Samyang Roundsquare debuts Spindle supplement with gut-muscle axis postbiotic
Key takeaways
- Samyang Roundsquare launched Spindle Muscle+, a postbiotic supplement targeting the gut-muscle axis to improve muscle strength.
- Clinical trials show its active ingredient increases muscle power and significantly reduces myostatin, a protein that limits muscle growth.
- The shelf-stable supplement targets proactive adults and GLP-1 users seeking to preserve lean muscle mass.
South Korea’s Samyang Roundsquare has launched its metabolic health brand Spindle, marketed as the first postbiotic supplement targeting muscle building through the gut. Its flagship product, Spindle Muscle+, is formulated with Akkermansia MYO, a clinically studied, pasteurized form of Akkermansia muciniphila bacteria that supports muscle strength via the gut.
The company positions the supplement as a “fundamentally new perspective” on bodybuilding, which has traditionally focused on eating more protein and lifting more weight.
The brand highlights emerging research suggesting a “gut-muscle connection.” This axis of these two health areas is a critical driver in muscle health, regulating protein synthesis, systemic inflammation, and building and preserving muscle, according to the company.
“Muscle health is influenced by biological systems we’re only beginning to fully understand, including the gut-muscle connection,” says Ahjin Kim, head of R&D, Samyang Healthcare.

“The clinical research behind Akkermansia MYO gave us the evidence we needed to bring that science into a product people can trust. Spindle Muscle+ reflects our commitment to formulating from data, not assumptions.”
Addressing underlying biological systems
Samyang Roundsquare highlights that muscle strength decline can begin as early as the mid-30s, progressing steadily with age. It notes that this loss impacts anything between mobility, metabolic health, and overall health span.
While many supplements focus on isolated nutrients, such as protein or amino acids, few address the underlying biological systems that influence muscle function, underscores the company.
Akkermansia MYO is a pasteurized postbiotic derived from A. muciniphila, a beneficial microbe extensively studied for its role in gut barrier integrity and metabolic health. Notably, Akkermansia levels naturally decline with age, adds Samyang Roundsquare.
“Maintaining muscle strength over time depends on more than protein and staying active alone,” says Faissal Tahiri, head of Health Care at Samyang America.
“With Spindle, we are bringing forward a science-led approach that looks at the biological systems influencing muscle function, including the growing scientific understanding of the gut-muscle connection.”
Rounds of research
Researchers have evaluated Akkermansia MYO using multiple research, testing, and randomized, placebo-controlled clinical trials for proving efficacy and safety.
Spindle Muscle+ contains Akkermansia MYO, a postbiotic supporting muscle strength through the gut.Results from a 12-week, randomized, double-blind, placebo-controlled clinical study in adults over 60 reveal that supplementing with Akkermansia MYO leads to an 10.4% increase in hamstring strength versus a control, 14.1% increase in muscle power, 5% increase in grip strength, and 5.6% increase in prealbumin levels — a biomarker for muscle maintenance and repair.
The supplement was also associated with a significant decrease of 37.8% in myostatin levels, which serve as a biomarker for muscle strength. Elevated levels limit muscle growth.
For next-gen biohackers
Spindle targets health-conscious consumers who are primarily in their 40s and 50s and proactively explore preventative nutritional approaches to longevity, instead of reacting to bodily decline.
Spindle Muscle+ is also suitable for adults using GLP-1 weight loss medications, who face an increased risk of lean muscle loss.
Unlike traditional probiotics, Spindle Muscle+’s heat-stabilized postbiotic helps it retain shelf-stable potency and precision dosing for up to two years without refrigeration for convenient, consistent support, according to its manufacturer.
Spindle Muscle+ is marketed as gluten-free, non-GMO, free from common allergens (egg, soy, wheat, nuts, fish, and shellfish), and without artificial sweeteners, color additives, or preservatives.
Biotics beyond the gut
Commercial biotics are continually expanding beyond the gut into diverse health areas that are not commonly associated with digestion. For example, biotech company Sōlaria Biō published clinical findings supporting the gut delivery and efficacy of two synbiotic products targeting the gut-bone axis.
The first is SBD111, marketed as Bōndia, which is Sōlaria Biō’s plant-sourced synbiotic proven to improve bone density in women with osteopenia by 85%. The second is a synbiotic formulation still under development, SBD121, specifically designed for the dietary management of rheumatoid arthritis.
To advance and support this new influx of microbiome health solutions, scientists have created HaPaPro, a tool that identifies beneficial microbes using over 1,000 computer models. Recently, their analysis of over 350 products from US drugstores revealed that probiotic supplements contain limited microbial diversity and lack a clear link to the intended health benefit.
Upcoming webinars

The science of HMOs – A novonesis webinar featuring new clinical findings and ESPGHAN highlights
Novonesis

From boosters to companions: GLP-1 in Food, Beverages and Supplements
Rousselot

Top Nutrition Trends 2027
Nutrition Insight













