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SLC18A1 (VMAT1) rs1390938: What This “Neurotransmitter Packaging” Gene May Mean for Mood, Motivation, and Stress Balance

SLC18A1 encodes VMAT1 (vesicular monoamine transporter 1), a protein with a deceptively simple job that matters a lot for everyday brain and body function. VMAT1 helps “package” key monoamine neurotransmitters into tiny storage bubbles (vesicles) inside cells. These monoamines include dopamine, norepinephrine, epinephrine, and serotonin. Once packaged, they can be stored and released in a controlled, well-timed way.

That packaging step supports healthy monoamine signaling, which is closely tied to mood stability, motivation and reward sensitivity, stress response, and overall mental energy. VMAT1 is expressed in the brain and in endocrine tissues, and it also contributes to serotonin handling in the gut. Because monoamines influence how we feel and function day to day, SLC18A1 has been studied in relation to psychiatric traits, including mood- and anxiety-related outcomes, and alcohol-related patterns.

Why “Packaging” Neurotransmitters Matters

It is easy to focus on making neurotransmitters, but storage and release are just as important. Think of VMAT1 as part of a distribution system. If packaging is efficient, monoamines can be stored and released smoothly. If packaging is less efficient, monoamine availability may be lower or less steady, especially during periods of higher demand, such as chronic stress, sleep loss, heavy caffeine use, or alcohol exposure.

Monoamine signaling is not only about the brain. Because VMAT1 is also active in endocrine tissues and gut serotonin-producing cells, everyday habits that affect stress hormones, digestion, sleep quality, and inflammation can also shape how these systems feel in real life. Genetics may influence tendencies, but your routine often determines whether those tendencies show up as noticeable symptoms.

The rs1390938 (Thr136Ile) Variant: What Research Has Explored

The rs1390938 (Thr136Ile) variant is considered functional in lab studies, and population studies have connected it to differences in affect and to anxiety- and alcohol-related outcomes. This has led researchers to explore whether monoamine “packaging efficiency” may contribute to how resilient someone feels under stress.

In the research landscape described here, rs1390938 has been commonly studied and has been linked in some studies to higher VMAT1 activity and, in some samples, a lower risk of several mood-, anxiety-, and alcohol-related disorders. At the same time, some reports interpret an “effect allele” as being associated with reduced VMAT1 transport efficiency, which could mean slightly lower monoamine availability. In practical terms, the key takeaway is that this variant has been studied for meaningful differences in monoamine transport, and the real-world impact may depend heavily on sleep, stress load, and substance exposure.

How to Think About Your Result

Your report may present rs1390938 in a “0/1/2 effect allele” format. That format helps translate a genetic result into a simple, consistent framework. Below is the typical interpretation structure used in the report language:

2 effect alleles: GG

You have the GG genotype for rs1390938, which means you carry two copies of the effect allele. In the interpretation provided, this pattern is associated with reduced VMAT1 transport activity. Lower packaging efficiency may lead to lower monoamine availability and subtle differences in dopamine-related traits such as motivation, reward sensitivity, stress response, and mood balance.

Practical focus: Consistency tends to matter most. Steady protein intake, stable blood sugar, and limiting alcohol can reduce the day-to-day “load” on monoamine systems. Because monoamine signaling is highly influenced by sleep, stress, and substance exposure, supportive habits can make a noticeable difference.

1 effect allele: GA

You have the GA genotype for rs1390938, which means you carry one copy of the effect allele. With one effect allele, VMAT1 transport efficiency may be slightly reduced compared with AA. This could modestly influence monoamine availability and traits such as reward sensitivity, stress reactivity, and mood regulation.

Practical focus: Effects may be subtler and more dependent on sleep and stress. Diet works best paired with consistent sleep, regular movement, and basic stress management.

0 effect alleles: AA

You have the AA genotype for rs1390938, which means you carry two copies of the non-effect allele. This pattern is generally consistent with more typical VMAT1 transport activity, supporting balanced monoamine signaling involved in mood, motivation, reward processing, and stress response.

Practical focus: Even with typical transport activity, lifestyle habits still strongly shape how you feel. A steady routine supports cognition, motivation, and stress resilience across all genotypes.

Diet Recommendations for Monoamine Balance

A practical nutrition strategy is to support steady monoamine production and reduce lifestyle inputs that can destabilize these systems. Start with consistent protein intake, especially earlier in the day, to provide amino-acid building blocks used upstream in monoamine synthesis. Tyrosine and phenylalanine support catecholamines (dopamine, norepinephrine, epinephrine), and tryptophan supports serotonin.

Build each meal around a protein anchor, then add fiber-rich plants and healthy fats for steadier energy and more stable blood sugar. When blood sugar swings are frequent, some people notice more cravings and “reward chasing” eating patterns, especially during an afternoon or evening crash. A steadier pattern can support more consistent motivation and mood.

