Learn how 6′-sialyllactose (6′-SL), a human milk oligosaccharide, supports muscle health, recovery, and strength at the molecular level.
Content Outline
Maintaining muscle strength is something many people take for granted, at least until weakness sets in. For individuals living with a rare, inherited disorder called GNE myopathy, which causes progressive muscle wasting, even simple movements can become challenging over time. Despite ongoing research, there is currently no cure for the disease [1], and treatment focuses on managing symptoms and slowing its advance.
However, a study published in 2023 has shed light on a promising approach using human milk oligosaccharides, specifically 6’-sialyllactose (6’-SL). This naturally occurring compound found in human breast milk could help improve the biochemical properties of sialic acid and minimise the impact of muscle degeneration.
Here, we explore the study further and what this could mean for the future of GNE myopathy.
What is 6′-sialyllactose?
6’-sialyllactose or 6’-SL for short, is a type of human milk oligosaccharide that’s found abundantly in human breast milk. HMOs are bioactive compounds that are known for supporting the initiation of the infant gut microbiome, brain development, and immune function. But emerging evidence shows they also hold benefits far beyond early life, including for muscle maintenance and recovery [2].
6’-SL is a sialylated HMO, which means it contains sialic acid at its core, a key molecule that builds glycoproteins and glycolipids in the body. The components are critical for muscle cell membranes and communication systems [3]. If you don’t have enough sialic acid, muscle tissues can weaken, become less able to repair themselves, and be prone to degeneration.
Figure 1. Chemical structure of 6’-SL.
6’-SL is also a prebiotic energy source for your gut bacteria, helping to build a strong colonic ecosystem. In doing so, tiny molecules support your overall health, immunity and cognition.
Understanding GNE myopathy and the role of sialic acid
GNE myopathy, previously known as hereditary inclusion body myopathy (HIBM), is a rare, inherited condition that causes muscle degeneration. It’s caused by mutations in the GNE gene, which encodes the enzyme essential for producing sialic acid in the body. When this enzyme does not work properly, sialic acid levels fall, leading to gradual muscle weakness, particularly in the limbs.
Latest figures suggest that GNE myopathy affects 18 people per million, but this is a conservative estimate, and it could be much higher [4].
Sialic acid is not just a structural sugar; it has important roles in:
Previous studies have investigated the effects of supplementing with sialic acid precursors, such as N-acetylmannosamine, but with little success. That’s why researchers are now turning to 6’-SL, a naturally sialylated molecule that can directly deliver sialic acid in a form the body already recognises and uses efficiently.
What the research says: 6′-Sialyllactose in GNE Myopathy
In 2023, the results of a randomized pilot trial were published. The study investigated the efficacy and safety of oral 6’-SL in GNE myopathy patients. The individuals were either given a low-dose 3g or a high-dose 6g single-dose supplement of 6’-SL. Blood plasma levels of 6’-SL, sialic acid, and sialic acid levels on the surface of red blood cells were measured periodically throughout the trial.
The researchers found that 6’-SL was well tolerated and safe, with no major adverse events or safety issues reported. The most common side effects were gastrointestinal issues and headaches. However, these were mild and self-limiting.
Following 6’-SL supplementation, plasma levels increased within 30 minutes to 1 hour, and sialic acid concentration slowly rose over 6 to 8 hours, peaking 10 hours after administration. The bioavailability of 6’-SL was further evidenced by the fact that sialic acid levels bound to the membranes of red blood cells also increased.
The daily 6g dose of 6’-SL resulted in improved proximal limb powers, including:
The lower dose of 3g per day also improved knee extensor power and stabilised the other muscle powers. Although the 6g dose was superior, both doses had reported benefits.
Furthermore, the researchers discovered a dose-dependent protective effect of 6’-SL against muscle degeneration. Therefore, these results suggest that 6’-SL could be a good therapeutic candidate for GNE myopathy [5].
What does the latest research say?
One of the limitations of the 2023 study was that it had no placebo arm, which means there was no baseline for comparison. So, the researchers also started a placebo-controlled study to provide further evidence of the therapeutic effects of 6’-SL. The results were published in January 2025.
An overview of the results of the study was:
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Muscle strength
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No significant difference between groups (minimal decline overall).
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Hand grip strength declined significantly in the placebo group (p = 0.0004), not in the 6’-SL group.
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Muscle MRI (fat fraction — indicator of muscle degeneration):
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Posterior thigh: Significant difference between groups (p = 0.0004).
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Other regions (anterior thigh, lower legs): No statistical difference, but the 6’-SL group showed a slower increase in fat fraction from 24–36 weeks.
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Biochemical results:
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Evidence of resialylation in 6’-SL group (restoration of cell surface sialic acid).
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Patient-reported outcomes (GNEM-FAS):
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No statistically significant difference overall.
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Self-care and upper extremity scores showed signs of improvement after 24 weeks in the 6’-SL group.
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These results show that 6’-SL had less of an impact on muscle strength, likely because the study was shorter and included early GNE myopathy patients. However, it still offered promising insights into the benefits of 6’-SL for this group and demonstrates that it could have long-term benefits [6].
Beyond GNE myopathy: Supporting muscle health for everyone
Although this trial focused on GNE myopathy, the benefits of 6’-SL could extend much further. Sialic acid plays an important role in muscle metabolism, repair, and communication in everyone.
With age, stress, and even intense exercise, sialic acid metabolism can become less efficient, contributing to muscle fatigue, slower recovery, and reduced performance. Supporting the body’s natural sialic acid pathways could have benefits for all.
A recent animal study found that supplementation of 6’-SL for 12 weeks improved:
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exhaustive treadmill performance
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grip strength
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muscle mass in the gastrocnemius and soleus muscles
Overall, 6’-SL administration increased running distance and time by enhancing muscle mass and strength [7]. Therefore, 6’-SL could also be a good agent for improving muscle performance and strength, particularly in athletes.
Why choose Layer Origin’s 6′-sialyllactose HMO for muscle strength
If you’re interested in capturing the benefits of 6’-SL ,our 6’-sialyllactose HMO for Muscle Strength supplement is designed to deliver this sialylated HMO in a pure, clinically relevant, and highly bioavailable form.
We produce 6’-SL using precision fermentation technology to ensure it is:
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100% bioidentical to the 6’-SL naturally found in human milk
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Produced under strict quality and purity standards
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Free from artificial additives.
But don’t just take our word for it, here’s what some of our customers have told us:
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“This absolutely makes your pre-workout ‘hit-different’ 😂💛💪🏻” - Justin Tokarz
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“I am 75 years old and have been trying to resolve the weakness in my legs to improve walking and stair climbing. In the few weeks I’ve been taking this I have seen great improvements!” - GIs
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“So far, I’m loving this product! I’ve noticed an increase in muscle recovery after exercise & have gained strength in my lifts. I will definitely keep this supplement in my stack because I know it’s helping. Thank you for making such a great product available!” - Abraham Meza
Summary: The future of muscle health and sialyllactose
The current and emerging research into the benefits of HMOs like 6’-SL is promising. These natural components can influence muscle biology in ways that previously researched molecules have not. From rare diseases like GNE myopathy to everyday muscle maintenance, 6’-SL is offering a new kind of support to help naturally restore sialic acid levels.
Come and join the movement for better muscle strength and order your pot of 6’-sialyllactose HMO for Muscle Strength today!
Written by: Leanne Edermaniger, M.Sc. Leanne is a professional science writer who specializes in human health and enjoys writing about all things related to the gut microbiome.
