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Niacin ingestion during exercise suppresses fatty acid availability and increases carbohydrate oxidation, but does not detectably influence post-exercise energy intake.

In a crossover study of 15 healthy participants (5 female), niacin ingestion during cycling suppressed plasma NEFA concentrations and total fat oxidation (mean difference vs fasted: -9±5 g, p=0.001), similar to carbohydrate ingestion. Niacin increased plasma GLP-1 total concentrations compared to fasting, but ad libitum energy intake two hours post-exercise did not differ between conditions (FAST 833±206 kcal, CARB 786±219 kcal, NIACIN 780±158 kcal, p=0.37).

Last updated: Aug 12, 2026•1 RCTs•📖 Read as article →

Evidence Score

Evidence Score44/100
Human RCT★★☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Metabolic, endocrine and appetite responses to carbohydrate versus niacin ingestion during exercise in healthy females and males.

observational

Bradshaw L, Moreno-Cabañas A, Spellanzon B, Hutchins K, Narang B, Collins AJ, Koumanov F, Betts JA, Gonzalez JT · The Journal of nutrition (2026)

Participants: N/A
Duration: Crossover design, each condition on separate days (duration not specified)
Intervention: Niacin ingestion during 1 hour of cycling at 95% lactate threshold (compared to carbohydrate ingestion and fasting)
Outcome: Post-exercise plasma NEFA, fat oxidation, GLP-1, ketone bodies, VLDL-TG, BCAA concentrations, and ad libitum energy intake
Effect Size: N/A (no effect size reported for primary outcome; mean difference for fat oxidation: -9±5 g)
Population: Healthy females and males (n=15, 5 female)

Result:

PubMed: 42567359DOI: 10.1016/j.tjnut.2026.101773

Mechanism Graph

Niacin suppresses lipolysis in adipose tissue via insulin-independent pathway
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Reduced plasma NEFA availability decreases fatty acid oxidation during exercise
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Increased reliance on carbohydrate oxidation during exercise
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Elevated GLP-1 concentrations post-exercise
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No significant change in ad libitum energy intake

Limitations

  • ⚠Small sample size (n=15) with only 5 females, limiting generalizability
  • ⚠Energy intake measured at a single ad libitum meal, not over 24 hours
  • ⚠No blinding reported for niacin vs carbohydrate ingestion
  • ⚠Niacin dose not specified in abstract

Frequently Asked Questions

Does niacin ingestion during exercise affect appetite or food intake?▼

No significant difference in ad libitum energy intake was observed between niacin, carbohydrate, and fasting conditions (p=0.37).

How does niacin affect fat metabolism during exercise?▼

Niacin suppresses lipolysis, reducing plasma NEFA concentrations and total fat oxidation during exercise, similar to carbohydrate ingestion.

Does niacin increase GLP-1 levels?▼

Yes, niacin increased plasma GLP-1 total concentrations compared to fasting, though carbohydrate ingestion produced the highest levels.

What is the clinical significance of these findings?▼

Manipulating fatty acid availability during exercise may have greater implications for metabolic regulation than for energy balance behaviors, but more research is needed.

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References

  1. 1.Bradshaw L, Moreno-Cabañas A, Spellanzon B, Hutchins K, Narang B, Collins AJ, Koumanov F, Betts JA, Gonzalez JT. "Metabolic, endocrine and appetite responses to carbohydrate versus niacin ingestion during exercise in healthy females and males.." The Journal of nutrition, 2026. PMID: 42567359 DOI: 10.1016/j.tjnut.2026.101773
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.