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The SLC18A1 rs1390938 (VMAT1) Variant and Monoamine Balance: What Your Genotype May Mean for Stress Resilience, Energy, and Mood

Your brain and body rely on a steady supply of chemical messengers called neurotransmitters. A key group of these messengers - called monoamines - includes norepinephrine, epinephrine, dopamine, and serotonin. They help shape everyday experiences like alertness, attention, motivation, stress response, mood stability, and even how steady your energy feels across the day.

The SLC18A1 gene encodes VMAT1 (vesicular monoamine transporter 1), a “packaging” protein that loads monoamine neurotransmitters into storage vesicles inside cells. Think of VMAT1 as part of the system that prepares neurotransmitters for controlled release. When packaging is efficient, signaling can be steadier and more predictable. When packaging is less efficient, signaling may be less stable - especially during high-demand situations like stress, poor sleep, or inconsistent eating patterns.

What VMAT1 Does and Why It Matters

VMAT1 helps move monoamines - especially norepinephrine, epinephrine, dopamine, and serotonin - into vesicles so they can be stored and released in a controlled way. This matters because neurotransmitter signaling is not just about how much you make, but how consistently you can store and release it. VMAT1 is expressed in the brain and in endocrine tissues, including areas tied to stress physiology. VMAT1 also contributes to serotonin handling in the gut, which is one reason gut patterns and stress physiology can show up together in day-to-day energy, mood stability, and brain fog.

Norepinephrine is especially relevant when talking about VMAT1. It supports alertness, attention, stress resilience, and energy regulation. When norepinephrine signaling feels “steady,” people often describe more consistent focus and fewer crashes. When signaling is less stable, some people notice a “wired then drained” pattern, more sensitivity to stress, or mood variability - especially when lifestyle inputs (sleep, meals, and stress load) are inconsistent.

The rs1390938 Variant: A Functional Change in VMAT1 Activity

One commonly researched SLC18A1 variant is rs1390938 (Thr136Ile). This SNP has been studied in relation to VMAT1 transport efficiency and has also shown associations in research with mood and psychiatric traits. In some studies, higher VMAT1 activity has been linked to lower risk of several anxiety-, affective-, and alcohol-related outcomes compared with lower-activity patterns. However, individual outcomes vary widely, and day-to-day habits can meaningfully shape how these pathways feel in real life.

Practical Steps for Everyone: A “VMAT1-Friendly” Foundation

Regardless of genotype, the most helpful strategy is to support stable monoamine signaling by keeping blood sugar steady, supporting mitochondrial energy, lowering inflammation, and maintaining a gut pattern that supports healthy serotonin handling. A practical template is Mediterranean/MIND-style eating: vegetables at most meals, berries several times per week, legumes and whole grains for fiber, olive oil, nuts and seeds, and fish - while limiting ultra-processed foods and frequent high-sugar snacks that can trigger energy crashes and irritability.

  • Build steady meals: Combine protein + fiber + slow carbs to avoid sharp spikes and dips in energy.
  • Prioritize protein at breakfast: A consistent morning protein anchor can support steadier focus and fewer mid-morning crashes.
  • Use fiber as a “stability tool”: Aim for a high-fiber pattern to support gut health and more even energy.
  • Be thoughtful with alcohol: Keeping alcohol modest (and away from bedtime) is a high-ROI move for mood stability, sleep quality, and next-day cognition.

Supplements and Nutrients to Consider (Steady Support, Not Overdrive)

For VMAT1-related patterns, supplements are most useful when they improve sleep and stress recovery, reduce inflammatory load, and correct common nutrient gaps that can look like mood or attention issues. Many people start with foundations that have a strong risk/benefit profile, especially when diet quality is inconsistent.

  • Omega-3s (EPA + DHA): Consider if you do not eat fatty fish 2–3 times per week.
  • Magnesium: Often used in the evening (many people prefer glycinate at night) to support relaxation and sleep quality.
  • Vitamin D: Consider when sun exposure is low, ideally guided by labs.

If symptoms like fatigue, brain fog, or mood volatility are present, labs-first essentials are often the biggest win. Consider discussing B12, folate, ferritin/iron status, and (when relevant) thyroid markers with a clinician, because deficiencies or hormonal dysregulation can feel like “neurotransmitter imbalance,” and correcting them can produce the most reliable improvement.

Because monoamine-related genes have been studied in psychiatric vulnerability contexts, it is wise to avoid a “kitchen sink” approach that stacks multiple neurotransmitter-active supplements at once - especially for people with a personal or family history of bipolar disorder, severe anxiety, or psychosis-spectrum symptoms. If you want a gentle add-on for calm focus or mental energy, many people trial one option at a time (for example, L-theanine for smoother calm-focus or creatine monohydrate for mental energy buffering) for 3–6 weeks while tracking sleep quality, irritability, focus stamina, and crash frequency.

If you are considering serotonin precursors (like 5-HTP) or stimulating adaptogens, it is safer to do so with clinician guidance. With monoamines, “more” is not always better.

Genetic Interpretations for rs1390938 (SLC18A1 / VMAT1)

2 effect alleles: GG

You have the GG genotype for rs1390938 (SLC18A1/VMAT1), which means you carry two copies of the effect (“G”) allele. This variant is associated with reduced VMAT1 monoamine transport efficiency, which can lower how effectively key neurotransmitters - especially norepinephrine, dopamine, and serotonin - are packaged into vesicles for steady storage and release. Because norepinephrine supports alertness, attention, stress resilience, and energy regulation, less efficient VMAT1 function may contribute to less stable monoaminergic signaling.

