HSA | FSA CARDS ARE NOW ACCEPTED

Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

How SHROOM3 and rs13146355 Affect Magnesium Balance

Magnesium is an essential mineral involved in more than 300 biochemical processes, including muscle and nerve function, energy production, blood sugar regulation, and bone and heart health. The SHROOM3 gene helps shape kidney development and function. Because kidneys control how minerals are filtered, reabsorbed, and excreted, genetic differences in SHROOM3 can change how your body retains magnesium. The rs13146355 variant in SHROOM3 has been linked to differences in serum magnesium levels.

Why this matters

  • Too little magnesium can cause muscle cramps, fatigue, sleep problems, and worse long-term metabolic and bone health.
  • Too much magnesium, usually from supplements or poor kidney clearance, can cause diarrhea, low blood pressure, nausea, and in severe cases irregular heartbeat and muscle weakness.
  • Your genetic makeup at rs13146355 can shift where you sit on the spectrum of magnesium balance by influencing kidney handling of the mineral.

Practical actions you can take

  • Prioritize magnesium-rich whole foods: leafy greens, nuts and seeds, legumes, whole grains, dark chocolate, and avocados.
  • Be cautious with high-dose magnesium supplements, particularly if you have any kidney disease, take medications that affect the kidneys, or experience symptoms of excess magnesium.
  • Ask your healthcare provider about monitoring if you have concerns: serum magnesium, serum creatinine and estimated glomerular filtration rate (eGFR), and when appropriate a spot or 24-hour urine magnesium test.
  • Keep other lifestyle factors in mind: maintain good hydration, manage blood sugar, limit excessive alcohol, and review medications that affect magnesium with your clinician.
Two effect alleles (AA at rs13146355)

The AA genotype means you carry two copies of the effect allele. This genotype is associated with higher serum magnesium levels. Variations in SHROOM3 can alter kidney development and function, potentially making the kidneys more likely to retain magnesium in the bloodstream.

What this can mean for you

  • You may have a tendency toward higher serum magnesium compared with people who do not carry the effect allele.
  • Higher magnesium from genetic retention is often subtle and may not cause symptoms, but it can increase risk of side effects from extra magnesium intake.

Diet and supplements

  • Emphasize magnesium-rich foods rather than high-dose supplements: spinach, Swiss chard, almonds, pumpkin seeds, black beans, quinoa, and dark chocolate in moderation.
  • If considering a magnesium supplement, choose a low to moderate dose and discuss with your healthcare provider first. Forms such as magnesium glycinate or citrate have different absorption and tolerability profiles.
  • Avoid combining multiple magnesium-containing products (for example, laxatives, antacids, and supplements) without clinical guidance.

Tests and monitoring

  • Consider checking serum magnesium periodically if you take supplements or have symptoms such as persistent nausea, low blood pressure, or unusual muscle weakness.
  • Check kidney function (serum creatinine and eGFR) with your provider before starting supplements because impaired kidney function increases the risk of magnesium accumulation.

Lifestyle tips

  • Stay well hydrated and maintain a balanced diet to support renal health.
  • Avoid excessive alcohol, which can affect magnesium balance and kidney function.
  • Review any prescription or over-the-counter medicines with your clinician that may raise magnesium levels or affect kidney clearance, such as certain antacids and some blood pressure medicines.
One effect allele (AG at rs13146355)

The AG genotype means you carry one copy of the effect allele. This genotype is associated with a slightly higher tendency toward elevated serum magnesium compared with non-carriers, likely due to modest changes in kidney handling of magnesium.

What this can mean for you

  • A modest genetic tendency to retain more magnesium. For most people this will not cause symptoms.
  • Effects are typically smaller than with two effect alleles but worth noting if you use magnesium supplements or have kidney concerns.

Diet and supplements

  • Favor magnesium-rich whole foods: kale, almonds, sesame seeds, lentils, brown rice, and avocado.
  • If you choose to supplement, use conservative dosing and check with your healthcare provider. Avoid high-dose or multiple magnesium-containing products without guidance.

