BHB

β-Hydroxybutyrate (BHB) is the predominant ketone body synthesized in the liver during periods of low glucose availability, serving both as an alternative energy substrate and as a signaling molecule with diverse biological functions. BHB is produced through ketogenesis, primarily in hepatic mitochondria, and becomes elevated during fasting, caloric restriction, ketogenic diets, and exercise. PMID 32525972PMID 40583323PMID 28826372PMID 41418322PMID 41109663

Beyond its role as an energy source, BHB functions as a signaling metabolite that regulates gene expression, inflammation, and cellular stress responses through multiple mechanisms. BHB acts as an endogenous inhibitor of histone deacetylases (HDACs), thereby influencing chromatin structure and gene transcription. PMID 28826372PMID 24140022PMID 32525972 Additionally, BHB serves as a substrate for lysine β-hydroxybutyrylation (Kbhb), a post-translational modification that modulates chromatin accessibility, gene regulation, and cellular metabolism in both histone and non-histone proteins. PMID 41418322PMID 37575967 BHB also binds to the G-protein-coupled receptor GPR109A (also known as hydroxyl-carboxylic acid receptor), mediating anti-inflammatory and anti-lipolytic effects. PMID 32525972PMID 40305364

BHB is considered an exerkine—a signaling molecule released in response to exercise that exerts systemic effects. Ketone bodies are oxidized as fuel during exercise, become markedly elevated during post-exercise recovery, and the capacity to utilize ketone bodies is enhanced in exercise-trained skeletal muscle. PMID 40157803PMID 27861911 Exercise increases BHB production, and this molecule can cross the blood-brain barrier to influence neuronal function, synaptic plasticity, and neuroprotection. PMID 40583323PMID 40157803 As an exerkine, BHB mediates beneficial effects of exercise on the brain through both direct (autonomous) effects after crossing the blood-brain barrier and indirect (non-autonomous) effects on peripheral tissues. PMID 40157803

BHB's therapeutic potential extends to cardiovascular function, where it dramatically increases myocardial blood flow and cardiac output, as well as to neuroprotection in conditions such as epilepsy and dementia. PMID 32525972PMID 40583323 Its ability to modulate autophagy, reduce oxidative stress, and regulate mitochondrial function positions BHB as a key metabolic mediator linking environmental factors like diet and exercise to cellular homeostasis. PMID 40583323PMID 40305364

Cardiovascular Applications: BHB demonstrates significant cardioprotective effects in heart failure. It serves as an efficient cardiac fuel that improves myocardial blood flow and cardiac output in both control subjects and heart failure patients. PMID 32525972 The therapeutic mechanisms include enhanced mitochondrial oxidative metabolism, reduced oxidative stress, and modulation of cardiac fuel utilization. PMID 36996176 BHB also promotes vasodilation, reduces inflammation and fibrosis, and supports angiogenesis. PMID 36996176

Neurological and Cognitive Benefits: BHB crosses the blood-brain barrier to provide neuroprotection through multiple mechanisms. It enhances cognitive processes including learning and memory by modulating synaptic plasticity and neurotransmitter levels. PMID 40583323 In adults with obesity, 14 days of BHB supplementation improved cerebral blood flow by 11-12% and enhanced cognitive performance on digit-symbol substitution testing. PMID 34605026 BHB shows promise for neurodegenerative diseases like Alzheimer's and Parkinson's by supporting proteostasis, stimulating autophagy, and reducing protein aggregation. PMID 37575967 Its use in epilepsy to reduce seizure frequency is well-established, with potential applications in other neurological conditions including dementia. PMID 32525972

Metabolic and Diabetes Treatment: BHB exhibits protective effects against type 2 diabetes mellitus by regulating glucose and lipid metabolism, preserving pancreatic β-cell integrity, and improving insulin resistance. PMID 41201041 It reduces oxidative stress, controls inflammatory responses and endoplasmic reticulum stress, while regulating mitochondrial biogenesis and autophagy. PMID 41201041 Clinical studies demonstrate that regulating BHB levels can influence body weight, fasting blood glucose, insulin resistance, and memory in diabetic patients. PMID 41201041

Epigenetic and Signaling Mechanisms: Beyond its role as an energy substrate, BHB functions as a signaling molecule with epigenetic regulatory capacity. It acts as an endogenous histone deacetylase inhibitor, inducing beneficial histone modifications that enhance cellular resilience. PMID 40583323PMID 37928021 BHB also mediates lysine β-hydroxybutyrylation (Kbhb), a post-translational modification that links ketone metabolism to gene regulation, chromatin accessibility, and cellular metabolism. PMID 41418322 These epigenetic effects are crucial in diabetes, cancer, and cardiovascular disease contexts. PMID 37928021

Anti-inflammatory and Antioxidant Properties: BHB inhibits the NLRP3 inflammasome in immune cells, reducing inflammatory cytokine production. PMID 32525972PMID 27826689 It reduces oxidative stress by altering mitochondrial NAD/NADH ratios and decreasing reactive oxygen species production. PMID 27826689 These properties contribute to its therapeutic effects across multiple organ systems including neurons, muscle, liver, and cardiovascular tissues. PMID 38193855

Clinical Translation: Multiple approaches exist to elevate circulating BHB therapeutically, including ketogenic diets, exogenous ketone salts and esters, and biologically synthesized D-3HB. PMID 34415393 Recent development of ketone monoester supplements shows particular promise, allowing elevation of plasma BHB without strict dietary restriction. PMID 34605026 The molecule is generally well-tolerated and appears safe for therapeutic use. PMID 34605026