SA3X for Muscle Growth & Strength: What Did the 2025 Human Study Find?
A botanical extract, 546 male participants and a clinical trial investigating muscle size and strength. Could SA3X represent an interesting new direction in sports nutrition research?
Every year, the supplement industry introduces new ingredients promising improved muscle development, strength and physical performance.
But when it comes to building muscle, the scientific evidence behind many emerging ingredients is often limited to laboratory experiments or animal studies.
That's what makes the research surrounding SA3X, a patented Spilanthes acmella extract, particularly interesting.
In 2025, researchers published a randomised, placebo-controlled human study investigating SA3X supplementation and its relationship with muscle measurements, strength performance and hormonal outcomes.
The study involved 546 healthy men, making it a substantial investigation by participant count for an emerging botanical ingredient.
Researchers reported some intriguing findings.
But there's an important question worth asking:
Do these results demonstrate genuine muscle growth, or is there more to the story?
Let's examine the science.
What Is SA3X?
SA3X is a patented botanical extract derived from Spilanthes acmella, a flowering plant containing naturally occurring compounds known as alkylamides.
One of its principal bioactive constituents is spilanthol.
SA3X is standardised to contain 3.5% spilanthol, providing a defined concentration of this compound.
The extract has attracted scientific interest through human studies examining testosterone concentrations, male sexual function and physical-performance measurements.
However, SA3X is not an anabolic steroid, testosterone preparation or established muscle-building treatment.
The 2025 SA3X Muscle Growth & Strength Study
The study, titled The Effects of Spilanthol (SA3X) Supplementation on Muscle Size and Strength in Healthy Men – A Randomized Parallel-Group Placebo-Controlled Trial, investigated whether SA3X supplementation was associated with changes in muscular measurements and strength.
Study Overview
| Study characteristic |
Details |
| Publication year |
2025 |
| Participants |
546 healthy men |
| Study design |
Randomised, parallel-group, placebo-controlled |
| Ingredient |
SA3X (Spilanthes acmella extract) |
| Main outcomes |
Muscle measurements and strength |
| Additional outcomes |
Hormonal measurements |
| Study duration |
Approximately 3 months |
The researchers compared supplementation and exercise conditions to investigate differences in physical outcomes.
This design is useful because resistance training itself can produce substantial improvements in strength and muscular development.
A controlled trial can help researchers investigate whether an intervention contributes effects beyond those associated with training alone.
However, the strength of any conclusion depends on the quality of the methods, the accuracy of the measurements and the statistical analysis.
What Did Researchers Find?
The researchers reported improvements in several muscular and strength-related outcomes among participants receiving SA3X.
These included measurements associated with:
Some reported differences between groups were statistically significant.
These findings are interesting because they raise the possibility that the extract warrants further investigation in exercise-science research.
However, statistical significance alone does not establish that the observed effects are clinically meaningful or reliably reproducible.
Does Increased Muscle Circumference Mean Increased Muscle Mass?
This is one of the most important questions when interpreting the study.
Muscle circumference measurements can provide useful information, but they are not the same as directly measuring skeletal muscle hypertrophy.
For example, an increase in upper-arm circumference may reflect several factors, including:
Consequently, circumference measurements cannot independently confirm that an intervention increases lean muscle tissue.
More comprehensive research would ideally incorporate validated body-composition methods, such as MRI, ultrasound or carefully controlled DXA assessments, depending on the research question.
This distinction is especially important when a study reports unusually large changes over a relatively short period.
What About the Strength Results?
The researchers also examined strength-related measurements, including bench press and squat performance.
Strength is influenced by more than muscle size alone.
Several factors contribute to improvements in resistance-training performance, including:
Neuromuscular adaptations: The nervous system becomes more efficient at coordinating muscular contractions.
Training familiarity: Repeated exposure to an exercise can improve technique and confidence.
Muscular hypertrophy: Increases in muscle tissue can contribute to greater force-production capacity.
Programming and recovery: Training volume, intensity, fatigue management and recovery influence performance.
This means that an improvement in bench press or squat strength does not automatically demonstrate that an ingredient directly increases muscle protein synthesis or muscular hypertrophy.
To determine whether SA3X has an independent effect, researchers need to carefully control training conditions and compare changes between appropriately matched groups.
Why the Placebo Group Matters
One of the most important features of a controlled study is the comparison between intervention and placebo groups.
Imagine two groups of participants undertaking resistance training.
If both groups improve their bench press performance, the improvement itself does not demonstrate a supplement effect.
The relevant question is whether the group receiving the supplement improves more than the placebo group under comparable conditions.
Researchers must also consider baseline differences, training adherence, statistical variability and potential confounding factors.
This is why interpreting a study requires more than simply looking at the largest percentage improvement reported.
Could Testosterone Explain the Reported Results?
SA3X has also been investigated in human studies measuring testosterone concentrations.
Some published research has reported modest changes in testosterone compared with placebo.
However, a statistically significant increase in testosterone does not automatically establish a mechanism for improved muscular development.
Testosterone concentrations fluctuate naturally, and small changes within normal physiological ranges may not produce measurable differences in muscle growth or strength.
At present, there is insufficient evidence to conclude that SA3X produces meaningful muscular adaptations through testosterone-related mechanisms.
Further studies incorporating comprehensive hormonal measurements would be valuable.
What Is Spilanthol and How Might It Work?
Spilanthol is a naturally occurring alkylamide found in Spilanthes acmella.
Scientists have investigated its biological activity in laboratory and animal research.
Several potential physiological pathways have been explored, including interactions with inflammatory signalling and other cellular processes.
However, laboratory findings cannot automatically be applied to human supplementation.
There is currently insufficient evidence to establish that spilanthol directly increases muscle protein synthesis, activates mTOR signalling or reliably improves resistance-training adaptations in humans.
These remain potential areas for future investigation rather than established mechanisms.
How Strong Is the Evidence for SA3X and Muscle Growth?
The 2025 study is interesting for several reasons.
First, it involved a relatively large number of participants compared with many early-stage botanical supplement studies.
Second, it incorporated a placebo-controlled design.
Third, it examined physical-performance measurements rather than relying exclusively on subjective reports.
However, there are also important limitations.
1. Independent Replication
A single positive study cannot establish a reliable effect.
Further trials conducted by independent research groups are necessary to determine whether the findings can be reproduced.
2. Muscle Measurement Methods
Circumference measurements do not directly establish changes in skeletal muscle tissue.
More precise assessment methods would strengthen future investigations.
3. Training Variables
Resistance-training programmes can produce considerable differences in strength and muscular development.
Training volume, intensity, progression and adherence must be carefully considered.
4. Biological Plausibility
The mechanisms through which SA3X might influence muscular outcomes have not been conclusively demonstrated in humans.
5. Long-Term Safety
The available research does not establish the safety of continuous SA3X supplementation over extended periods.
The findings are interesting enough to justify further research, but they do not yet establish SA3X as a clinically proven muscle-building ingredient.
How Does SA3X Compare With Established Sports Nutrition Ingredients?
When evaluating emerging supplements, it's useful to compare the strength of their research with ingredients that have been investigated extensively.
For example, creatine monohydrate has been examined in numerous human trials across different populations and training conditions.
Its effects on high-intensity exercise performance and resistance-training adaptations are supported by a much larger body of evidence.
SA3X is at a substantially earlier stage of scientific evaluation.
That doesn't mean the ingredient has no potential.
It means that the evidence supporting its use for muscle development and strength is currently far less established.
Understanding Ultra Labs SA3X
Ultra Labs SA3X contains patented Spilanthes acmella extract standardised to 3.5% spilanthol.
The label declares the following ingredient quantities:
| Ingredient |
Per Capsule |
| SA3X Spilanthes acmella extract |
250 mg |
| Spilanthol (3.5%) |
8.75 mg |
Each bottle contains 60 capsules.
Two capsules provide a total of 500 mg SA3X extract and 17.5 mg spilanthol.
This provides a clearly declared botanical ingredient profile.
However, using an ingredient investigated in clinical research does not guarantee that a finished commercial product will reproduce the reported outcomes.
Frequently Asked Questions
Has SA3X been studied for muscle growth?
Yes. A 2025 randomised, placebo-controlled study involving 546 healthy men examined SA3X supplementation in relation to muscle measurements and strength performance.
Did the SA3X study report improvements?
The researchers reported improvements in several muscle and strength-related measurements among participants receiving SA3X.
However, the results require independent replication and careful interpretation.
Does SA3X increase muscle protein synthesis?
There is insufficient direct human evidence to establish that SA3X increases muscle protein synthesis.
Does SA3X activate mTOR?
A reliable mTOR-activating effect from SA3X supplementation has not been established in humans.
Is SA3X comparable to creatine?
No direct equivalence has been established. Creatine has a much larger and more consistent body of human research supporting its role in high-intensity exercise performance.
Can SA3X increase testosterone?
Some studies have reported modest changes in testosterone concentrations, but these findings do not establish a clinically meaningful testosterone-boosting effect.
Is SA3X research conclusive?
No. More independent trials are required to confirm the reported outcomes and establish their clinical significance.
Final Verdict: Is SA3X an Emerging Ingredient Worth Watching?
SA3X is an interesting botanical extract because researchers have investigated it in human clinical trials examining muscular measurements, strength performance and hormonal outcomes.
The 2025 study involving 546 men provides a useful starting point for further scientific investigation.
However, some reported improvements warrant additional scrutiny, particularly regarding measurement methods and reproducibility.
At present, there is insufficient evidence to conclude that SA3X reliably increases skeletal muscle mass or strength.
The next important step is independent research using rigorous body-composition assessments, controlled resistance-training programmes and clinically meaningful outcomes.
Until then, SA3X remains an emerging ingredient with intriguing preliminary findings rather than an established muscle-building supplement.
Learn More About SA3X
Interested in exploring the broader research?
What Is SA3X? Spilanthes Acmella, Spilanthol & Human Research Explained
Discover the ingredient, standardised spilanthol content and published human studies.
SA3X & Testosterone: What Do the Human Clinical Trials Actually Show?
Explore the reported hormonal findings and whether the changes are physiologically meaningful.
Ultra Labs SA3X at M&M Fitness
For readers interested in the ingredient formulation, explore the Ultra Labs SA3X product information at M&M Fitness, including its declared extract and spilanthol content.
Scientific References
Primary Study
The Effects of Spilanthol (SA3X) Supplementation on Muscle Size and Strength in Healthy Men – A Randomized Parallel-Group Placebo-Controlled Trial.
Published 2025.
https://pubmed.ncbi.nlm.nih.gov/40323176/
Additional Research
SA3X human clinical studies and testosterone research:
https://pubmed.ncbi.nlm.nih.gov/?term=SA3X+Spilanthes+acmella
Research disclaimer: This article is provided for educational purposes. The published findings do not establish that SA3X reliably increases muscle mass, strength or testosterone, or treats any medical condition. Long-term safety has not been established. Consult a qualified healthcare professional for individual medical advice.
Liam Kelly
