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.

Carnitine and the SLC22A5 Gene: What Your Genotype Means for Energy and Muscle Health

Carnitine is a key nutrient that helps move long-chain fatty acids into mitochondria, the cell’s energy centers. This process is especially important for tissues with high energy demand, like skeletal muscle and the heart. The SLC22A5 gene encodes the OCTN2 transporter, which transfers carnitine from the bloodstream into cells and helps the kidneys conserve carnitine. Variations in this gene can change how efficiently carnitine is handled, which may affect energy levels during stress, illness, very low-calorie intake, or intense exercise.

How carnitine affects health

  • Supports mitochondrial fatty acid oxidation and ATP production
  • Helps maintain muscle and cardiac energy supply under stress
  • Supports recovery and performance during endurance and resistance exercise
  • Depends on adequate dietary building blocks and cofactors for the body to synthesize and conserve carnitine

Dietary and lifestyle foundations to support carnitine function

Whether or not you carry a variant in SLC22A5, these practical strategies help maintain carnitine status and mitochondrial health:

  • Protein: Aim for consistent dietary protein to provide lysine and methionine, the amino acid precursors for endogenous carnitine synthesis. Good sources include red meat, poultry, fish, eggs, dairy, legumes, and tofu.
  • Carnitine-containing foods: Red meat and dairy contain preformed carnitine. Include these if tolerated and consistent with your dietary preferences.
  • Micronutrient cofactors: Ensure adequate vitamin C, iron, vitamin B6, vitamin B12, and niacin as they support carnitine synthesis and overall mitochondrial function.
  • Exercise: Combine regular aerobic conditioning and resistance training to enhance mitochondrial capacity and muscle energy utilization.
  • Sleep and stress: Prioritize 7 to 9 hours of quality sleep and stress-management techniques to reduce metabolic strain on energy systems.
  • Hydration and recovery: Maintain proper hydration and allow sufficient recovery after intense exercise to support muscle repair and metabolic balance.

When to consider testing or supplements

Carrying a variant does not mean you will develop a disorder. Most carriers do not. However, if you have unexplained fatigue, muscle cramps, exercise intolerance, or other symptoms suggesting impaired energy metabolism, consider discussing with your clinician:

  • Blood tests: plasma free and total carnitine, creatine kinase, basic metabolic panel, iron studies, B12 and folate, and thyroid function as part of an evaluation.
  • Supplement options: Under medical supervision, clinicians may consider L-carnitine supplementation, coenzyme Q10, or magnesium when deficiency or functional impairment is suspected.
  • Medication and medical history review: Some medications and medical conditions can influence carnitine levels; discuss these with your provider.
2 effect alleles — GG genotype (carrier of mutation associated with primary carnitine deficiency)

You have two copies of the effect allele for rs11568520 and are a carrier of a mutation associated with primary carnitine deficiency. Carriers may have reduced OCTN2 transporter efficiency, which can lower cellular carnitine uptake and kidney conservation, particularly during metabolic stress such as illness, prolonged fasting, or very intense training.

What this often means in day to day life:

  • Most carriers remain asymptomatic and do not develop overt carnitine deficiency.
  • You may be more vulnerable to low energy, muscle weakness, or exercise intolerance when under stress or during very low-calorie periods.

Practical recommendations:

  • Eat regular, protein-rich meals that include lysine and methionine sources: red meat, dairy, fish, poultry, eggs, legumes, and tofu.
  • Include carnitine-rich choices like lean red meat and dairy if compatible with your diet.
  • Optimize micronutrients: ensure sufficient vitamin C, iron, B6, B12, and niacin through food or supplements as advised by a clinician.
  • Follow a balanced exercise program combining aerobic and resistance training to support mitochondrial efficiency.
  • Prioritize 7-9 hours of sleep, stress reduction practices, and adequate hydration.
  • If you experience persistent or unexplained fatigue, muscle pain, or weakness, consult your healthcare provider to consider carnitine testing and to discuss possible L-carnitine or CoQ10 supplementation under supervision.
1 effect allele — CG genotype (carrier of one altered copy)

You carry one copy of the effect allele for rs11568520. This means you have one normal and one altered SLC22A5 gene. OCTN2 transporter function may be somewhat less efficient under certain stresses, though most carriers remain symptom-free.

