older adults, helping with mental and physical activities and quick reactions. Tyrosine supports movement and posture due to its effect on catecholamine levels, especially dopamine. With increased age, walking and posture may become more challenging to healthfully maintain. Neurotransmitters synthesized from tyrosine are required for the neuromuscular connections and signals that allow movement and posture.

Stress Tolerance, Mood, Energy

When tyrosine stores have become depleted, you may experience lower body temperature, low blood pressure, reduced pain and stress tolerance, or have restless legs. Thyroid function may slow down. Depleted tyrosine levels lower the production of dopamine, affecting brain function and energy making you feel more fatigued, lethargic, withdrawn, cold, or have slower reaction times, movement and balance concerns.

The greatest improvement from tyrosine supplementation on cognitive function, mood, and focus occurs when your body is depleted due to stress, overdoing it, and lack of protein in the diet.

Tyrosine and Gut Microbiome

Tyrosine’s impact goes beyond cognitive function and stress tolerance. A new 2025 study evaluated tyrosine’s effects on behavioral and physiological changes using neurodevelopmentally challenged animal models. Results showed remarkable positive effects of tyrosine supplementation on the gut-brain connection, the gut microbiome, gut barrier, brain function, and protection of neurons in the hippocampus of the brain.

Results showed improvements with social communication and less repetitive behaviors. Furthermore, tyrosine protected the intestinal lining from damage while supporting the gut microbiome composition and function. These findings led the authors to suggest that dietary tyrosine may be helpful for supporting physical and behavioral challenges with neurodevelopment. 

Body Temperature Regulation

Fall temperatures are coming soon. As you feel the chill in the air, this places a higher demand on your body’s nervous system for tyrosine, dopamine and other neurochemicals to regulate body temperature. Tyrosine works with the sympathetic autonomic nervous system to cause vasoconstriction of blood vessels in the skin which minimizes heat loss from cold exposure. Research from a small randomized controlled trial showed improved tolerance for cold temperatures with tyrosine supplementation, especially in older adults.

Metabolic Speed and Thyroid

Tyrosine works with your thyroid gland and sympathetic autonomic nervous system to influence your metabolic speed. Tyrosine and iodine make T4 thyroid hormone, the most abundant thyroid hormone in the body. Inadequate dietary tyrosine or protein and/or iodine can lead to sluggish metabolism and dysfunctional thyroid hormone production. Fatigue, dry skin or hair, hair loss, depression, mental fog, cold temperature intolerance, constipation, and poor memory may result.

Dietary Sources of Tyrosine

The best food sources for tyrosine are animal proteins. Beef, pork, poultry, lamb, salmon, tuna, trout, eggs, cheese (Swiss, cheddar, mozzarella), and yogurt provide good amounts of tyrosine. Plant-based foods like seeds, nuts, beans, legumes, quinoa, oats, bananas, avocado, tofu and tempeh provide considerably smaller amounts of tyrosine.

A vegan or plant-based diet or other restrictive diets may lead to limited tyrosine intake thereby requiring supplemental support. Older adults may be more susceptible to lower tyrosine intake and dopamine levels due to age, diminished digestive capacity, and/or limited dietary intake. Other situations related to genetics can lead to poor tyrosine metabolism affecting neurological and endocrine function.

The absorption of tyrosine can be impaired by other amino acids in the diet. You may find it easier to take tyrosine supplements between meals for best results. 

Essential Nutrients for Tyrosine to Dopamine Conversion

Tyrosine metabolism also requires some nutrients to convert it into dopamine and catecholamines. These include iron, copper, folate, vitamin C, vitamin B3, B6 and s-adenosylmethionine (SAMe). Low levels of one or more of these nutrients may impair the end production and tissue levels of dopamine.

Nutritional Supplements

Tyrosine is essential for clear thinking, steady energy, thyroid health, and stress recovery. When your body’s stores run low—whether from stress, aging, or a low-protein diet—supplemental support can make a noticeable difference. Here are some excellent nutritional formulas to help you recharge your energy, sharpen focus, and feel your best.

Thyroid Helper contains l-tyrosine with selenium, manganese, and the adaptogenic herbs ashwagandha and gugulipid. This glandular-free formulation supports sluggish thyroid function. It is often taken with Adrenal Helper, Daily Energy Multiple Vitamin, and Iosol Iodine for foundational neuro-endocrine support.

Activator Plus contains phenylalanine which converts into tyrosine. It also contains a blend of antioxidants and trace minerals for mitochondria function, energy support, and liver detoxification. Activator Plus does not contain herbs, making it a great option for those who may be sensitive to various herbs.

Super Brain Booster contains n-acetyl-tyrosine, an easy to absorb, activated form of tyrosine. It can easily cross the blood brain barrier to support focus, alertness, motivation, and cognitive function while under stress. It also contains alpha-GPC, organic Bacopa extract, and phosphatidylserine for cognitive support and memory.

If you need some extra protein in your diet, consider Daily Protein Plus from grass-fed, pasture-raised Irish cows. It is an excellent source of complete amino acids without sugar, cholesterol, or lactose. It’s a great way to start the day, or whenever you need a protein boost!

Additional Resources

Body Temperature – Thyroid, Adrenals, or Something Else?

Thyroid Guide: Resources for Improving Thyroid Health Naturally

Protein is Essential for Thyroid Function. Are You Getting Enough?

Protein is Essential for Health: Are You Getting Enough?

What’s Your Iodine Status?