Yesterday, I promised to deliver the goods on BioLongevity Labs’ newest project for permanent gains in skeletal muscle mass: Recombinant Follistatin.

A molecule once abandoned has been fully resurrected due to breakthroughs in our understanding of the biochemical mechanisms that allowed it to show promise.

And like I mentioned in the prior article about Klotho, there is untapped synergy between it and Recombinant Follistatin when they are used together.

So without further ado, let’s dive into Part 2!

Special credit goes to BioLongevity Labs’ Chief Science Officer Bryan Moskow and our unnnamed in-house chemist for putting their heads together to create both products and supply us with all the technical information required to write this article.

Recombinant Follistatin (FLGR242): The Latest Evolution In True Skeletal Muscle Mass Gain

Years ago, I wrote about the muscle-building peptide Follistatin 344 because of its growing interest in the bodybuilding community as the ultimate anabolic muscle-building agent.

I highly recommend reading this article as it will give you some background for why we decided to pursue modifications that would improve its utility.

To make a long story short,  Follistatin is a glycoprotein (a protein with a sugar side chain attached to its amino acid side chains) known to selectively inhibit follicle-stimulating hormone.

When the FST gene that encodes Follistatin undergoes alternative gene splicing, you get two highly similar proteins (“isoforms”), one of them being Follistatin 344.

The “344” simply refers to the total number of amino acids it has.

Follistatin 344’s main claim to fame is the inhibition of myostatin, also known in the clinical literature as growth differentiation factor 8 (GDF8).

Myostatin, discovered back in 1997, is a “master negative regulator of skeletal muscle growth during postnatal development and skeletal muscle mass in adulthood” (Source).

So what you have in effect is:

• The blocking of signalling cascades that would typically hinder the development of muscle fibers
• Increasing fiber size, rather than fiber number, to increase muscle mass
• The promotion of satellite cell activation during muscle regeneration protocols

Myostatin levels generally increase with age and is also associated with worsening muscular strength in aging adults, an unavoidable reality of human and mammalian physiology.

Likewise, Follistatin levels concurrently decrease with age, although some evidence suggests levels of myostatin and follistatin with age do not increase/decrease linearly:

(Source)

A classic example of myostatin inhibition in action is the Belgian Blue Cow, the unusually muscular cow with a 25-30% increase in muscle mass compared to normal cattle, due to lacking the myostatin gene (“myostatin null”) that would otherwise hinder muscle growth.

Notably, mice that are myostatin null will grow muscles that are 200-300% heavier compared to the muscles in mice without the same mutation in the myostatin gene, without a corresponding increase in fat (i.e. they have reduced adiposity).

Myostatin inhibition is not without its faults and we will investigate the reasons.

First, it is well-established in the literature, both clinically and preclinically, myostatin inhibition does lead to muscle mass increases but not a proportionate increase in muscle quality (i.e. the ability to generate force for a given amount of muscle mass).

In other words, muscle mass is increased but not the power and function of the muscle.

There was also the issue mice have 3x higher repression of myostatin and 10x the circulating myostatin levels compared to humans.

This proves the successes in preclinical studies with mice do not translate well to humans.

Second, myostatin inhibitors don’t just touch myostatin itself; they also interact with GDF11, activins, and bone morphogenic proteins (BMPs).

This can lead to bone weakness and unwanted vascular effects.

This is why we created Follistatin (FLGR242), a fragmented and modified version of Follistatin 344.

We took Follistatin 344 and fused it with an albumin-binding construct that uses a hydrophilic glycine-serine linker to achieve high-affinity binding to serum albumin.

Yes, the same proprietary 29-amino acid long albumin binding construct (GGSGGSGGSGGRLIEDICLPRWGCLWEDD) used in Klotho is used here to extend the half-life of Follistatin-344 from ~1-2 hours to 19 days.

More specifically, our base was a variation of Follistatin (FS I-I) that still retains its muscle-building properties while hardly affecting activin activity.

We also managed to offset the binding to heparin that Follistatin demonstrates.

This is a fancy way of saying our Follistatin doesn’t break down in the body as easily as the previous version and has an even more pronounced effect on myostatin than activin.

This generates the following characteristics for this peptide:

• Technology: Follistatin 344 plus the albumin-binding peptide fusion (GGSGGSGGSGGRLIEDICLPRWGCLWEDD linker)
• Molecular weight: ~40 kDa
• Binding affinity to serum albumin: <20 nM
• Serum half-life: 19 days 

Our product is an incredible compound  which stimulates muscle growth without affecting other cellular systems or organs.

