Irisin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Irisin is a small protein your muscles release, and people link it to exercise. Nobody has ever given it to a person. In people, the one test everyone trusts found a small rise with exercise. In mice, it made white fat burn energy like brown fat. Many blood test kits for irisin may not measure it at all.
Evidence grade for Irisin: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 1 completed trial, 7 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 7
- Human studies
- 1
- Found nothing
- 0
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
1 completed trial, 7 people given it
2 effects reported, 2 unwanted, by people using it, not a trial
Goal pages: Muscle and strength, Brain, memory and mood, Ageing and longevity
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Irisin is a small protein your muscles give off, and it is linked to exercise. In mice, it makes white fat burn energy like brown fat. Nobody has ever given it to a person. Many blood tests for it may not even measure it.
What people take it for
- Getting the good of exercise without doing the exercise.
- Burning more fat.
- Checking a blood number that is sold as a sign of fitness.
What studies in people showed
Nobody has tested irisin as a treatment in people. Since nobody can patent it, nobody is likely to pay for that study. What we have are blood tests. The one test everyone trusts found about 3.6 ng/mL in people who sat most of the day. People doing interval cardio had about 4.3. Most other studies used store-bought kits, and a 2015 check found those kits pick up the wrong proteins. Reviews of exercise studies do not even agree. One review of 173 people found training lowered irisin. A review of 1,780 people found it raised it. The fat, bone and memory effects are all in mice.
What people report
Reports, not study results
The good
- We have not collected user reports on this one yet.
The bad
- Nobody has been given irisin in a study, so there is no side effect data at all.
- Blood test kits for irisin may give you a number that is not irisin.
Where these come from: There are no user reports on this page. The kit warning comes from the 2015 antibody study on this page.
My bottom line
Exercise works. A bottle sold as the exercise hormone has not one human study behind it. Train, and skip the vial.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Animal and lab work, not yet tested in people
Real results, but from animals or cells, not people. What works in a mouse often does not work the same way in a person. Nobody can patent this, so nobody would ever earn back the cost of a study in people. That is usually why there is none. The record on this one is set out below.
- Cell energy and mitochondria1 animal or lab study
- Lasting longer, stamina1 animal or lab study
- Memory and thinking1 animal or lab study
33 of the 36 indexed goals have no study of any kind behind Irisin
No study in people, animals or cells on this page reports a result for these. That does not prove Irisin does nothing for them. It does mean anything you have heard about Irisin and one of these did not come from a study cited here.
Show full evidence
What is Irisin?
Irisin is a small protein your muscles release, and people link it to exercise. Nobody has ever given it to a person. In people, the one test everyone trusts found a small rise with exercise. In mice, it made white fat burn energy like brown fat. Many blood test kits for irisin may not measure it at all.
Irisin is a piece cut off a muscle protein called FNDC5. Scientists first described it in 2012. The story was simple. Exercise makes muscle release irisin, and irisin makes fat burn more energy. That is why the word turns up on supplement labels and blood test panels.
Nobody has ever given irisin to a person. We searched the US trials register on 11 September 2026. It listed dozens of studies that measure irisin in the blood after exercise, diet or illness. None of them gives it. So everything known in people is about how much is in the blood, not what it does.
The best measurement in people came in 2015. The lab that found irisin weighed it directly with a lab machine, not with a test kit. People who sat most of the day had about 3.6 ng/mL in their blood. People doing interval cardio had about 4.3 ng/mL. That is roughly 19 percent more. It shows irisin is real in people. It does not show that it does anything.
Most other irisin numbers come from store-bought test kits. Also in 2015, Albrecht and colleagues tested four of the antibodies those kits rely on. The antibodies stuck to the wrong proteins in blood. They also missed pure irisin when it was put in front of them. The team said all earlier kit results were in doubt. Both papers are described in full below.
Three reviews pooled exercise studies, and they do not agree. A 2015 review of 3 studies in 173 people found training lowered irisin. A 2021 review of 7 weight training studies in 282 people found a small rise that could be chance. A 2026 review of 50 studies in 1,780 adults who were overweight or obese found a moderate rise. All of them lean on the doubtful kits. None measured anyone's health.
Everything else is in mice. That includes the docking site, the bone effects, the muscle loss work and the memory work in mice bred to get Alzheimer's. Irisin is not approved anywhere, and no company is developing it. Anything sold as irisin is unregulated.
