by Matt Weik, BS, CSCS, CPT, CSN
When you think about building muscle, what comes to mind? Probably protein shakes, heavy weights, and long training sessions, right? But what if something a little more unconventional could help? Recent research on Lemon Myrtle Extract suggests that you can improve muscle growth (especially for older adults or anyone limited in how much they can exercise).
A new study published in the Journal of Nutrition, Health and Aging looked at how this botanical ingredient might support muscle hypertrophy when paired with resistance training. And while the results weren’t the same across the board, the findings were interesting enough to put Lemon Myrtle Extract on the radar for aging populations or those dealing with low training capacity.
In this article, I want to dive deeper into this study on Lemon Myrtle Extract and help you decide whether this unique ingredient is worth adding to your supplement regimen.
Disclaimer: This article is for informational purposes only and should not be used to treat or diagnose any condition. It is recommended that you speak with your doctor before starting any exercise program, making changes to your nutrition plan, or adding any new supplements into your current regimen.
What Makes Lemon Myrtle Extract So Interesting?
Lemon Myrtle Extract comes from the Backhousia citriodora leaf and is known for its antimicrobial, anti-inflammatory, and antioxidant properties. Researchers in Japan have also studied its effects on muscle wasting in animals. They focused on an active compound in the extract called casuarinin.
In previous studies, casuarinin appeared to activate skeletal muscle satellite cells and support protein synthesis (both key aspects of muscle growth). That earlier research is what laid the groundwork for the human trials that were recently completed and talked about in this article.
But why does this matter?
This matters because many older adults struggle with both physical and mental frailty that can reduce appetite, protein intake, and overall nutrient absorption. And in certain cases (such as chronic kidney disease), protein intake is intentionally restricted. For those individuals, conventional strategies for muscle maintenance aren’t exactly straightforward.
That’s why researchers described this approach as different from the usual nutritional playbook. Instead of relying on more protein or high-volume training, Lemon Myrtle Extract may offer support through a separate physiological pathway.
The Lemon Myrtle Extract Study Design
To investigate how Lemon Myrtle Extract works, researchers ran two randomized, double-blind, placebo-controlled studies. A total of 125 Japanese adults aged 65 or older participated. All of them reported experiencing declines in muscle mass (a common concern in aging populations).
Across both studies, participants completed bodyweight resistance training twice a week for 12 weeks. The difference came down to training volume.
Study One: Typical Volume Training
The first study compared:
- Lemon Myrtle Extract with a typical training volume of three sets.
vs. - A placebo group is completing the same exercise routine.
Study Two: Low-Volume Training
The second study compared:
- Lemon Myrtle Extract with low-volume training (one set).
vs. - A placebo group is also performing just one set.
The supplement used in both trials was supplied by Kaneka Corporation. Participants took two capsules per day, and each capsule contained 1.25 mg of casuarinin.
Researchers focused on anterior thigh muscle thickness as the primary measurement. For secondary markers, they tracked body composition and physical function, including walking speed.
What Did the Study Results Show?
The real standout findings came from the second study (the group performing low-volume resistance training). Those taking Lemon Myrtle Extract saw a significant increase in anterior thigh muscle thickness compared to placebo.
In the first study, the Lemon Myrtle Extract group also saw a greater increase than the placebo group, but those changes didn’t reach statistical significance.
As for the secondary outcomes (body composition changes and functional improvements), there were no meaningful differences between groups.
So, what does that mean?
For older adults with reduced training capacity, Lemon Myrtle Extract may give low-load training a boost. In other words, the less someone can do physically, the more value this extract may offer in the muscle growth equation. But for those who are able to train at higher volumes, the impact appears limited.
How Lemon Myrtle Extract Fits into the Bigger Picture
The findings highlight a unique niche for Lemon Myrtle Extract. It might not replace resistance training or protein intake, but it could complement low-intensity exercise for older or limited-capacity individuals (perhaps those with a disability or injury).
It’s an interesting concept: enhancing hypertrophy without increasing exercise volume or relying heavily on protein. The researchers emphasized that this is a very different strategy from the traditional nutrition-first approach to muscle health.
However, they also pointed out that the study didn’t evaluate Lemon Myrtle Extract on its own, meaning the effects without exercise remain unknown. More research is needed to fully understand its clinical relevance and how it may apply to broader populations.
Not Exactly Promoted for Bodybuilding Purposes
Lemon Myrtle Extract isn’t your typical muscle-building supplement that you’d find gym rats and bodybuilders using. But for the older adults in this research, it showed potential (especially when paired with low-volume resistance training).
As always, this is early evidence, and more studies will be essential before any concrete recommendations can be made. Still, when you see an ingredient that supports hypertrophy under low-load conditions, it grabs your attention and is worth showcasing.
For now, Lemon Myrtle Extract continues to be an intriguing option worth watching, particularly for aging individuals looking to maintain muscle without intense training demands.
