Is there another name for lactic acid?: Understanding lactate in nutrition and diet

October 17, 2025 •

4 min read

For decades, many have mistakenly blamed 'lactic acid' for muscle burn during exercise, but the question 'Is there another name for lactic acid?' points to a much more accurate term—lactate—which reveals its true, beneficial role in nutrition and metabolism. This shift in understanding corrects a long-held misconception and highlights lactate's functions as a vital cellular fuel and signaling molecule throughout the body.

Quick Summary

The term 'lactate' is the precise name for the substance involved in metabolism, not 'lactic acid' as commonly misunderstood. It serves as an essential energy fuel and signaling molecule in nutrition, exercise, and gut health, far from being a simple waste product.

Key Points

Correct Terminology: At the body's physiological pH, lactic acid instantly dissociates into its conjugate base, called lactate.
Not a Waste Product: Contrary to older beliefs, lactate is a crucial energy substrate for various tissues, including the heart, brain, and skeletal muscles.
Lactate Shuttle Theory: This metabolic concept describes how lactate is produced in some cells and transported (shuttled) to others for oxidation and energy production.
Performance Enhancement: Elite athletes are highly efficient at clearing and utilizing lactate as fuel, which contributes to their superior endurance and performance.
Debunking the Myth: The burning sensation during high-intensity exercise is caused by hydrogen ions, and lactate helps buffer this acidity, delaying fatigue; it does not cause muscle soreness.
Gut Health Benefits: Lactate from fermented foods and supplements can improve gut microbiota by increasing beneficial bacteria like Lactobacillus and Bifidobacterium and reducing pathogenic species.
Dietary Source: Fermented foods such as yogurt, kefir, and sauerkraut are natural sources of lactic acid, which contributes to flavor and health benefits.

The Naming Convention: Lactic Acid vs. Lactate

The most common 'other name' for lactic acid is lactate, but the distinction is more than just semantics—it's a critical biochemical difference. Lactic acid ($C_3H_6O_3$) is the non-ionized acid form of the molecule. In the human body, which maintains a tightly regulated neutral pH, lactic acid almost instantly dissociates into a lactate anion ($C_3H_5O_3^−$) and a hydrogen ion ($H^+$). Therefore, what circulates in the blood and is used metabolically by the body is overwhelmingly lactate, not lactic acid. This crucial clarification helps debunk the long-standing myth that 'lactic acid buildup' is solely responsible for muscle fatigue and soreness. The burning sensation during intense exercise is primarily caused by the accumulation of hydrogen ions, while lactate actually acts as a buffer to reduce acidity and delay fatigue.

Lactate: A Misunderstood Metabolic Fuel

For decades, lactate was mistakenly viewed as a metabolic waste product generated only under oxygen-deprived conditions. The 'lactate shuttle theory,' first proposed by physiologist George Brooks, has revolutionized this understanding. This theory posits that lactate is a key energy substrate that is constantly produced and consumed by tissues, even under aerobic conditions. It serves as a vital fuel source for various parts of the body, including:

The heart: Under stress or high energy demand, the heart can derive a significant portion of its energy turnover from lactate oxidation.
The brain: The brain can preferentially use lactate for energy, especially during periods of increased neural activity or when glucose is limited.
Oxidative muscle fibers: Lactate produced in one muscle fiber (typically fast-twitch) can be transported to another (slow-twitch) and used for fuel.
The liver: Via the Cori cycle, the liver can convert lactate back into glucose, which can then be released into the bloodstream for energy or stored as glycogen.

The Lactate Shuttle and Athletic Performance

Understanding the lactate shuttle is key to modern sports nutrition and training. The ability of elite athletes to sustain high-intensity exercise is directly related to their superior capacity to transport and utilize lactate for energy. This is a trainable adaptation involving improvements in the number and efficiency of monocarboxylate transporters (MCTs) and mitochondria. This differs significantly from the older, incorrect view that high lactate levels were a sign of inadequate anaerobic metabolism and impending fatigue. In reality, the more efficiently an athlete can clear and use lactate, the higher their performance ceiling becomes.

Modern Training and Lactate

Modern training methodologies, often using lactate threshold testing, are designed to optimize this metabolic flexibility. Training at specific lactate levels allows athletes to push their body's ability to clear lactate faster than it's being produced, raising their lactate threshold and improving endurance. This helps athletes manage the high metabolic demand of intense exercise more effectively.