  • Protein anchors: eggs, fish, poultry, Greek yogurt or cottage cheese, tofu or tempeh, beans or lentils
  • Fiber-rich plants: vegetables, berries, legumes, oats, intact whole grains
  • Healthy fats: extra-virgin olive oil, nuts, seeds, avocado
  • Smart structure: if you are prone to mood swings or stress eating, avoid long gaps without food and use a structured snack (protein plus fiber) to prevent a late-day crash

Gut-Friendly Nutrition and Serotonin Handling

Because VMAT1 is expressed in serotonin-related gut cells, gut-friendly habits may be relevant for overall serotonin handling. If constipation or GI discomfort tracks with mood, consider whether your daily pattern supports regularity and comfort.

  • Fiber diversity: beans, lentils, oats, vegetables, berries
  • Fermented foods (if tolerated): yogurt or kefir, kimchi, sauerkraut
  • Hydration: adequate fluids can support digestion and comfort

Alcohol is worth special attention. This variant has been studied in relation to alcohol-use patterns, and alcohol can destabilize sleep and next-day mood. If you notice mood dips, higher anxiety, or lower motivation after drinking, reducing alcohol can be a high-impact step regardless of genotype.

Supplement Ideas to Support “Upstream” Neurotransmitter Needs

There is not a supplement that selectively “turns up” VMAT1 safely for everyone. The most evidence-aligned approach in this framework is to support the upstream pieces that influence monoamine availability: nutrient sufficiency, sleep quality, inflammation balance, and stress physiology.

  • Omega-3s (EPA/DHA): a strong baseline option for brain health, especially if you do not eat fatty fish regularly
  • Magnesium (often glycinate in the evening): commonly used when stress, muscle tension, or poor sleep quality are present
  • Foundational coverage: if diet consistency is low, a moderate-dose B-complex or quality multivitamin may help cover basic cofactors without megadosing

Because monoamine synthesis depends on multiple vitamins and minerals, it is often more effective to check for common deficiencies than to guess. With a clinician, consider labs that frequently relate to low mood, low drive, or brain fog: iron and ferritin, vitamin B12 and folate, vitamin D, and thyroid markers.

If you are considering serotonin-precursor supplements (such as 5-HTP) or dopamine-precursor products (such as mucuna or L-DOPA), treat those as clinician-guided. They can interact with medications and may be inappropriate for some psychiatric histories.

Safety note: If you take antidepressants, stimulants, or sedatives or sleep medications, or if you have bipolar-spectrum symptoms, review supplement choices with a clinician to reduce the risk of interactions or mood destabilization.

Lifestyle Recommendations: The Highest-ROI Levers

When a gene influences how monoamines are stored and released, lifestyle habits that stabilize monoamine demand often deliver the biggest real-world payoff. These are the “big three” in the report framework: sleep consistency, regular exercise, and stress management.

Sleep consistency: Keep a stable wake time, get morning light exposure, and protect a wind-down window at night. Dim lights and screens, avoid heavy meals close to bedtime, and be cautious with alcohol late in the day. Sleep loss increases stress reactivity and makes dopamine- and serotonin-driven regulation (impulse control, optimism, motivation) harder, regardless of genotype.

Exercise as a monoamine stabilizer: A mix of moderate aerobic activity (brisk walking, cycling, swimming) and resistance training supports mood and stress resilience through multiple pathways. If motivation is low, use a minimum-effective plan: 10 minutes counts, then build gradually. Consistency is the goal. Overtraining can backfire by increasing fatigue and stress hormones, which can worsen mood and sleep.

Daily downshifts for stress: Chronic stress increases monoamine turnover and can leave you feeling “flat” or reactive. Build a repeatable downshift you can do most days: 5 to 10 minutes of slow breathing, a short walk outside, journaling, or mindfulness practice. If nicotine, high-dose caffeine, or alcohol are part of your routine, consider targeted reductions. These can hijack monoamine circuits and disrupt sleep, and rs1390938 has been studied in relation to mood and alcohol-use outcomes in longitudinal samples.

When to Consider Professional Support

If symptoms such as persistent low mood, anxiety, or loss of motivation are significant, professional support (therapy and medical evaluation) can be high value. Genetics can shape susceptibility, but environment, sleep, stress load, medications, and health conditions often drive the day-to-day outcome. A clinician can also help evaluate whether nutrient deficiencies, thyroid issues, iron status, or other factors are contributing to how you feel.

Educational information only; not medical advice. Genetics influence tendencies, but sleep, stress, nutrition, exercise, medications, and overall health typically have a larger impact on daily mood and motivation than any single variant.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report: