Irisinxd
Also known as: Irisin, FNDC5-derived hormone, Irisinxd
Overview
Irisin is an endogenous hormone, classified as a myokine, primarily secreted by skeletal muscle in response to physical activity. It is derived from the fibronectin type III domain-containing protein 5 (FNDC5). Naturally produced in the body, irisin has garnered significant scientific interest for its multifaceted roles in energy metabolism, bone health, and glucose regulation. While irisin is a well-studied physiological hormone, supplement forms marketed as "Irisinxd" are typically synthetic or recombinant analogs designed to mimic its effects. Research on endogenous irisin's physiological functions is robust, with numerous observational and mechanistic studies. However, evidence regarding the efficacy and safety of irisin as a direct supplement is still emerging, largely due to a lack of dedicated clinical trials on exogenous irisin supplementation. Most high-quality evidence, such as systematic reviews and meta-analyses, focuses on the levels of circulating irisin in response to exercise or disease states, rather than the direct effects of supplemental forms.
Benefits
Irisin, as an endogenous hormone, has been associated with several health benefits, primarily through its role in metabolic and musculoskeletal processes. For bone health, a 2024 systematic review and meta-analysis indicated a significant inverse association between higher circulating irisin levels and the risk of osteoporosis in women, suggesting its involvement in bone metabolism and remodeling. In terms of metabolic health, another extensive meta-analysis linked circulating irisin levels with improved glucose homeostasis and insulin sensitivity, particularly in relation to type 2 diabetes mellitus (T2DM). Furthermore, irisin is recognized as an exercise-induced hormone; multiple meta-analyses have shown that acute endurance exercise can increase circulating irisin levels in healthy adults, with continuous endurance training producing a moderate but significant effect. A systematic review of randomized controlled trials (RCTs) further supported that exercise interventions generally increase circulating irisin, reinforcing its role in mediating the metabolic benefits of physical activity. While these findings highlight irisin's physiological importance, it's crucial to note that these benefits are primarily observed with endogenous irisin modulated by exercise, and direct supplementation effects remain less characterized due to a scarcity of RCTs on irisin supplementation itself.
How it works
Irisin functions as a signaling molecule, primarily released by muscle cells during physical activity. Its key mechanism involves promoting the 'browning' of white adipose tissue, which leads to increased thermogenesis and enhanced energy expenditure. This process contributes to metabolic health by converting energy-storing white fat into energy-burning brown-like fat. In bone metabolism, irisin stimulates the differentiation of osteoblasts (bone-forming cells) and inhibits osteoclast activity (bone-resorbing cells), thereby contributing to bone formation and overall bone strength. Additionally, irisin plays a role in glucose metabolism by enhancing insulin sensitivity and facilitating glucose uptake in both muscle and adipose tissues. The precise bioavailability and pharmacokinetics of exogenously administered irisin (in supplement form) are not yet well-established, making it challenging to fully understand its systemic effects when supplemented.
Side effects
Currently, there are no established common or rare side effects directly attributed to irisin supplementation, primarily because no direct randomized controlled trials (RCTs) on irisin supplementation safety have been conducted. Endogenous irisin, as a naturally occurring physiological hormone, is generally considered safe within the body's regulatory mechanisms. Due to the lack of clinical data on supplemental forms, potential drug interactions and contraindications for irisin supplementation remain unknown. Safety in specific populations, such as pregnant or breastfeeding individuals, the elderly, or children, has not been studied, and therefore, its use in these groups is not recommended. Consumers should exercise caution and consult with a healthcare professional before considering any irisin-based supplements, as the long-term effects and potential risks of exogenous administration are not yet understood.
Dosage
There are no established or recommended dosing guidelines for irisin supplementation. Current scientific literature primarily focuses on the changes in circulating irisin levels in response to exercise rather than on the effects of orally or injectably administered irisin supplements. Consequently, the optimal dose, timing of administration, and most effective formulation for irisin supplementation have not been determined through clinical trials. Without specific research on exogenous irisin, there are no defined upper limits or safety thresholds for supplemental forms. Any product marketed as an irisin supplement lacks evidence-based dosing instructions, and consumers should be aware that such products are not supported by clinical data regarding their efficacy or safety at any specific dosage.
FAQs
Is irisin supplementation effective?
Current evidence supports irisin's beneficial role as an endogenous hormone, particularly in metabolic and bone health, but lacks direct clinical trials on the efficacy of irisin as a supplement.
Is irisin safe to take as a supplement?
Safety data on irisin supplements are not available from clinical trials. Endogenous irisin is a natural hormone, but the safety of exogenous supplementation is unstudied.
Can exercise increase irisin naturally?
Yes, especially continuous endurance exercise has been shown to significantly increase circulating irisin levels in healthy adults.
How quickly does irisin respond to exercise?
Acute increases in irisin levels can occur immediately post-exercise, with sustained effects depending on the duration and intensity of training.
Research Sources
- https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2024.1388717/full – This systematic review and meta-analysis found a significant inverse association between circulating irisin levels and the risk of osteoporosis in women. The study suggests irisin plays a role in bone metabolism, though it noted moderate heterogeneity across included studies.
- https://pubmed.ncbi.nlm.nih.gov/36426821/ – This systematic review and meta-analysis investigated the effect of acute exercise on irisin levels. It concluded that continuous endurance training significantly increases irisin, while interval training showed no significant change, highlighting the specificity of exercise type.
- https://onlinelibrary.wiley.com/doi/full/10.1002/rco2.70000 – This extensive meta-analysis explored the relationship between circulating irisin levels and type 2 diabetes mellitus (T2DM). It indicated that irisin may play a role in improving glucose homeostasis and insulin sensitivity, suggesting its potential as a biomarker or therapeutic target for T2DM.
- https://journals.sagepub.com/doi/abs/10.1177/10998004221142580 – This systematic review and meta-analysis focused on the impact of exercise interventions on circulating irisin. It confirmed that exercise generally increases irisin levels, supporting its role as an exercise-induced hormone with potential metabolic benefits, but did not include supplementation trials.
- https://pubmed.ncbi.nlm.nih.gov/36110558/ – This systematic review and meta-analysis of randomized controlled trials (RCTs) concluded that exercise interventions consistently increase circulating irisin. The findings support irisin's role as an exercise-induced hormone, reinforcing its importance in mediating the health benefits of physical activity.
