When it comes to maintaining optimal muscle health, dietary protein and resistance training remain the gold standard. However, emerging clinical research suggests that bioactive peptides can offer additional layers of targeted support. PeptiStrong™ is a novel combination of three patented, highly absorbable plant-based bioactive peptides derived from the fava bean (Vicia faba). These bioactive peptides have been shown in vitro to act on certain pathways in the body that stimulate muscle protein synthesis, including mTOR and phosphorylated S6 pathways.
Previous clinical studies in men have shown that PeptiStrong™ helps to promote muscular recovery, performance, and endurance, along with supporting periods of remobilization. However, this raises an important question for practitioners: can these peptides meaningfully enhance training outcomes in both men and women? A new 2025 randomized clinical trial begins to provide some insights.
New 2025 Clinical Trial on PeptiStrong™ in Both Men and Women
A 2025 randomized, double-blind, placebo-controlled study evaluated PeptiStrong™, which the researchers refer to as a Vicia faba protein hydrolysate (VFH; 2.4 g/day), combined with resistance training in 72 healthy, untrained male and female adults in a 1:1 ratio by gender (aged 19 to 40). All participants completed three full-body resistance training sessions per week for eight weeks while maintaining consistent dietary protein intake (~1.2 g/kg/day), which did not differ significantly between groups. Outcomes were analyzed in the per-protocol population (n = 55), after excluding participants for noncompliance.
Strength Outcomes
Lower body strength improved significantly in the VFH group. By day 28, bilateral leg extension 1RM averaged 78.5 kg for VFH versus 69.0 kg for placebo (p = 0.045); by day 56, it reached 83.9 kg versus 74.7 kg (p = 0.05), reflecting a 12.2% greater strength gain in the VFH group. Although both groups improved with training, integrated area under the curve (iAUC) analysis revealed a ~24.5% greater cumulative improvement in leg strength with VFH supplementation (p = 0.140). Upper body strength gains were similar across groups, which may reflect biomechanical differences and greater hypertrophic potential in lower limb musculature.
Muscular Endurance Outcomes
Muscular endurance also improved more substantially within the VFH group. By day 56, participants in the VFH group completed 4.5 additional leg extension repetitions to failure at 80% of their 1RM, compared to 2.3 reps in the placebo group — an adjusted difference of 2.2 repetitions (p = 0.022), reflecting a 21.6% greater improvement. At the end of the study, 87% of VFH users showed enhanced leg endurance, versus 69% of those receiving a placebo.
Muscular and Metabolic Adaptions
Biomarker analyses revealed that VFH modulated several circulating myokines associated with muscular and metabolic adaptation. Plasma levels of IL-6, which supports satellite cell activation and lipid metabolism, were significantly increased, alongside markers such as FSTL-1 (linked to lipolysis), apelin (involved in muscle atrophy modulation), FABP3 (reflecting mitochondrial function), osteocrin (indicative of bone formation), and oncostatin M (associated with muscle and bone maintenance). Notably, GDF-15, a stress-related myokine tied to mitochondrial dysfunction and sarcopenia, was significantly reduced. These molecular shifts may help explain the observed gains in muscle strength, endurance, and recovery capacity.
Exploratory Bone Health Findings
Beyond muscle, exploratory DXA analysis revealed a small but statistically significant increase in whole-body bone mineral content in the VFH group (+22.2 g versus –8.2 g; p = 0.032). Although preliminary, this suggests possible benefits that extend beyond muscle adaptation and open the door for broader applications in supporting long-term musculoskeletal health.
Self-Reported Quality of Life Outcomes
Finally, self-reported health status, assessed through the RAND SF-36 questionnaire, improved significantly in the VFH group. By day 28, 51.8% of VFH users scored above 95, compared to just 14.3% in the placebo group (p = 0.008), indicating a markedly better perceived change in health.
Conclusion
Taken together, these findings suggest that PeptiStrong™ can act as a promising adjunct to resistance training, helping to support muscle strength, endurance, and beneficial metabolic adaptations — and potentially even bone health. While the trial size was modest, the inclusion of both men and women in equal numbers strengthens the findings and broadens their relevance.
For practitioners, the takeaway is that PeptiStrong™ represents a novel, clinically studied, plant-based option that can complement foundational strategies like dietary protein and resistance training. As the research base grows, these fava bean–derived peptides may become an increasingly helpful tool for supporting healthy muscle function across a wide range of patients.
Dive into more clinical studies featuring Vicia faba bioactive peptides:
By Danielle C. Male, MS, CNS, LDN
Designs for Health has been dedicated to being the most trusted source for superior quality, science-based nutritional products for nearly three decades. We’re committed to maximizing successful health outcomes by providing healthcare practitioners with comprehensive support through our extensive product line, ongoing clinical education, and practice development programs. The blogs we publish here cover a range of topics, including new and original approaches to diet and healthcare, analyses of the latest cutting-edge research, deep-dives into specific nutrients, botanicals, nutraceuticals and more, all fully referenced for those who want to dig deeper into the primary literature.