Lactate in Your Daily Diet

Lactate is not just relevant to sports; it is also a fundamental component of many fermented foods. The production of lactic acid by lactic acid bacteria (LAB) is responsible for the characteristic flavors and preservation properties of these foods. Common dietary sources of lactate include:

Yogurt and Kefir: Dairy products fermented with LAB.
Sauerkraut and Kimchi: Fermented vegetables.
Sourdough bread: Leavened using LAB.
Pickles: Made with lactic acid fermentation.

Lactate and Gut Microbiota

Beyond fermentation, recent research shows a link between lactate and gut health. A 2024 meta-analysis revealed that lactate supplementation can significantly increase beneficial bacteria like Lactobacillus and Bifidobacterium in the gut. It also showed that lactate intake could decrease the Firmicutes-to-Bacteroidetes ratio, which is often associated with improved gut function. The effects of lactate on the gut are dose- and age-dependent, with younger adults showing more consistent benefits. Lactate can also reduce the abundance of pathogenic species, further promoting a healthier gut ecosystem.

Lactate Supplementation: Benefits and Considerations

While lactate is a natural energy source, supplements are also being investigated. As an ergogenic aid, lactate supplementation has shown potential benefits in specific, high-intensity endurance scenarios. However, studies have yielded conflicting results regarding performance enhancement, and the practical application for prolonged exercise is complicated by potential gastrointestinal side effects. In medical contexts, such as treating traumatic brain injury, lactate has been explored as a therapeutic energy substrate for the brain.


Feature	Lactic Acid	Lactate
Chemical Form	A neutral, protonated carboxylic acid ($C_3H_6O_3$).	An anion ($C_3H_5O_3^−$), the deprotonated form.
In the Body	Present only transiently before dissociating.	The predominant form present in blood and tissues at physiological pH.
Energy Role	Incorrectly linked to the negative effects of anaerobic metabolism.	A dynamic and vital cellular fuel, signaling molecule, and metabolic link.
Muscle Fatigue Myth	The mythical cause of muscle 'burn' and delayed-onset soreness.	Actually helps buffer acidity, delaying fatigue. Not responsible for soreness.

Conclusion

To definitively answer the question, is there another name for lactic acid? Yes, and the more accurate term is lactate. This shift in terminology reflects a paradigm change in nutrition science. Lactate is no longer the notorious waste product of intense effort, but a dynamic and multifaceted molecule. Its role as a vital fuel for the heart, brain, and muscles, its involvement in athletic performance, and its benefits for gut health demonstrate its importance. By understanding lactate's true function, we can appreciate its positive contributions to human metabolism and health, moving beyond outdated and misleading myths. Further research continues to uncover new signaling roles, solidifying lactate's place as a fundamental component of a healthy, active metabolism. For additional authoritative information on the subject, see this resource from the National Institutes of Health: Modern Perspective of Lactate Metabolism.

Frequently Asked Questions

The key difference is their chemical form at the body's pH. Lactic acid is the neutral, protonated molecule, but it quickly loses a hydrogen ion to become the lactate anion in the bloodstream and tissues. Therefore, lactate is the correct term for the substance involved in human metabolism.

No, this is a common myth. The buildup of hydrogen ions, not lactate, is responsible for the burning sensation during intense exercise. Lactate actually helps buffer this acidity. Delayed onset muscle soreness (DOMS) felt days after a workout is caused by microtrauma to muscle fibers, not lactate accumulation.

Lactate is an important metabolic fuel that can be used by the heart, brain, and oxidative muscle fibers to generate energy. The lactate shuttle allows for efficient redistribution of this fuel, helping to sustain performance during high-intensity and endurance activities.

Lactate is present in many fermented foods, such as yogurt, kefir, sauerkraut, kimchi, and sourdough bread. The lactic acid bacteria used in fermentation produce it, contributing to both the food's flavor and its preservation.

Yes, research indicates that the brain can and does use lactate for fuel, especially during heightened brain activity or conditions where glucose availability is altered. Lactate can be transported from the bloodstream into the brain to meet its energy demands.

Lactate is fundamentally beneficial for the body. It is a vital energy fuel and signaling molecule involved in maintaining metabolic homeostasis. Only in rare pathological conditions, such as severe lactic acidosis, does high lactate become a sign of a serious underlying issue, but it is not harmful in itself.

Lactate can have a beneficial impact on gut health. A recent meta-analysis showed that lactate supplementation increases the abundance of beneficial bacteria like Lactobacillus and Bifidobacterium. It can also help regulate the ratio of Firmicutes to Bacteroidetes and reduce the presence of pathogenic species.