BlessUp Peptide Library · Strength & Growth
Follistatin, ACE-031, IGF-1 LR3, and MGF. Four peptides sold as shortcuts to muscle, and the honest evidence is thin.
Bigger is not the same as stronger, and a signal that says "grow" to every cell is not a free lunch.
Myostatin blockade reliably adds muscle mass, but human trials repeatedly failed to turn that into strength, and the one in-class human program (ACE-031) was stopped over bleeding side effects. The growth-factor members have no human muscle trials at all. Full citations at the end.
You have seen them sold as the cheat code: Follistatin, ACE-031, IGF-1 LR3, and MGF, peptides that promise to override your body's limits and pack on muscle faster than training alone ever could.
Here is the honest version. These four split into two completely different strategies. Follistatin and ACE-031 are myostatin inhibitors: they release a natural brake. Your body makes a protein called myostatin whose whole job is to LIMIT how much muscle you build, and these mop it up so the brake comes off. IGF-1 LR3 and MGF work the opposite way, they are growth factors that press the accelerator, directly signaling muscle to grow. Both sound great on paper. But the proof is not there. The only member ever tested in real human trials, ACE-031, was halted for safety. The growth factors have never been trialed for muscle in people and carry a genuine cancer caution, because a signal that tells cells to grow does not only talk to muscle. So the useful thing we can do is line each one up against what it actually does and the proof it actually has. We do honest, not hype.
Read this first
This is education, not medical advice, and it does not replace your own clinician. None of these four is approved for building muscle. ACE-031 was an investigational drug whose trials were stopped; Follistatin, IGF-1 LR3, and MGF are research compounds with essentially no human efficacy data for this use. All are banned in tested sport. Any dose named here is an example for discussion, never a prescription.
90-second self-check
This flags the real hard stops, and if you are clear, points toward the compound that matches your goal. It is education, not a diagnosis or a recommendation to use anything.
Answer honestly. Nothing is stored, and no one sees it but you.
First, the hard stops. Do any of these apply to you? (tap all that are true)
What are you actually weighing this class for?
Any of these in your picture? (tap all that apply)
Is the real muscle-building foundation in place? (tap all that apply)
This reflection is education only, not a diagnosis or a recommendation to use any compound. Talk to a licensed provider about your own history and goals.
The basics
Your body actively limits its own muscle. A protein called myostatin is the brake: animals born without it (and a handful of rare humans) grow enormous, dense muscle. That single fact is the seed of this whole class. Two of these peptides release that brake; the other two skip it and push a growth signal directly:
| Compound | How it works | Studied for | Evidence level | Route |
|---|---|---|---|---|
| ACE-031 | Brake release: decoy soaks up myostatin + activins | Muscular dystrophy, sarcopenia, cachexia | Real human trials, then HALTED for safety | SubQ |
| Follistatin | Brake release: neutralizes myostatin + activins | Muscle-wasting disease (via gene therapy) | Strong via gene therapy; injectable unproven | SubQ |
| IGF-1 LR3 | Accelerator: long-acting IGF-1, direct growth | Muscle growth, recovery (research) | No human muscle trials; cancer + low-sugar risk | SubQ |
| MGF (IGF-1Ec) | Accelerator: local IGF-1 splice, satellite cells | Local muscle repair (research) | No controlled human trials of the injected form | Local IM |
A note on the neighbors: these are NOT growth hormone or its releasers. If you are comparing muscle tools, our GH secretagogue guide and the HGH guide cover that separate class, which drives IGF-1 indirectly through your own liver rather than injecting a growth signal directly.
The honest half-truth you will hear
"They let you break past your genetic limit." Two problems. First, releasing the myostatin brake reliably adds muscle SIZE, but human trials repeatedly failed to turn that size into real STRENGTH or function, and your genetics still set a ceiling. Second, the growth-factor members do not have human muscle trials at all, and "tell every cell to grow" is exactly why the cancer caution is real. Impressive mechanism, thin and cautionary proof.
The part the marketing flattens
They get sold as if the science were settled. It is not. Here is an honest read of how much real human evidence sits behind each. Longer bars mean deeper human data, not "works better," and even the longest one ends in a halted trial.
Depth of human evidence, by compound
ACE-031 is the only one with real human trials, and they were stopped for safety. The rest are gene therapy or preclinical.
ACE-031: Campbell 2017 (DMD trial stopped for epistaxis and telangiectasias). Follistatin: Mendell 2015 (gene-therapy trial, not the injectable peptide). IGF-1 LR3 and MGF: animal and cell data only for muscle. Full citations below.