In research, SLC18A1 variants that reduce monoamine transport have been linked to psychiatric vulnerability, including associations with bipolar disorder and schizophrenia-related traits in some studies. This does not mean you will develop any condition, but it does make lifestyle consistency especially valuable.

Recommendations

  • Stabilize blood sugar: Limit frequent high-sugar snacks and refined carbs alone. Pair carbs with protein and fiber.
  • Use a protein-forward breakfast: Aim for 25–35 g protein at breakfast (examples include eggs, Greek yogurt, or tofu) plus berries and chia.
  • Anchor fiber twice daily: Add beans, lentils, oats, chia, or flax to support gut patterns and steady energy.
  • Support sleep and downshifting: Keep a consistent wake time, protect a wind-down routine, and limit caffeine earlier in the day (a common cutoff is 8+ hours before bed).
  • Be careful with “stimulating stacks”: Avoid stacking many neurotransmitter-active supplements at once. Trial one at a time and track your response.
  • Keep alcohol modest: Alcohol can disrupt sleep architecture and next-day cognition, which can amplify mood variability and brain fog.
1 effect allele: GA

You have the GA genotype for rs1390938 (SLC18A1/VMAT1), which means you carry one copy of the effect (“G”) allele. Relative to AA carriers, this genotype may be associated with somewhat reduced VMAT1 transport efficiency, which can modestly affect how consistently monoamines - especially norepinephrine, dopamine, and serotonin - are stored and released.

Because these neurotransmitters shape attention, mood stability, stress response, and energy regulation, GA carriers may have a slightly higher tendency toward monoamine imbalance in certain contexts, though individual outcomes vary widely. The biggest lever is consistency: sleep, meals, movement, and stress recovery routines.

Recommendations

  • Eat for steadier energy: Use slow carbs (oats, quinoa, sweet potato, fruit) and avoid refined carbs alone when possible.
  • Keep meals predictable: Consistent meal timing and composition can reduce “wired then drained” patterns.
  • Support gut–brain balance: Target 25–40 g fiber per day and include fermented foods if tolerated (yogurt, kefir, kimchi, sauerkraut).
  • Use exercise as a stabilizer: Aim for 150–300 minutes/week of Zone 2 cardio plus 2–3 resistance sessions to support stress resilience and sleep depth.
  • Choose gentle supplements first: Prioritize basics like omega-3s and magnesium before experimenting with more activating options.
0 effect alleles: AA

You have the AA genotype for rs1390938 (SLC18A1/VMAT1), which means you carry two copies of the non-effect (“A”) allele. This variant has been linked to higher VMAT1 monoamine transport activity, supporting efficient “packaging” of neurotransmitters like norepinephrine, dopamine, and serotonin into vesicles for controlled storage and release.

Because norepinephrine helps regulate alertness, attention, stress resilience, and energy, more efficient VMAT1 function may support steadier monoaminergic signaling. In some studies, the A allele has also been associated with a lower risk of several anxiety-, affective-, and alcohol-related outcomes compared with lower-activity variants.

Recommendations

  • Protect the advantage with consistency: Even with efficient packaging, poor sleep and high stress can still destabilize mood and attention.
  • Maintain a nutrient-dense baseline: Continue a whole-foods pattern with vegetables, fiber, healthy fats, and adequate protein.
  • Keep alcohol and late caffeine in check: Sleep disruption is a fast way to reduce next-day focus and increase irritability in anyone.
  • Stay routine-friendly: Regular movement, regular sleep timing, and predictable meals support long-term cognitive performance.

Lifestyle Recommendations: Highest ROI for VMAT1 Pathways

VMAT1 supports reliable monoamine release, so your lifestyle goal is predictable inputs that keep norepinephrine, dopamine, and serotonin signaling steady: regular sleep, regular movement, and regular stress downshifts.

  • Sleep timing: Keep a consistent wake time, get bright light within an hour of waking, and protect a 60–90 minute wind-down with lower stimulation.
  • Caffeine timing: Limit caffeine to earlier in the day; fragmented sleep can worsen anxiety, irritability, and brain fog regardless of genotype.
  • Exercise as a “monoamine stabilizer”: Aim for steady weekly movement (Zone 2 cardio plus resistance training) to support stress resilience, metabolic flexibility, sleep depth, and inflammation balance.
  • Daily downshift: Add 5–10 minutes of a parasympathetic practice (slow breathing, mindfulness, gentle yoga, or a walk without your phone).
  • Environmental guardrails: Make routines easier - phone out of the bedroom, scheduled breaks, fewer late-night decisions, and repeatable meal templates.

When to Talk to Your Healthcare Provider

If you have persistent concerns about mood stability, anxiety, sleep disruption, attention changes, or energy crashes, talk with a healthcare provider. They can help interpret symptoms in context, consider labs that commonly affect energy and mood (such as B12, folate, ferritin/iron status, vitamin D, and thyroid markers when relevant), and guide safer choices if you are considering neurotransmitter-active supplements - especially if there is a personal or family history of bipolar disorder, severe anxiety, or psychosis-spectrum symptoms.

PlexusDx does not provide medical advice. This information is educational and intended to help you understand how SLC18A1 (VMAT1) genetics may relate to neurotransmitter balance, stress resilience, and steady energy. Always consult your healthcare provider before making changes to your diet, supplement routine, or exercise plan, or if you have concerns about your health.

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: