HSA | FSA CARDS ARE NOW ACCEPTED

How the TH Gene Affects Brain Chemistry and Why It Matters

The TH gene encodes tyrosine hydroxylase, the enzyme that starts the cascade to make dopamine, norepinephrine, and epinephrine from the amino acid L-tyrosine. Because TH catalyzes the rate limiting step, small changes in its activity can shift how much dopamine and downstream catecholamines your brain produces. Catecholamine balance also depends on methylation pathways that help deactivate excess neurotransmitter. When methylation and cofactor supply are healthy, COMT and related systems help keep neurotransmitters at the right level for mood, motivation, attention, and stress resilience.

TH needs oxygen, iron, and tetrahydrobiopterin (BH4) to function. BH4 is regenerated by the biopterin pathway, which links directly to methylation efficiency. If TH function is altered by genetics, nutrient shortfalls, oxidative stress, or toxin exposure, dopamine production can change. That can show up as differences in motivation, focus, energy, and emotional stability.

What This Means for You

  • Higher TH activity can increase baseline dopamine synthesis but may raise demand for cofactors and resilience to stress.
  • Lower or typical TH activity keeps synthesis in a standard range but still relies on cofactor sufficiency and healthy methylation.
  • Supporting cofactors, protecting against oxidative stress, and reducing exposure to neurotoxic chemicals help keep catecholamines balanced.

Practical Steps: Diet, Supplements, Lifestyle, and Tests

Below are practical, consumer friendly recommendations you can discuss with your healthcare provider. PlexusDx does not provide medical advice. Always consult your healthcare provider before making changes to diet, supplements, or medications.

Diet

  • Include protein sources rich in tyrosine and phenylalanine such as lean poultry, fish, eggs, dairy, legumes, and nuts to support neurotransmitter precursors.
  • Eat iron-rich foods: red meat, poultry, seafood, beans, lentils, spinach, and iron-fortified grains. Combine plant iron with vitamin C containing foods for better absorption.
  • Choose antioxidant rich fruits and vegetables to help limit oxidative stress. Berries, citrus, leafy greens, and colorful vegetables are good options.
  • Include sources of healthy fats such as oily fish, avocado, and nuts to support overall brain health.
  • Limit or avoid cigarette smoke, excessive alcohol, and foods with high pesticide residues when possible.

Supplements to Consider

Discuss these options with your provider. Supplement needs vary by individual and should be chosen based on blood tests and medical history.

  • Iron when indicated by labs. Do not take iron supplements unless deficient, because excess iron can be harmful.
  • Vitamin C to support iron absorption and act as an antioxidant.
  • Vitamin D to support overall brain and immune health. Test levels prior to dosing.
  • BH4 supportive nutrients such as folate (methylfolate if appropriate), riboflavin (B2), niacin (B3), and pyridoxine (B6) as part of a B complex when indicated.
  • General antioxidants like vitamin E and polyphenol-rich extracts if recommended by your provider.

Lifestyle Recommendations

  • Manage stress through regular practices such as mindfulness, meditation, yoga, or breathwork. Chronic stress increases demand on catecholamine systems.
  • Prioritize sleep. Aim for consistent, restorative sleep to support neurotransmitter synthesis and methylation cycles.
  • Regular moderate exercise supports dopamine signaling and helps regulate mood and energy.
  • Avoid known neurotoxic exposures such as cigarette smoke and minimize contact with organophosphate pesticides by choosing lower-residue produce or using protective measures.
  • Limit stimulants and excessive caffeine which can alter catecholamine balance in some people.

Blood Tests and Monitoring

  • Ferritin and complete blood count to assess iron stores and rule out anemia.
  • 25-hydroxy vitamin D to check vitamin D status.
  • Homocysteine and a basic B-vitamin panel when methylation concerns are present.
  • Comprehensive metabolic panel and lipid profile as part of overall health monitoring.
  • Discuss urine or plasma catecholamine testing with your provider if there are significant symptoms of dysregulated catecholamine activity.

Genetic Interpretations for rs10770141

Two effect alleles (AA)

Genotype: AA means two copies of the effect allele and is associated with increased TH activity. This may raise baseline dopamine synthesis from L-tyrosine, which can be beneficial for motivation, focus, and drive under many conditions. Higher synthesis also increases demand for cofactors such as oxygen, iron, and BH4 and can increase vulnerability to stress induced dopamine depletion when cofactor supply or methylation capacity is limited.

Considerations:

  • Monitor iron and vitamin D status and address any deficiencies under medical guidance.
  • Support BH4 pathways with appropriate B vitamins and nutrients when recommended by a clinician.
  • Apply stress reduction practices to protect dopamine reserves during acute or chronic stress.
  • Avoid neurotoxic exposures like cigarette smoke and organophosphate pesticides to limit extra enzyme stress and oxidative damage.
One effect allele (AG)

Genotype: AG means one copy of the effect allele. This is linked to moderately increased TH activity compared to the non-effect genotype and may slightly enhance dopamine synthesis in normal conditions. With modestly increased TH activity, maintaining nutrient cofactors and minimizing oxidative stress helps sustain balanced neurotransmitter production.

Considerations:

  • Ensure adequate dietary iron with vitamin C to improve absorption.
  • Maintain healthy vitamin D levels and consider a balanced B complex if recommended.
  • Practice regular stress management and moderate exercise to support neurotransmitter regulation.
  • Reduce exposure to environmental toxins that can impair TH or increase oxidative burden.
No effect alleles (GG)

Genotype: GG means two copies of the non-effect allele and is associated with typical TH activity and standard dopamine synthesis rates. Your capacity for dopamine production is likely within the usual range. Even with typical function, TH still depends on cofactors and a healthy biopterin recycling pathway. Supporting these systems helps maintain stable catecholamine levels.

Considerations:

  • Focus on adequate nutrition, especially iron, vitamin C, and vitamin D.
  • Support overall methylation health with a balanced diet and consider B vitamin assessment if symptoms suggest methylation imbalance.
  • Maintain healthy lifestyle habits including sleep, exercise, and avoidance of neurotoxins.

Final Notes and Safety

This information is educational and intended to help you understand how variation in TH might influence neurotransmitter synthesis and wellness. PlexusDx does not provide medical advice. Always consult your healthcare provider or a qualified clinician before starting or stopping supplements, changing medications, or making significant lifestyle changes based on genetic results. Your provider can interpret these findings in the context of your medical history, symptoms, and appropriate laboratory testing.