NMN for Endurance Athletes: The Aerobic Capacity Evidence

NMN for Endurance Athletes is a topic that sits at the intersection of cellular metabolism and real-world performance. Endurance sports place extraordinary demands on mitochondrial function, and nicotinamide mononucleotide (NMN) has emerged as a compound that may support the very energy systems athletes rely on. But the critical question isn't whether NMN works in a petri dish—it's whether the human evidence justifies its use for cyclists, runners, and triathletes looking for a legitimate edge.

What the Human Studies Actually Show

The research landscape on NMN and endurance performance is still young, but one study stands out as directly relevant. Liao et al. (2021) conducted a randomized, double-blind, placebo-controlled trial specifically in amateur runners—a population that mirrors the weekend warrior and competitive amateur athlete. Forty-eight healthy participants were assigned to one of four groups: placebo, or NMN at 300 mg, 600 mg, or 1200 mg daily for six weeks. All groups followed an identical training protocol.

The results showed a dose-dependent improvement in aerobic capacity, measured by VO₂max and time to exhaustion. The 600 mg and 1200 mg groups saw the largest gains, with the high-dose group showing approximately 10% improvement in VO₂max compared to baseline. Notably, the 300 mg group showed modest but statistically significant improvements as well. This suggests that even lower doses can move the needle when paired with structured training.

Other human trials provide supporting evidence for NMN's physiological effects, though not in athletic populations. Yoshino et al. (2021) demonstrated that NMN increased muscle insulin sensitivity in prediabetic women, a finding relevant to metabolic efficiency during prolonged exercise. Igarashi et al. (2022) showed that 250 mg of NMN daily for 12 weeks improved muscle function and increased blood NAD⁺ levels in healthy older men. Irie et al. (2020) confirmed that oral NMN is well-absorbed and raises NAD⁺ metabolites in healthy Japanese men at doses of 100–500 mg.

Niu et al. (2023) added another layer, finding that short-term NMN supplementation altered serum metabolism and was associated with changes in telomere length in a pre-aging cohort. While not an athletic study, it reinforces the idea that NMN engages fundamental cellular repair pathways that could support recovery from training stress.

Study	Population	Dose & Duration	Key Outcome	Relevance to Endurance
Liao et al. (2021)	48 amateur runners	300–1200 mg/day, 6 weeks	↑ VO₂max, ↑ time to exhaustion (dose-dependent)	Direct: trained athletes, performance measured
Yoshino et al. (2021)	25 prediabetic women	250 mg/day, 10 weeks	↑ Muscle insulin sensitivity	Indirect: metabolic efficiency
Igarashi et al. (2022)	42 healthy older men	250 mg/day, 12 weeks	↑ NAD⁺, improved muscle function	Indirect: muscle function, aging athletes
Irie et al. (2020)	10 healthy men	100–500 mg/day, single and repeated doses	↑ NAD⁺ metabolites, well-tolerated	Indirect: bioavailability confirmed
Niu et al. (2023)	36 pre-aging adults	300 mg/day, 8 weeks	Altered serum metabolism, telomere length changes	Indirect: recovery, cellular repair

The table above makes one thing clear: only Liao et al. (2021) directly tested endurance outcomes. The other studies build a plausible biological case but do not demonstrate performance enhancement in trained individuals. This distinction matters. An athlete considering what NMN is and how it works should understand that the performance evidence, while promising, rests primarily on a single RCT.

How NMN Supports Aerobic Metabolism

To understand why NMN might help endurance athletes, you need to understand NAD⁺. Nicotinamide adenine dinucleotide is a coenzyme found in every cell, essential for mitochondrial ATP production. Without adequate NAD⁺, the electron transport chain—the core engine of aerobic respiration—cannot function efficiently. During prolonged exercise, muscle cells consume enormous amounts of ATP, and NAD⁺ is consumed in the process.

Here's where it gets interesting: NAD⁺ levels decline with age, but they also fluctuate with metabolic stress. Gomes et al. (2013) demonstrated that declining NAD⁺ disrupts nuclear-mitochondrial communication, creating what they termed a "pseudohypoxic state." In this state, cells behave as if oxygen is scarce even when it is not, downregulating oxidative metabolism. For an endurance athlete, this is precisely the wrong metabolic signal. Restoring NAD⁺ levels could theoretically restore normal nuclear-mitochondrial signaling, allowing muscles to utilize oxygen more efficiently.

NMN is a direct precursor to NAD⁺. When taken orally, it is absorbed and converted to NAD⁺ in tissues, including skeletal muscle. Igarashi et al. (2022) confirmed that chronic NMN supplementation elevates blood NAD⁺ levels and alters muscle function biomarkers in humans. The mechanism is not speculative: NMN → NAD⁺ → enhanced oxidative phosphorylation capacity. Whether this translates to measurable performance gains depends on whether the athlete was NAD⁺-limited to begin with.

Dosing: What the Evidence Suggests

The Liao et al. (2021) study provides the most useful dosing framework for athletes. The dose-response curve was clear: 300 mg produced modest gains, 600 mg produced stronger gains, and 1200 mg produced the largest improvements in VO₂max. No serious adverse events were reported at any dose, and NMN was well-tolerated across the board.