How does Irisin work?
In people, the very first step is in doubt. The human irisin gene has a broken start signal. In a dish, that broken signal made only about 1 percent of the normal amount of protein. In two human exercise studies, the gene did not get more active in muscle after cardio or weight training. In a dish, irisin did not turn human fat cells into energy burning fat, while a different protein called BMP7 did. The 2015 weighing study says human irisin is still made from that odd start signal. Nobody has found an irisin docking site in human tissue. Nobody has shown irisin does anything in a person. In mice, the story goes like this. Exercise turns up a muscle switch called PGC-1alpha. That switch makes more FNDC5. The outer part breaks off as irisin. Irisin tells white fat to act like brown fat and burn energy. That raised energy use and helped blood sugar in mice. A 2018 paper found a docking site for irisin on mouse bone and fat cells. Other mouse work reports effects on bone cells, on muscle loss with age, and on memory in mice bred to get Alzheimer's.
What have studies in people found about Irisin?
Nobody has ever given irisin to a person. The human studies only measure how much is in the blood. Most used store-bought kits, and a 2015 study showed those kits may not measure irisin. One 2015 study weighed irisin directly and showed it really is in human blood.
- A 2026 review pooled 50 exercise studies in 1,780 adults who were overweight or obese. Training raised irisin in the blood by a moderate amount.
- A 2021 review pooled 7 weight training studies in 282 people. Irisin rose a little, but the rise could have been chance. Every study used test kits.
- A 2015 review pooled 3 studies in 173 people. Training lowered irisin in the blood.
- Weighing it directly (Cell Metabolism 2015): about 3.6 ng/mL of irisin in people who sat most of the day and about 4.3 ng/mL in people doing interval cardio. This is the only method whose accuracy nobody disputes.
- Muscle samples from people (PLoS One 2013): in two separate exercise studies, the irisin gene was no more active after cardio or weight training.
- Test kit check (Scientific Reports 2015): the antibodies in four store-bought kits stuck to the wrong blood proteins and missed pure irisin. Every kit-based irisin number carries this doubt.
- US trials register, searched 11 September 2026: dozens of studies measure irisin in the blood after exercise, diet or supplements. None gives irisin to anyone.
What this does not tell you: Nothing here shows irisin does anything in a person. The exercise studies measured a number in the blood. They did not measure fat burning, energy use, weight, bone or thinking. Almost all of them used kits that may not measure irisin. The three reviews do not even agree on whether training raises it or lowers it. The weighing study shows irisin is there and moves a little with exercise. It does not show what it does. There is no dose, no safety data and no data on how long it lasts in the body, because nobody has ever given it to a person.
The state of the research
This page reports an argument, and both sides deserve a fair hearing.
The doubt came in two parts. In 2013 a German team showed the human irisin gene has a broken start signal. In a dish, it made only about 1 percent of the normal protein. They also found the gene did not get more active in human muscle after training, and irisin did not change human fat cells in a dish. In 2015 Albrecht, Norheim, Thiede and colleagues went after the blood tests. The antibodies in four store-bought kits stuck to the wrong proteins and missed pure irisin. So, in their words, all earlier kit results were in doubt. Their paper called irisin a myth.
The answer came the same year from the lab that discovered irisin. That lab has a clear stake in the result. It also knows the molecule best. Jedrychowski, Wrann, Paulo and colleagues skipped antibodies and weighed irisin directly with a lab machine. They found about 3.6 ng/mL in people who sat most of the day and 4.3 ng/mL in people doing interval training. That settles that irisin exists in people. It does not show what it does. It does not rescue any kit study. And a rise of 0.7 ng/mL with exercise is small next to what is promised when irisin is sold. A 2021 review of the field treats both sides as still open. We report both and do not pick a winner.
The money side is simple. Irisin is a natural piece of a human protein, so nobody can patent it. No company has a reason to pay for the study that would test giving it to people, and none has. A missing study is not proof either way. Meanwhile, more and more papers quote irisin numbers from kits nobody has rechecked. Any page or product that quotes a kit number for irisin should carry the Albrecht warning.
The evidence, in charts
Fig. 1a · how many people
60people, across 3 studies in people cited here
| Study | People | Share |
|---|---|---|
| Sports Medicine 2026 | 50 | 83% |
| International Journal of Environmental Research and Public Health 2021 | 7 | 12% |
| Sports Medicine 2015 | 3 | 5% |
One study holds 83% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. 1 more study in people gives no headcount and is not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
4 of 10 sources here are studies in people. The rest are not.