Tests and monitoring

  • Consider baseline serum magnesium and routine kidney function checks if you take supplements or have related symptoms.
  • Discuss any unusual symptoms such as persistent diarrhea, lightheadedness, or muscle weakness with your clinician promptly.

Lifestyle tips

  • Support kidney health through good hydration, balanced blood sugar, regular physical activity, and limiting excessive alcohol.
  • Keep a medication list available for your clinician to evaluate interactions that may affect magnesium.
No effect alleles (GG at rs13146355)

The GG genotype means you carry two copies of the non-effect allele. This is associated with standard or typical magnesium processing by the kidneys, without the genetic predisposition toward higher serum magnesium seen with the effect allele.

What this can mean for you

  • Your kidneys are expected to handle magnesium in a typical way compared with the general population.
  • Maintaining dietary intake and monitoring for symptoms if you use supplements is still important, but your genetic risk for magnesium accumulation is lower.

Diet and supplements

  • Maintain a varied diet rich in magnesium-containing foods to support overall health.
  • Supplementation may be appropriate if dietary intake is low, with guidance from your healthcare provider. Start with recommended daily amounts and avoid megadoses.

Tests and monitoring

  • Routine monitoring is not usually necessary solely because of genotype. Testing is recommended if you have symptoms, kidney disease, or if you take medications that affect magnesium.

Lifestyle tips

  • Healthy lifestyle habits that support kidney and metabolic health apply to everyone: hydration, exercise, balanced diet, and limiting high-risk substances.

When to talk with your healthcare provider

  • If you take magnesium supplements or multiple products that contain magnesium, especially in high doses.
  • If you have known kidney disease or risk factors for kidney dysfunction such as diabetes or long-term use of certain medications.
  • If you experience symptoms that could indicate too much magnesium: nausea, flushing, low blood pressure, drowsiness, muscle weakness, or irregular heartbeat.
  • If you are pregnant or breastfeeding and considering supplements.

Final notes and disclaimer

This information from PlexusDx is educational and intended to explain how genetic variation in SHROOM3 may influence magnesium balance. PlexusDx does not provide medical advice. Always consult your healthcare provider before making changes to supplements, medications, or testing based on genetic information. Your provider can interpret these results in the context of your overall health, clinical history, and current medications.

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:

Frequently Asked Questions About Magnesium and SHROOM3 rs13146355

How does the SHROOM3 rs13146355 variant affect magnesium balance?

The SHROOM3 gene helps shape kidney development and function, and your kidneys control how magnesium is filtered, reabsorbed, and excreted. The rs13146355 variant has been linked to differences in serum magnesium levels, meaning your genetic makeup may shift your tendency toward higher or more typical magnesium balance.

What should I do if my rs13146355 results suggest higher serum magnesium?

If you have one or two copies of the effect allele (AG or AA), you may have a modest tendency toward elevated serum magnesium because of differences in kidney handling. To support safe balance, prioritize magnesium-rich whole foods, use conservative doses if you choose supplements, avoid combining multiple magnesium-containing products without guidance, and talk with your healthcare provider about monitoring if you take supplements or have symptoms of excess magnesium.

When is magnesium testing recommended for rs13146355?

Testing is most useful if you take magnesium supplements or multiple magnesium-containing products, have kidney disease or risk factors for kidney dysfunction, or experience symptoms that could indicate too much magnesium (such as nausea, low blood pressure, drowsiness, muscle weakness, or irregular heartbeat). Your clinician may consider serum magnesium, kidney function tests (serum creatinine and eGFR), and in some cases a spot or 24-hour urine magnesium test.

What tests can help me learn more about Magnesium and SHROOM3 rs13146355?

The Optimal Diet and Weight Loss Genetic Test delivers over 295 genetic insights related to nutrition response, body composition, metabolism, and fitness. The Diet and Nutrition Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.