Dosing Recombinant Follistatin For Best Results

When it comes to injecting Recombinant Follistatin (FGLR242), you have three options:

1. 5mg injected SUBCUTANEOUSLY in the abdominal region once every two weeks (normal use)
2. 2.5mg injected SUBCUTANEOUSLY in the abdominal region once every week (normal use)
3. 5mg injected SUBCUTANEOUSLY in the abdominal region once a week (advanced users seeking maximum hypertrophy)

(NOTE: 31/32 gauge insulin needles will work better than 28/29 gauge insulin needles to reduce the severity and duration of potential swelling, water retention and post-injection pain)

Both approaches will work for adding skeletal muscle mass and/or preventing skeletal muscle loss, and no special adjustments are required for taking it with/without food or around your training sessions.

You’re spacing out the doses this way due to the presence of the albumin binder.

I would say two weeks is about the maximum you would want to go between doses, as injecting once a month will lead to more pronounced peaks and valleys.

And similarly to Klotho,  you want to be within a certain range of Follistatin (~3-4mg to offset the myostatin inhibition).

There’s no need to cycle on-and-off Recombinant Follistatin, but a 3-4 month break will lead to myostatin buildup which will likely have some effect on muscle degradation.

Realistically speaking, you won’t notice much for the first 2-3 weeks, but then you will see more vascularity, better pumps, improved strength gains, and the desired increase in muscle tissue.

(Again, assuming training and nutrition are on point)

But notice how I put “subcutaneously” in all capital letters?

That was not an accident and I’m about to tell you why…

DO NOT INJECT RECOMBINANT FOLLISTATIN INTRAMUSCULARLY UNDER ANY CIRCUMSTANCES!

This product is not like Follistatin 344 and its variants, which require direct injection into the target muscle for localized muscle growth.

If you do this, the albumin will expand once the Recombinant Follistatin is inside and you especially do not want this happening inside muscle tissue.

It will be extremely painful to have something expanding in your muscle tissue, especially around any areas with nerves.

You’ll also notice our recommendation to inject subcutaneously differs greatly from past follistatin-based therapies like ACE-083, which were injected intramuscularly into specific parts of a muscle instead of systemically.

(This could also possibly be due to a limitation of technique application, although ACE-083 was discontinued from clinical investigation in July 2022 because although muscle volume increases were seen, there was a lack of functional improvements and patient-reported outcomes)

The Ultimate Recombinant Follistatin with Klotho Stack

If you were going to use both agents in a stack to maximize results, here is what I would recomomend:

• 5mg of Recombinant Follistatin injected weekly (Double the recommended dose)
• 10mcg of Klotho injected every other week
• Therapeutic Testosterone along with Growth Hormone and or GH Agonist Peptides (Tesa/Ipa/CJC)
• 0.1-0.25mg of Retatrutide injected every other day
• 250mcg of Recombinant TB-500 injected every day (For now just use TB-500 until we release our recombinant formulation)

Nothing in the global drug pipeline is going to beat this for the next 2-3 years.

I would highly recommend this stack for any GLP-1 peptide user, and specifically recommend Retatrutide due to its improved nutrient partioning and insulin signaling effects.

Even though GLP-1 peptides themselves do not DIRECTLY cause muscle loss, many people will suffer muscle tissue breakdown as a result of factors such as hormone deficiency, inadequate protein intake and a lack of bone-bearing resistance training.

Because Recombinant Follistatin significantly increases skeletal muscle growth (and far more effectively than other current forms of Follistatin), it will help people retain muscle mass during periods of low calorie intake.

Especially given the loss of muscle tissue leads to a decrease in basal metabolic rate and consequently fewer calories burned at rest.

This makes it much more difficult to lose body fat while avoiding muscle loss at the same time.

There is also synergy with the addition of Klotho because of its effects on stem muscle cell regeneration and overcome muscle fibrosis.

And due to Klotho’s cardioprotective effects, you would offset any potentially negative effects on the cardiovascular system.

Realistic Expectations For Muscle Gain On Recombinant Follistatin

Will you become the next 300-lb mass monster who takes 1st place at Mr. Olympia within a year of using Recombinant Follistatin?

Absolutely not.

But when it’s used by biohackers, performance athletes and every day gym goers, FLGR242 will lead to measurable gains in skeletal muscle mass unlike anything else available.

So let’s lay down some reasonable outcomes one can expect to see within a set period of time.

Within 12-16 weeks of using Recombinant Follistatin alongside hormonal optimization, proper training, nutrition, rest and recovery, I would say roughly .5 to 1 pound of true skeletal mass per week can be attained.

(Sorry boys and girls, but Recombinant Follistatin doesn’t override the necessity of a caloric surplus and training to positive muscle failure, and it definitely does not break the laws of thermodynamics)

I’ve seen some low-responders put on 0.5-lbs of muscle a week and some high-responders put on up to 1.5 lbs of muscle tissue a week (genetics and androgen receptor sensitivity are still a factor, you know).

This is referring to real solid skeletal muscle you can keep on your frame, not water weight.

You’ll personally start to notice some of the performance-related effects around the 3rd day or so following the day of your first injection.

“But how much do I keep if I stop using Recombinant Follistatin?”

It depends entirely on your age, DNA, health status (are you hormonally optimized), training history, current body composition, and a wide variety of factors.