However, more is not always better. Igarashi et al. (2022) used only 250 mg daily and still saw meaningful changes in muscle function and NAD⁺ levels in older men. Irie et al. (2020) found that 100–500 mg effectively raised NAD⁺ metabolites. This suggests that individual needs may vary based on age, baseline NAD⁺ status, and training volume. Younger athletes with higher baseline NAD⁺ may require less supplementation to see effects, while older or heavily training athletes may benefit from higher doses.

For athletes considering a specific product, Bio:sudo NMN 1000mg provides a dose that falls within the studied range, near the upper end where the strongest performance effects were observed. It is worth noting that the 1200 mg dose in Liao et al. (2021) was the highest tested in an athletic population, and 1000 mg is reasonably close to that benchmark. That said, athletes should consider starting lower and assessing tolerance, as individual responses to NAD⁺ precursors vary. You can learn more about dosing nuances in our NMN dosage guide.

What the Evidence Does Not Show

It is equally important to be clear about what has not been demonstrated. No study has shown that NMN improves performance in elite athletes. Liao et al. (2021) used amateur runners, and the baseline VO₂max values suggest a recreationally trained population, not professionals. Whether elite athletes—who already optimize every variable—would see additional gains is unknown.

There is also no direct evidence that NMN improves lactate threshold, sprint performance, or strength. The mechanism is fundamentally aerobic, and any benefits are likely limited to sustained submaximal efforts. A sprinter or powerlifter should not expect NMN to improve their primary performance metric based on current data.

Additionally, no long-term safety data in athletes extends beyond 12 weeks. The studies cited are short-to-medium in duration, and the effects of years of continuous NMN supplementation are unknown. NAD⁺ metabolism is complex, and chronic elevation could theoretically have downsides that have not yet been identified.

For a broader view of what NMN has been shown to do—and what remains unproven—see our breakdown of NMN benefits with actual human evidence.

Who Benefits Most

The evidence suggests three populations where NMN supplementation is most justified:

Aging amateur endurance athletes. Igarashi et al. (2022) and Niu et al. (2023) both studied older adults and found that NMN improved muscle function and metabolic markers. For the masters athlete—typically 40 years or older—declining NAD⁺ may be a genuine limiter. Restoring NAD⁺ via NMN could offset age-related metabolic inefficiency.

Recreationally competitive athletes seeking marginal gains. The Liao et al. (2021) population fits this profile. These are individuals who train consistently, race occasionally, and have already optimized training, nutrition, and recovery. For them, a 5–10% improvement in VO₂max from a well-tolerated supplement is meaningful.

Athletes in heavy training blocks. While not directly studied, the metabolic stress of high-volume training may deplete NAD⁺ faster than it can be regenerated. NMN supplementation during intensified training periods—such as marathon build-ups or cycling camp blocks—could theoretically support mitochondrial recovery between sessions. This is speculative but grounded in the biochemistry of NAD⁺ turnover.

Practical Takeaways

• The only direct performance study in athletes is Liao et al. (2021), which found dose-dependent improvements in VO₂max at 300–1200 mg/day over six weeks.
• NMN works by elevating NAD⁺, a coenzyme required for mitochondrial ATP production and efficient oxygen utilization.
• Older and recreationally trained athletes are the most likely to benefit; elite athletes have not been studied.
• Doses of 250–1200 mg have been used safely in human trials. A product like Bio:sudo NMN 1000mg aligns with the higher end of the studied range.
• NMN is not a substitute for training. It showed benefits only when combined with a structured running protocol.
• Long-term safety data beyond 12 weeks is not available. Cyclical use or periodic breaks may be prudent.

Bottom Line

NMN for endurance athletes has a plausible mechanism and one promising RCT showing improved aerobic capacity in amateur runners. The evidence is not overwhelming, but it is more solid than many supplements marketed to athletes. If you are a masters runner, cyclist, or triathlete already training smart and eating well, NMN is a reasonable experiment—with realistic expectations. It is not a magic pill, but it may be a genuine metabolic tool.

References

1. Yoshino M, et al. "Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women." Science. 2021;372(6547):1224–1229. [Source]
2. Igarashi M, et al. "Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men." npj Aging. 2022;8(1):5. [Source]
3. Irie J, et al. "Effect of oral administration of nicotinamide mononucleotide on clinical parameters and nicotinamide metabolite levels in healthy Japanese men." Endocrine Journal. 2020;67(2):153–160. [Source]
4. Liao B, et al. "Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners: a randomized, double-blind study." Journal of the International Society of Sports Nutrition. 2021;18(1):54. [Source]
5. Gomes AP, et al. "Declining NAD+ induces a pseudohypoxic state disrupting nuclear-mitochondrial communication during aging." Cell. 2013;155(7):1624–1638. [Source]
6. Niu KM, et al. "The impacts of short-term NMN supplementation on serum metabolism, fecal microbiota, and telomere length in pre-aging phase." Nutrients. 2023;15(3):755. [Source]

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