What is Anserine and Where Does it Come From?
Anserine ($eta$-alanyl-1-methyl-L-histidine) is a naturally occurring dipeptide, a small protein fragment composed of two amino acids. It is a methylated analog of carnosine and is highly concentrated in the skeletal muscles of certain animals, notably migratory birds and fish, such as bonito tuna. For this reason, chicken and fish extracts are common sources for anserine supplements. In the human body, anserine and carnosine act as powerful intracellular buffers, helping to manage the buildup of hydrogen ions ($H^+$) that occurs during intense exercise. This buffering capacity is one of the key mechanisms believed to contribute to its ergogenic, or performance-enhancing, effects.
Anserine vs. Carnosine: A Key Difference
A major difference between anserine and its more widely known counterpart, carnosine, is its resistance to an enzyme called carnosinase. While carnosine is rapidly broken down by this enzyme in the bloodstream, anserine is more stable and remains in the plasma longer. This superior bioavailability means that anserine can maintain its buffering and antioxidant activity more effectively after ingestion, which is why supplements often contain both compounds to maximize their combined effect. The differing pKa values also suggest they may buffer at different points of exercise-induced acidosis.
Mechanisms of Performance Enhancement
Anserine's potential to improve athletic performance stems from two primary physiological mechanisms: buffering capacity and antioxidant activity. These roles are critical for mitigating the effects of intense physical exertion.
Intracellular Buffering
During high-intensity exercise, muscles produce a significant amount of lactic acid, which disassociates into lactate and hydrogen ions ($H^+$). The accumulation of $H^+$ lowers muscle pH, leading to muscle acidosis and a burning sensation that contributes to fatigue. Anserine, along with carnosine, helps to buffer these hydrogen ions, delaying muscle fatigue and allowing for a longer duration of high-intensity effort. Studies on cycling sprints show that combined anserine and carnosine supplementation can improve peak power and maximal muscle contractions.
Antioxidant Activity
Intense exercise increases the production of reactive oxygen species (ROS), which cause oxidative stress and cellular damage. Anserine exhibits potent antioxidant properties that help to neutralize these free radicals, thereby protecting muscle cells from damage. By reducing oxidative stress, anserine supports cellular homeostasis and may contribute to a faster recovery process after strenuous activity. Some studies have shown that anserine supplementation increases the body's antioxidant enzyme activity, such as superoxide dismutase (SOD), in response to exercise.
Potential Anti-Fatigue Effects
Research on anserine's anti-fatigue effects has shown promising results. An electromyogram (EMG) study revealed that anserine supplementation helped mitigate muscle fatigue during an intense isometric exercise test. The findings suggest that the compound supports muscle function during and after strenuous exercise. Another study in middle-distance runners found that after one week of supplementation, runners in the anserine group completed time trials faster and showed reduced creatine phosphokinase (CPK) activity, a marker of muscle damage.
How Anserine Can Help Specific Types of Exercise
The effects of anserine vary depending on the type of physical activity. Evidence points to different benefits for high-intensity and endurance-based exercises.
For High-Intensity and Power Athletes
- Repeated Sprints: Studies on high-intensity cycling protocols have shown that acute supplementation with a combination of anserine and carnosine can significantly improve performance during repeated cycling sprints. This is likely due to the enhanced buffering capacity helping to sustain peak power output over multiple efforts.
- Maximal Contractions: In addition to sprint performance, some research indicates improved maximal voluntary isometric contractions following acute combined supplementation.
For Endurance Athletes
- Reduced Fatigue: Combined anserine and carnosine supplementation has been shown to reduce blood lactate concentration and perceived fatigue during high-intensity endurance exercises. This could help endurance athletes push harder for longer periods, particularly in the final stages of a race.
- Enhanced Antioxidant Response: By boosting antioxidant activity, anserine can help protect against exercise-induced cellular damage during prolonged endurance activities, supporting better overall recovery.
Comparison: Anserine vs. Carnosine
| Feature | Anserine | Carnosine | Key Implications for Athletes |
|---|---|---|---|
| Molecular Structure | Methylated analog of carnosine. | Non-methylated dipeptide. | Anserine's methylation provides better stability. |
| Bioavailability | High resistance to the carnosinase enzyme. | Rapidly degraded by carnosinase in human plasma. | Anserine remains active longer in the bloodstream after oral intake. |
| Buffering Capacity | High proton sequestering capacity, potentially better for early stages of acidosis due to different pKa. | High proton sequestering capacity, potentially better for later stages of exercise with lower pH. | Combining both offers comprehensive buffering throughout exercise intensity levels. |
| Natural Source | Abundant in migratory animal muscles like chicken, salmon, and bonito tuna. | Found in mammalian skeletal muscle, like beef and pork. | Dietary sources differ, with fish and poultry rich in anserine. |
| Optimal Strategy | May show effects when taken acutely before exercise due to rapid bioavailability. | Often taken over time (e.g., via Beta-Alanine) to increase muscle stores. | Anserine is a candidate for an acute pre-workout boost. |
Considerations and Future Research
While studies present promising data, some results are mixed, and more research is needed to solidify the claims. For example, one trial found no significant effect of anserine on overall time to exhaustion during a specific running test, despite observing positive antioxidant and cellular integrity markers. Differences in study design, supplementation protocols, exercise protocols, and individual carnosinase activity levels may all influence outcomes. For this reason, athletes should consider existing research and consult with a sports nutrition professional before adding anserine supplements to their routine.
Important areas for further study include:
- Investigating the specific ergogenic mechanisms more closely.
- Determining optimal timing and protocols for different sports and activities.
- Comparing the effects of pure anserine versus mixed anserine/carnosine supplements.
- Evaluating long-term supplementation effects on various athletic populations.
For additional scientific context on anserine and other imidazole dipeptides, see this comprehensive review from MDPI: Anserine, Balenine, and Ergothioneine: Impact of Histidine-Containing Dipeptides on Exercise Performance and Recovery.
Conclusion
Anserine demonstrates potential as an effective athletic supplement, primarily through its roles as an intracellular buffer and potent antioxidant. Research supports its ability to help reduce muscle fatigue and enhance power output, especially during high-intensity, short-duration exercises and sprints. The compound's high bioavailability compared to carnosine makes it a strong candidate for acute pre-exercise supplementation. While the evidence is encouraging, more conclusive, long-term studies are needed to fully understand its ergogenic potential and best applications. Athletes considering anserine should be aware of its potential benefits for buffering acid, reducing oxidative stress, and aiding recovery, while also acknowledging that research is still evolving.
Disclaimer: This information is for general knowledge and should not be taken as medical advice. Consult with a healthcare professional before starting any new supplement regimen.