- Study in people · done in people440%
- Animal study · done in animals330%
- Lab (cells in a dish) · cells or tissue220%
- Review of studies · sums up other studies110%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 7 different years, 2012 to 2026, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Biologic
- Molecule weight
- 28,283 Da (FNDC5 precursor, 260 residues, UniProt Q8NAU1); the mass of the circulating fragment depends on which of two length conventions is used
- Half-life
- None on file
- Chain length
- None on file
No amino acid sequence is on file for Irisin, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2015Detection and Quantitation of Circulating Human Irisin by Tandem Mass Spectrometry
Irisin really does circulate in people, and exercise nudges it up. The lab that discovered the hormone weighed it directly with a lab machine, a harder test than the kits most irisin papers use. People who sat most of the day carried about 3.6 nanograms per millilitre. People doing interval cardio carried about 4.3. This settles that irisin exists and that training moves it. It does not show that raising it does anything for you. Public money paid for the work.
From the laboratory that discovered irisin. Mass spectrometry with heavy stable isotope internal standards found human irisin at about 3.6 ng/mL in sedentary people and about 4.3 ng/mL in people doing aerobic interval training, and reported it is mainly translated from the non-canonical ATA start codon. The authors' conclusion: human irisin exists, circulates and is regulated by exercise. NIH and non-US government funded.
- Study in people2015Chronic Exercise Training and Circulating Irisin in Adults: A Meta-Analysis
Pooling the studies gave the opposite of what the irisin story predicts. Three studies in 173 healthy people who did not train were combined. Eight weeks or more of training left irisin lower than in people who did not train. Nine looser studies in 113 people found no change. Every study used test kits, which other work shows may read the wrong thing.
3 randomised trials (173 healthy untrained participants): at least 8 weeks of training was associated with lower circulating irisin than control (Cohen's d -0.46, 95 percent CI -0.76 to -0.15). 9 non-randomised studies (113 participants) showed no change (d -0.04). All studies used immunoassays.
- Study in people2021Effect of Chronic Resistance Training on Circulating Irisin: Systematic Review and Meta-Analysis of Randomized Controlled Trials
Weight training may raise irisin, but the result is too weak to call. Seven studies covering 282 people were combined. Irisin came out a little higher after at least eight weeks of weight training. The rise was so small it could have been chance. Every study used test kits. The authors say someone needs to weigh irisin directly before anybody answers this.
7 randomised trials, 282 people, all using ELISA kits by inclusion criterion: a non-significant increase after at least 8 weeks of resistance training (d 0.58, 95 percent CI -0.25 to 1.40, p 0.17). The authors call for mass spectrometry in future studies.
- Study in people2026Effects of Different Training Modalities on Circulating Irisin Levels in Overweight and Obesity Adults: A Systematic Review and Meta-analysis of Randomized Controlled Trials
This is the largest pool of exercise studies yet, and it points the other way. Fifty studies covering 1,780 adults who were overweight or obese were combined. Training left irisin higher than in people who stayed inactive. The 2015 pool found the opposite. When two big summaries of the same kind of study disagree, the test itself is likely unreliable. Note what was counted: irisin in the blood, not anybody's health.
50 randomised trials, 1,780 adults with overweight or obesity: exercise training was associated with higher circulating irisin than passive control (standardised mean difference 0.62, 95 percent CI 0.39 to 0.85). The direction is opposite to the 2015 meta-analysis. Irisin was measured as a biomarker; no clinical outcome was pooled.
- Review of studies2021Progress and Challenges in the Biology of FNDC5 and Irisin
A review of the whole field. It treats the broken start signal, the kit problem and the direct weighing answer as open questions, not settled ones.
The field-level review that treats the start codon objection, the antibody objection and the mass spectrometry rebuttal as open questions rather than settled ones.
- Animal study2012A PGC1-alpha-dependent myokine that drives brown-fat-like development of white fat and thermogenesis
In mice. This is the first irisin paper. Exercise made mouse muscle release irisin. Irisin made white fat act like brown fat and burn more energy. The mice did better on weight and blood sugar. Public money paid for the work.
The original report. In mice, exercise-induced PGC-1alpha raised FNDC5 in muscle; its cleaved product, named irisin, induced UCP1 and a brown-fat programme in white fat, increased energy expenditure and improved obesity and glucose homeostasis. NIH and non-US government funded.