Read the shape honestly. The one member with real human trials, ACE-031, was halted over bleeding side effects, not a lack of muscle effect. Follistatin's impressive results are gene therapy delivered into the muscle, a different thing from the vial people inject. And the two growth factors have never been tested for building muscle in people. If you are drawn to this class, you are betting on mechanism, not results.
Under the hood
Follistatin and ACE-031 mop up myostatin, the protein your body uses to cap muscle growth. Take the brake off and the muscle-building pathway runs more freely. You are removing a limit, not adding fuel.
IGF-1 LR3 and MGF are growth signals. They switch on muscle protein synthesis and wake up satellite cells (the repair crew). This is pressing the gas directly, which is more potent and less selective.
A brake release has a ceiling (your genes still set the limit) and touches other tissues, ACE-031's off-target effect on blood vessels is what halted its trial. An accelerator that says "grow" to every cell is exactly why IGF-1 LR3 and MGF carry a cancer caution. Neither route is free muscle.
That is the class in one idea: two very different ways to push on muscle, each with a real, mechanism-based catch. Understanding which lever a compound pulls tells you what it can do and, more importantly, where its risk lives.
The four, with honest pros and cons
Same goal, very different levels of proof. Tags show the standing: clinical, gene-therapy, or preclinical.
An engineered decoy receptor that soaks up myostatin and related growth-limiters. The only member with real human trials, and the only one whose safety problem we can actually see.
Honest read: the most-studied member, and its own trials are the clearest warning in this class: mass went up, function did not, and safety stopped it. Given by injection.
A natural myostatin neutralizer. The eye-popping muscle results come from gene therapy delivered into muscle, which is a very different thing from the injectable peptide sold online.
Honest read: the mechanism is a ten; the injectable people actually buy is an open question with almost no human data. Do not confuse the gene therapy for the vial. Given by injection.
A long-acting, engineered version of the growth factor IGF-1 that presses the accelerator directly. The most potent-sounding and, honestly, the riskiest of the four.
Honest read: loud on paper, unproven and high-risk in practice. The cancer and low-blood-sugar cautions are the headline, not the muscle. Given by injection.
A local "mechano-growth" splice of IGF-1 that muscle releases in a brief pulse after hard training, studied for kick-starting repair. Interesting biology, barely any human product data.
Honest read: a small local nudge on top of training at best, and unproven in people. The training itself is doing most of the work. Given by local injection.
The line that matters most
The single most important idea in this class is the gap between size and function. Releasing the myostatin brake reliably makes muscles bigger, that part is real. But when researchers measured whether that extra size made people actually stronger or more mobile, the benefit kept failing to show up. A larger muscle that is not proportionally stronger is a cosmetic result with real risk attached, not a performance breakthrough. And that is the member with the BEST data. The growth factors skip human testing entirely.
Two things to hold onto
First, the only in-class human program (ACE-031) was stopped for safety, not for lack of muscle effect, that tells you the risk is real and specific. Second, the two accelerator peptides (IGF-1 LR3, MGF) are growth signals, so a cancer history is a genuine stop, not a footnote. This is a class where the mechanism is genuinely exciting and the honest human evidence is genuinely thin. Hold both truths at once.
The most important section here
Each of these carries a specific, mechanism-based risk. A few situations are genuinely off-limits or need a provider.
This is the sharpest line, and it is strongest for the growth factors, IGF-1 LR3 and MGF. They are signals that tell cells to grow and resist dying, and that is precisely the wrong message anywhere a malignancy exists or might. This is a mechanistic concern rather than a documented event, but it is a firm reason to stop and involve an oncologist, never to self-experiment.
None of these has human safety data in pregnancy or breastfeeding, and Follistatin also lowers reproductive hormones (FSH), which matters if you are trying to conceive. Clear all of this first.
IGF-1 LR3 cross-reacts with the insulin receptor and can drop blood sugar sharply, with a long tail that makes a low linger for hours. Never inject it fasted, never stack it with insulin or glucose-lowering drugs, and keep fast-acting sugar on hand. Diabetes makes this a provider-only conversation.
The exact thing that halted ACE-031's trial was off-target effects on blood vessels: nosebleeds, spider veins, and gum bleeding. A bleeding disorder or a blood thinner turns that from a nuisance into a real risk. This is a specific, documented caution, not a theoretical one.
None of these is approved for building muscle, purity and sourcing are unregulated, and long-term safety is unknown. All are banned by the World Anti-Doping Agency (growth factors and gene doping), so they are strictly off-limits for any drug-tested athlete.
The one rule under all of it
If you have any cancer history, the growth factors here are not a self-directed project, clear it with an oncologist first. Otherwise, be honest that the human proof is thin, respect the specific risk each one carries, and build the foundation below first, because for actual muscle it does far more than any of these.
