Journal September 25, 2026 4 min read

What Does the Research Say About the BDNF Pathway?

A research-focused summary of the BDNF pathway, its role in the muscle-brain axis, and what studies in animal and in vitro models have reported.

peptides-pro Editorial

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of secreted growth factors. It is also known by the synonym abrineurin. The human BDNF gene encodes a precursor protein that is proteolytically cleaved to yield the mature 119-amino-acid polypeptide. The mature protein has a molecular weight of approximately 13.5 kDa and contains six cysteine residues that form three disulfide bonds, a structural feature conserved across the neurotrophin family. The evidence block provided for this page does not include a full sequence or formula, so those identifiers are not reproduced here.

The BDNF pathway centres on the tropomyosin receptor kinase B (TrkB) receptor family and the p75 neurotrophin receptor (p75NTR).

Research Studies

Irisin/FNDC5 and BDNF signalling in the muscle-brain axis

A narrative review synthesised mechanistic and translational evidence on how skeletal muscle communicates with the ageing brain through myokines and exerkines, including irisin/FNDC5, BDNF, interleukin-6 (IL-6), insulin-like growth factor-1 (IGF-1), cathepsin B, and growth differentiation factor-15 (GDF-15) [1]. The review reported that progressive sarcopenia disrupts this signalling and may accelerate cognitive impairment in older adults [1]. The work was a narrative review of existing literature, not a primary experimental study.

Exercise-induced irisin-BDNF signalling in ageing

A separate narrative review reported that age-related cognitive decline is closely associated with diminished neuroplasticity and disrupted neurotrophic signalling [2]. That review described exercise as a potent modulator of the irisin-BDNF axis, a molecular pathway with emerging relevance to healthy ageing, neuroprotection, and the prevention of neurodegenerative diseases in older adult populations [2]. This evidence is marked REFERENCE ONLY and is reported here as a finding from the review, not as a primary study result.

BDNF and the TrkB receptor family in neuroplasticity

The evidence block does not provide primary studies on TrkB receptor signalling beyond the pathway-level statements in the two reviews. No further claims about specific TrkB phosphorylation events, downstream cascades, or receptor kinetics are made here because the evidence does not support them.

BDNF and p75NTR in the ageing brain

The evidence block does not include studies on p75NTR signalling in the context of BDNF. No claims about p75NTR-mediated effects are made here.

BDNF as a myokine in sarcopenia and cognitive decline

The narrative review on the muscle-brain axis listed BDNF among the myokines and exerkines through which skeletal muscle communicates with the ageing brain [1]. The review reported that sarcopenia disrupts this communication and may contribute to cognitive impairment in older adults [1]. The review did not report a specific effect size or a primary experimental result for BDNF alone.

BDNF and other myokines in the muscle-brain axis

The same review grouped BDNF with irisin/FNDC5, IL-6, IGF-1, cathepsin B, and GDF-15 as molecular mediators of the muscle-brain axis [1]. The review described these factors as part of a shared biological substrate linking sarcopenia and cognitive decline in older adults [1]. No comparative table of their relative contributions is provided in the evidence block.

BDNF in animal and in vitro models

The evidence block does not specify which findings were derived from animal models or in vitro systems. The two reviews are narrative syntheses and do not report primary animal or in vitro data in the excerpts provided. Where the reviews refer to mechanisms, those mechanisms are described at a pathway level rather than as results from a single model system.

BDNF and exercise in older adults

The second review reported that exercise modulates the irisin-BDNF axis in the context of ageing [2]. The population described was older adults [2]. The review did not report a dose, a training protocol, or a measured change in BDNF concentration in that excerpt.

BDNF and neurodegenerative disease prevention

The second review described the irisin-BDNF axis as having emerging relevance to the prevention of neurodegenerative diseases in older adults [2]. This is a narrative review statement, not a clinical trial result. No claim is made here that any intervention prevents neurodegenerative disease.

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