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Tier D Metabolic

Irisin

FNDC5 Cleavage Product — Exercise Hormone

Exercise-induced myokine — drives WAT-to-BAT conversion, bone health, and cognitive enhancement via exercise mimicry.

Tier D — Preclinical Only: Animal or in-vitro data only. How our tiers work →

Research facts

Half-life~few minutes
RouteSubQ (animal studies) / No injectable form validated
Typical doseNo established human injectable dose
FrequencyN/A
SolventN/A
pHN/A
StabilityUnknown

Mechanism of action

Irisin is a myokine cleaved from the membrane protein FNDC5 during exercise (particularly aerobic exercise). It drives white-to-brown adipose tissue (WAT→BAT) conversion via upregulation of UCP1, increasing thermogenesis and energy expenditure. It also promotes osteoblast differentiation and bone formation, and has documented hippocampal BDNF upregulation — explaining in part why aerobic exercise improves memory and cognition. Irisin's existence as a true circulating hormone was initially controversial (no irisin in mice), but robust human data now confirms its presence and exercise-dependent regulation.

Documented effects (research-model)

  • WAT→BAT conversion (browning of fat) for thermogenesis
  • Bone density promotion via osteoblast activation
  • Hippocampal BDNF upregulation (exercise-cognition link)
  • Insulin sensitivity improvement
  • Potential in metabolic syndrome and obesity

Research protocols

ProtocolDoseFrequencyCycleVial
Exercise (Primary Protocol) Aerobic exercise 3–5×/week is the validated method to elevate irisin Regular structured exercise Ongoing N/A

Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.

Synergies

  • NAD+ MODERATE
    Exercise (irisin) + NAD+ (mitochondrial support) are complementary healthspan interventions.

Myths & misconceptions

Myth You can inject irisin to get the benefits of exercise.
Reality Irisin has an extremely short half-life and rapidly degrades. No validated injectable human protocol exists. The best way to elevate irisin is aerobic exercise — which is why it is called an "exercise hormone".

Evidence gaps

  • No validated human injectable protocol.
  • Irisin assay variability across studies — measurement methodology inconsistencies.
  • WAT browning effects in humans less dramatic than in rodents.

Safety notes

No reliable injectable form available. The "irisin injection" research chemical market is not scientifically validated. Endogenous elevation via exercise is safe and evidence-based.

Biomarkers to monitor

HbA1cFasting GlucoseHOMA-IRTriglyceridesBone density markers

Primary-source citations

  • PMID 22012248 — A PGC1-α-dependent myokine that drives brown-fat-like development of white fat (Nature. 2012)

Frequently asked

What is Irisin?

Irisin (FNDC5 Cleavage Product — Exercise Hormone) is a research compound classified in our library as Tier D — Animal or in-vitro data only.. Exercise-induced myokine — drives WAT-to-BAT conversion, bone health, and cognitive enhancement via exercise mimicry.

What is the evidence tier for Irisin?

We classify Irisin as Tier D: Animal or in-vitro data only. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.

What is the research dose of Irisin?

For Irisin, typical research dose is No established human injectable dose, route is SubQ (animal studies) / No injectable form validated, half-life is ~few minutes. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.

Is Irisin safe?

No reliable injectable form available. The "irisin injection" research chemical market is not scientifically validated. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.

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