Put it together
First question
Second question
The move most people skip
Ask whether the goal is real size, real strength, or just the feeling of doing something extra. These add risk far faster than they add proven muscle, and the honest answer for almost everyone is that training, protein, sleep, and patience will out-build any of them. Match the tool to a real, honest need. Matching beats maxing.
The foundation under everything
Here is the part no muscle peptide wants you to hear: the things that reliably build muscle are free, proven, and boring, and they dwarf everything on this list. These peptides, at best, nudge on top of a foundation. Without it, there is nothing to nudge.
Lifting with steadily increasing challenge is the actual signal that builds muscle. Nothing here replaces it; the growth factors are literally trying to imitate a fraction of what a hard set already does. Train hard and consistently first.
Muscle is built from protein, and you cannot grow in a deep deficit. Roughly 1.6 to 2.2 grams of protein per kilogram of bodyweight, plus enough total food, does more for muscle than any compound in this class. This is the real lever.
Muscle is built during recovery, not during the workout. Short or broken sleep blunts growth and strength directly. No peptide compensates for chronic under-recovery. Protect it.
Real muscle takes years, and your genetics set a ceiling that no brake-release fully overrides. Chasing a shortcut usually trades a small, unproven bump for a real risk. The slow way is the one that actually works.
Cutting through the noise
The genuinely evidence-backed way to build muscle. This does more than every compound on this page combined. Boring, and it works.
The one cheap, deeply proven, safe supplement that reliably supports muscle and strength. If you want to add something with real evidence, it is this, not a peptide.
No human muscle trials, mostly community anecdote, and real (cancer, low-sugar, hormonal) cautions. Curiosity at your own risk, not confidence.
The exact situations where these compounds' specific mechanisms push the wrong way. This is a specialist decision, never a self-directed one.
Turn this into action
Have I honestly ruled out the hard stops: active or recent cancer, and pregnancy?
Am I actually chasing strength and function, or just size, and do I know these often add the first without the second?
Is my training, protein, and sleep genuinely dialed in, so there is even something for a peptide to add to?
If I take a blood thinner or have diabetes, have I accounted for the specific risk (bleeding, low blood sugar)?
Am I clear that the human proof here is thin to nonexistent, and is a provider genuinely involved?
Bring these to your visit
Given my history, especially any cancer, is any of these growth-factor or myostatin peptides safe for me to consider?
If I take insulin or a glucose-lowering drug, how dangerous is the blood-sugar drop from IGF-1 LR3?
If I am on a blood thinner, does ACE-031's bleeding effect rule it out for me?
Given how thin the human evidence is, what realistic result should I even expect, and when would we call it and stop?
A few situations are not "go slower," they are "stop and be seen."
A mild injection-site reaction settles. A low-blood-sugar episode, unusual bleeding, or an allergic reaction do not wait. When in doubt, be seen.
The BlessUp take
The idea here is genuinely seductive: your body caps its own muscle with a brake called myostatin, and these peptides either release that brake or press the accelerator directly. The biology is real and, in the lab, dramatic. But the honest human story is a long way behind the hype. Releasing the brake reliably adds SIZE, and then repeatedly fails to add real STRENGTH. The one member ever tested in people, ACE-031, was stopped over bleeding side effects. And the two growth factors that sound the most powerful, IGF-1 LR3 and MGF, have never been trialed for muscle in humans and carry a real cancer caution, because a signal that shouts "grow" does not only reach your biceps. So do not confuse an exciting mechanism for a proven result, and do not confuse a gene-therapy headline for the vial in your fridge. For actual muscle, the boring foundation, hard progressive training, enough protein, real sleep, and years of patience, out-builds every one of these, at zero risk. If you still have a real reason to explore this class, go in knowing the proof is thin, respect the specific danger each one carries, and do it with a provider. That is not the timid move. It is the one that respects both how the body grows and how little we have actually proven.
The evidence
Retrieved from PubMed. ACE-031 carries the class's real human evidence (in a trial that was halted for safety); Follistatin's muscle data is gene therapy, not the injectable peptide; and myostatin-pathway blockade broadly has shown mass gains without reliable functional benefit.
Citations retrieved from PubMed. ACE-031's own trial is the clearest in-class caution: mass gains, no clear function, halted for safety. Follistatin's muscle results are gene therapy, a fundamentally different intervention from the injectable peptide. IGF-1 LR3 and MGF have animal and cell data for muscle but no controlled human efficacy trials, and as growth factors carry a mechanism-based cancer caution. This report is an honest educational map of the class, not a dosing sheet or a recommendation to use any compound.