- Animal study2018Irisin Mediates Effects on Bone and Fat via alpha-V Integrin Receptors
In mice. This paper found where irisin docks on mouse bone and fat cells. Nobody has found that docking site in human tissue.
Identification of alpha-V integrins as irisin receptors in mouse osteocytes and fat cells. The receptor has not been demonstrated in human tissue.
- Animal study2019Exercise-linked FNDC5/irisin rescues synaptic plasticity and memory defects in Alzheimer's models
In mice bred to get Alzheimer's. Irisin brought back memory and the way brain cells connect. Mice only.
In mouse Alzheimer's disease models, FNDC5/irisin restored synaptic plasticity and memory. Mouse only.
- Lab (cells in a dish)2013Evidence against a beneficial effect of irisin in humans
Mostly in a dish, plus muscle samples from people. The human irisin gene has a broken start signal. With that signal, cells in a dish made only about 1 percent of the normal protein. In muscle samples from two human exercise studies, the gene did not get more active after cardio or weight training. In a dish, irisin did not turn human fat cells into energy burning fat. Public money paid for the work.
Human FNDC5 has an ATA rather than ATG start codon; a human construct with ATA produced about 1 percent of full-length protein. FNDC5 mRNA in human muscle biopsies from two exercise studies was unchanged by endurance or strength training, and recombinant FNDC5 or irisin did not brown human preadipocytes where BMP7 did. Non-US government funded.
- Lab (cells in a dish)2015Irisin, a myth rather than an exercise-inducible myokine
A lab check of blood samples. The antibodies in four store-bought irisin kits stuck to many wrong proteins in human and animal blood. They missed pure irisin when it was added as a check. A lab machine did find a trace of the parent protein in human blood, but the antibodies did not. The authors said all earlier kit results were in doubt. Public money paid for the work.
Four commercial polyclonal antibodies used in irisin ELISA kits showed prominent cross-reactivity with non-specific proteins in human and animal sera on Western blot; with recombinant glycosylated and non-glycosylated irisin as positive controls, no band of the expected size appeared in any biological sample. A FNDC5 signature at about 20 kDa was found in human serum by mass spectrometry but was not detected by the antibodies. The authors concluded that all previous data from commercial irisin ELISA kits was called into question. NIH and non-US government funded.
Common questions
Has Irisin been tested in people?
Yes. 7 people given it across 1 completed trial cited here, 0 of which found nothing. Irisin is a small protein your muscles release, and people link it to exercise. Nobody has ever given it to a person. In people, the one test everyone trusts found a small rise with exercise. In mice, it made white fat burn energy like brown fat. Many blood test kits for irisin may not measure it at all.
What is the Irisin dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 1 completed trial, 7 people given it
Is Irisin FDA-approved?
Not FDA-approved. No irisin product is approved anywhere, or being tested in any registered human study. No study has ever given irisin to a person.
Does exercise raise irisin in humans?
Yes, a little. The one test nobody disputes weighed irisin directly. People doing interval cardio had about 4.3 ng/mL. People who sat most of the day had about 3.6 ng/mL. That is roughly 19 percent more. Reviews of exercise studies using store-bought kits disagree. A 2015 review found training lowered irisin. A 2026 review of 50 studies found it raised it. In 2015 the kits those reviews rely on were shown to pick up the wrong blood proteins.
Has irisin ever been given to a person?
No. No published study and no registered trial has given irisin to a person. Every human study measures how much is in the blood after exercise, diet or illness. The effects on fat, bone, muscle and memory all come from mice.
Is irisin a myth?
That was the title of a 2015 paper. It showed that store-bought irisin antibodies do not pick out irisin cleanly. The same year, the team that discovered irisin weighed it directly and found a few nanograms per millilitre in human blood. So irisin does exist in people. Whether it does anything in people has never been tested.
Should I trust an irisin blood test?
Be careful if it is a store-bought kit test. A 2015 study found the kits it checked picked up other blood proteins and missed pure irisin. Nobody outside has rechecked those kits since. Weighing it directly by lab machine is the only method known to be accurate, and you cannot order that as a routine test.
Why is there no irisin drug or trial?
Irisin is a piece of a human protein, so nobody can own it. No company has paid for a study that gives it to people. That leaves the question open both ways. Without a study, nobody has looked for benefit or harm in people.