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.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on blood testing & biomarkers. Browse all Blood Testing & Biomarkers education

Lactate has an image problem. For decades it was blamed for muscle burn and treated as metabolic waste. The science says otherwise: lactate is a fuel, a signal, and a link between how your muscles handle sugar and how they produce energy. Genetics shapes how efficiently you make, move, and clear it — with variants in genes like SLC16A1 and PPARGC1A influencing your metabolic response to exercise.

What lactate actually is

When your body breaks down glucose for energy through glycolysis, it produces pyruvate. When energy demand outpaces the oxygen-dependent pathways in your mitochondria, pyruvate is converted to lactate. Far from being useless, that lactate can be shuttled to other cells and tissues and burned for fuel, or sent to the liver and rebuilt into glucose. It is a recyclable energy currency, not a dead end.

Lactate, exercise intensity, and the lactate threshold

As exercise intensity rises, lactate production climbs. At lower intensities your body clears it as fast as you make it. Past a certain point — the lactate threshold — production outstrips clearance and blood lactate rises sharply. That threshold is a well-established marker of endurance fitness: better-trained individuals sustain higher intensities before lactate accumulates. The old idea that lactate directly causes muscle soreness has largely been overturned.

Lactate and sugar metabolism

Lactate ties directly to how your body handles sugar. Through the Cori cycle, lactate produced in working muscle travels to the liver and is converted back into glucose, which returns to the muscle as fuel. This loop links glycolysis, blood sugar, and energy production. Efficient lactate handling supports stable energy during exercise; disrupted handling can affect both performance and glucose dynamics.

SLC16A1: the gene that moves lactate

SLC16A1 codes for MCT1, a monocarboxylate transporter that shuttles lactate across cell membranes — out of cells that produce it and into cells that use it. Variants in SLC16A1 have been studied in the context of lactate transport and exercise response, with some associated with differences in how quickly lactate is cleared. Because MCT1 is central to the lactate shuttle, this gene is a natural focal point for exercise metabolism.

PPARGC1A, ACTN3, and mitochondrial capacity

PPARGC1A codes for PGC-1 alpha, a master regulator of mitochondrial production. More mitochondrial capacity generally means better lactate clearance and aerobic energy production. ACTN3, the well-known sprint versus endurance gene, influences muscle fiber composition, which in turn affects how much lactate you generate at a given intensity. Together these variants help explain why people respond so differently to the same training.

The Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights across peptide-related biological pathways, including systems tied to energy metabolism and exercise physiology. It offers educational, pathway-level context about your biology — not a performance prescription and not a diagnosis of any condition.

What to do with the information

Understanding your lactate and energy-metabolism genetics can inform, not dictate, how you train. People with strong aerobic-capacity tendencies may respond well to volume; others may benefit from targeted threshold work. The practical levers are the same evidence-based ones: progressive training, adequate recovery, and nutrition that supports your goals. Genetics helps you personalize the approach and set realistic expectations.

Want to understand the genetic systems behind your energy metabolism and exercise response? The Precision Peptide Genetic Test analyzes your DNA across peptide-related pathways so you can train with better information. Test before you invest in any protocol.

Frequently Asked Questions

Does lactate cause muscle soreness?

No. This is a persistent myth. Lactate is cleared within about an hour of exercise, while delayed-onset muscle soreness peaks a day or two later and is linked to microscopic muscle damage and inflammation. Lactate is better understood as a fuel and a signal, not the cause of post-workout soreness.

How does lactate relate to sugar metabolism?

Lactate is produced when glucose is broken down for energy faster than mitochondria can fully process it. Through the Cori cycle, the liver converts lactate back into glucose, which returns to muscle as fuel. This loop tightly links lactate handling, blood sugar, and energy production during exercise.

What is the SLC16A1 gene?

SLC16A1 codes for MCT1, a transporter that moves lactate across cell membranes — exporting it from producing cells and importing it into cells that use it for fuel. Variants can influence lactate transport and clearance, making SLC16A1 a key gene in exercise and energy metabolism research.

Can genetics improve my athletic performance?

Genetics influences tendencies — mitochondrial capacity, muscle fiber type, lactate handling — but it does not determine performance. Training, recovery, and nutrition drive most improvement. Genetic insight helps you understand your starting point and personalize your approach; it is not a shortcut and not a guarantee of any athletic outcome.

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use, and it does not diagnose, treat, cure, manage, or prevent any medical condition. Consult a qualified healthcare provider before making decisions about your health.

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.

This article is part of the PlexusDx Education Hub. Browse all Blood Testing & Biomarkers education