Practical implications and recommendations:

  • Maintain adequate dietary protein to supply lysine and methionine: fish, poultry, eggs, dairy, legumes, and tofu are good choices.
  • Include carnitine-containing foods like red meat and dairy if they fit your dietary preferences.
  • Ensure sufficient intake of vitamin C, iron, vitamin B6, vitamin B12, and niacin to support endogenous carnitine production.
  • Regular resistance and aerobic training, sufficient sleep, stress management, and hydration help keep mitochondrial function robust.
  • If you notice unexplained fatigue, muscle cramps, or poor exercise recovery, talk with your healthcare provider about measuring plasma carnitine and discussing the potential benefits and risks of targeted supplementation.
0 effect alleles — CC genotype (no effect allele)

Your genotype contains two copies of the non-effect allele for rs11568520. This typical profile suggests normal OCTN2 transporter function for moving carnitine into cells and conserving it in the kidneys.

To maintain strong carnitine function and energy metabolism:

  • Consume balanced protein sources that supply lysine and methionine: fish, poultry, eggs, dairy, legumes, and tofu.
  • Include carnitine-rich foods such as red meat and dairy if consistent with your diet and preferences.
  • Support synthesis and mitochondrial health with adequate vitamin C, iron, B6, B12, and niacin.
  • Adopt regular aerobic and resistance exercise, aim for 7-9 hours of sleep, manage stress, and stay well hydrated.

These foundational nutrition and lifestyle strategies support steady cellular energy for your genetic background.

Summary and next steps

Variations in SLC22A5 can influence carnitine handling, but most carriers do not develop primary carnitine deficiency. Practical steps to protect energy and muscle health include adequate protein and micronutrient intake, carnitine-containing foods if appropriate, regular exercise, good sleep, hydration, and stress management. If you experience unexplained fatigue, muscle weakness, or exercise intolerance, speak with your healthcare provider about targeted testing and whether supervised supplementation might be appropriate.

Important: PlexusDx does not provide medical advice. This information is educational and describes genetic predispositions only. Always consult your healthcare provider before starting or changing supplements, medications, or treatment plans.

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 Carnitine and SLC22A5 rs11568520

How does an SLC22A5 variant affect carnitine and mitochondrial energy?

The SLC22A5 gene helps encode the OCTN2 transporter that moves carnitine from the bloodstream into cells and helps the kidneys conserve it. Variations can change how efficiently carnitine is handled, which may influence mitochondrial fatty acid oxidation and ATP production—especially during stress, illness, very low-calorie intake, or intense exercise.

What genotype patterns (CC, CG, GG for rs11568520) mean for energy and muscle health?

GG (two effect alleles) suggests reduced OCTN2 efficiency and may increase vulnerability to low energy, muscle weakness, or exercise intolerance during metabolic stress, though most carriers remain asymptomatic. CG (one effect allele) may slightly reduce transporter efficiency under certain stresses, but most people are symptom-free. CC (no effect alleles) typically indicates normal OCTN2 transporter function for cellular carnitine uptake and kidney conservation.

What should I do to support carnitine levels if I’m a carrier of an SLC22A5 effect allele?

Support carnitine function with consistent dietary protein (lysine and methionine precursors), include carnitine-containing foods like red meat and dairy if tolerated, and ensure key micronutrients for carnitine synthesis and mitochondrial health (vitamin C, iron, B6, B12, and niacin). Pair aerobic conditioning with resistance training, prioritize 7–9 hours of quality sleep, manage stress, and stay well hydrated. If you have unexplained fatigue, muscle cramps, or exercise intolerance, consider discussing targeted blood testing (plasma free/total carnitine, creatine kinase, iron studies, B12/folate, thyroid function) and potential supervised options such as L-carnitine, coenzyme Q10, or magnesium.

What tests can help me learn more about Carnitine and SLC22A5 rs11568520?

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.