Relaxin and INSL3: Two Peptide Hormones That May Protect Your Bones and Muscles
Relaxin and insulin-like peptide 3 (INSL3) — hormones known for roles in pregnancy and male reproduction — also regulate bone remodeling and muscle regeneration, potentially offering new approaches to osteoporosis and sarcopenia.
Quick Facts
What This Study Found
Relaxin and insulin-like peptide 3 (INSL3) — two peptide hormones traditionally associated with pregnancy and testicular function — appear to play important roles in bone and muscle health. Relaxin is involved in bone remodeling (balancing bone formation and breakdown), helps heal injured ligaments, and promotes skeletal muscle regeneration. INSL3, a male-specific hormone from testicular Leydig cells, also participates in bone remodeling.
Both peptides may help explain sex differences in osteoporosis and sarcopenia risk, and could represent new therapeutic targets for musculoskeletal diseases.
Key Numbers
Review article — no primary experimental data presented
How They Did This
This is a narrative review synthesizing published preclinical and clinical evidence on relaxin and INSL3 in the musculoskeletal system. The authors examined cell culture studies, animal models, and available clinical data to build a case for these peptides' roles in bone remodeling, ligament healing, and muscle regeneration.
Why This Research Matters
Osteoporosis and sarcopenia (age-related muscle loss) affect hundreds of millions of people worldwide. Current treatments are limited. If relaxin and INSL3 genuinely influence bone and muscle health, they could open entirely new therapeutic avenues — particularly for age-related musculoskeletal decline and for understanding why men and women experience these conditions differently.
The Bigger Picture
The musculoskeletal system is regulated by a complex network of hormones, and we're still discovering new players. Relaxin has already attracted attention for cardiovascular and fibrosis applications — if its bone and muscle effects are confirmed clinically, it could become a multi-indication peptide therapeutic. INSL3's role adds to our understanding of why men and women age differently in terms of bone and muscle mass.
What This Study Doesn't Tell Us
As a narrative review, this does not present new experimental data. Much of the evidence comes from animal models and cell studies — clinical evidence in humans is still limited. The review is part of a themed journal section on relaxin family peptides, which may introduce selection bias toward positive findings. No systematic search methodology is described.
Questions This Raises
- ?Could relaxin-based therapies prevent or reverse age-related bone loss and muscle wasting in humans?
- ?Does declining INSL3 in aging men contribute to their increasing osteoporosis and sarcopenia risk?
- ?How do relaxin and INSL3 interact with established musculoskeletal regulators like estrogen and testosterone?
Trust & Context
- Key Stat:
- Dual musculoskeletal roles discovered Relaxin promotes bone remodeling, ligament healing, and muscle regeneration — functions far beyond its known role as a pregnancy hormone
- Evidence Grade:
- This is a narrative review that synthesizes mostly preclinical evidence (animal and cell studies). While published in a high-quality pharmacology journal, it presents no new data and the clinical evidence for musculoskeletal applications remains limited.
- Study Age:
- Published in 2017. The relaxin field has continued to advance since this review. Some of the therapeutic hypotheses discussed may have been further tested in the intervening years. The foundational biology described remains relevant.
- Original Title:
- Relaxin and insulin-like peptide 3 in the musculoskeletal system: from bench to bedside.
- Published In:
- British journal of pharmacology, 174(10), 1015-1024 (2017)
- Authors:
- Ferlin, Alberto, De Toni, Luca, Sandri, Marco, Foresta, Carlo
- Database ID:
- RPEP-03283
Evidence Hierarchy
Frequently Asked Questions
What is relaxin and what does it normally do?
Relaxin is a peptide hormone best known for its role in pregnancy — it loosens ligaments and softens the cervix to prepare for childbirth. It's also produced by the prostate gland in men. This review highlights its additional roles in bone remodeling, ligament repair, and skeletal muscle regeneration.
Could relaxin or INSL3 be used to treat osteoporosis?
Potentially, but it's too early to say. Animal and cell studies suggest both peptides influence how bone is formed and broken down. Human clinical trials for musculoskeletal applications haven't been conducted yet, so this remains a promising research direction rather than an available therapy.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-03283APA
Ferlin, Alberto; De Toni, Luca; Sandri, Marco; Foresta, Carlo. (2017). Relaxin and insulin-like peptide 3 in the musculoskeletal system: from bench to bedside.. British journal of pharmacology, 174(10), 1015-1024. https://doi.org/10.1111/bph.13490
MLA
Ferlin, Alberto, et al. "Relaxin and insulin-like peptide 3 in the musculoskeletal system: from bench to bedside.." British journal of pharmacology, 2017. https://doi.org/10.1111/bph.13490
RethinkPeptides
RethinkPeptides Research Database. "Relaxin and insulin-like peptide 3 in the musculoskeletal sy..." RPEP-03283. Retrieved from https://rethinkpeptides.com/research/ferlin-2017-relaxin-and-insulinlike-peptide
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.