Being older is a big factor as your ability to maintain muscle gradually declines with age.

Building permanent muscle tissue takes TIME and Recombinant Follistatin can’t help you very much if  you don’t consistently do all the things.

In my professional opinion I would estimate you can keep 75-80% of the gains you make from an entire year of using Follistatin productively.

The results I AM about to share of myself is picture-proof this stuff works exactly as intended even after just 7 weeks of usage.

IAM the biggest and leanest I’ve ever been in my life at nearly 55 years young!

(NOTE: you should be aware Follistatin 344 is a banned WADA substance… it does work, just not nearly as well as what BioLongevity Labs will be offering soon)

Jay Campbell’s Experiment With Recombinant Follistatin (So Far)

Speaking from my N-of-1 experience, I was using Recombinant Follistatin during a period in my life where my training and diet were the furthest thing away from being on point.

Extensive traveling combined with inconsistent sleep and insufficient access to proper gyms and good food meant I wasn’t doing things the usual Jay Campbell way.

Nevertheless, here are my quick observations from 8 weeks of use

• Training intensity and post-gym pumps are INSANE, I feel like I have enough strength to train twice a day.
• Some days, I walk around veiny and pumped without training, almost as if I am glycogen supercompensated… even a mere inadvertent muscle contraction creates a pump!
• Getting leaner in areas of my body where I am not usually so, which leads me to believe there may be a fat-burning effect to Follistatin (don’t count on it too heavily as I only found one in vivo study talking about the possibility of Follistatin increasing energy expenditure)
• My arms are very grainy and separated.
• Any abdominal swelling and post-injection pain is moderate at worst, but never severe

If I really wanted to get down and geeky with the data collection, I would have gotten my blood work done for myostatin measurements prior to starting Recombinant Follistatin, followed by another measurement after 8 weeks of use while keeping all other variables around diet, training and sleep the same.

But you probably want to SEE the results and not hear about them.

So here are some photos to show you I AM serious about these results…

October 30th, looking at my new-found arm definition:

November 18th, weighing in at a peak and lean 219.5lbs:

Friday November 21st 221.9 pounds.

Answering Commonly Asked Questions About Recombinant Follistatin

Q: How do you foresee Recombinant Follistatin being used by people who are also on a GLP-1 peptide like Semaglutide or Tirzepatide? 

A: One of the most common outcomes you see with GLP-1 peptide users is nutrient suppression.

The appetite suppression kicks in and they don’t want to eat as much food anymore, except in doing so they are not getting the nutrients their body requires.

That unfortunately includes the minimal amount of protein required to combat muscle loss (1 gram per pound of LEAN body mass, and higher than that for leaner people).=

You also have the common statistic of 50% of GLP-1 users dropping out within their first year of treatment (nearly 20% within the first 3 months), and an estimated quarter of them never reach their maximal maintenance dose.

(Obviously I do not agree with this as people should be micro-dosing GLP-1 peptides instead of following the official dosing recommendations, much more will be coming in my new book Metabolic Awakening with GLP-1 Peptides)

The reality is the many millions of people using GLP-1 peptides want to not only build muscle, but also preserve it, especially if they are older.

They want to lose their fat without also losing muscle in order to have a much lower chance of rebound weight gain after they stop using a GLP-1 peptide.

Recombinant Follistatin can dramatically help this growing market of ~35 million Americans by building muscle while losing fat they create the type of body which has sufficient biochemical and physiological resilience to maintain their new body composition for years.

Q: What side effects should I know about when using Recombinant Follistatin?

A: Normally, using a myostatin inhibitor would mean you would have to worry about side effects.

But since there’s the of lack of interaction with activin and GDF11, we only have to worry about pure myostatin inhibition.

(NOTE: Although to my knowledge, there shouldn’t be any side effect that comes with pure myostatin inhibition without touching other molecules and receptors..

We modified Recombinant Follistatin to downsize any risks, which also includes upregulating the positive effects.

This is in addition to the fact our version is shown to have a corresponding increase in muscle size and strength, which is not seen in older-generation myostatin inhibitors.

For people older than 50, you have a unique combination not available anywhere else but  highly effective and equally safe.

Where To Buy Recombinant Follistatin

 

Recombinant Follistatin is perfect for any GLP-1 user who wants to preserve skeletal muscle mass (especially if you aren’t using therapeutic testosterone at the same time), and for any older woman who is fearful of osteoporosis and sarcopenia.

Due to the ongoing chaos within the world of Trump Tariffs, Recombinant Follistatin is currently on wait list only at BioLongevity Labs. 

As of the launch of this article,  it will be available for presale within 36 hours alongside Klotho.

Once they arrive in our warehouse, you’ll be one of the first ones to be notified as long as you’re subscribed to my email list (along with the individual waitlists for both compounds).

And like I said in the prior Klotho article, you will be able to buy either one in isolation or both of them at once.

And there will be a massive incentive for anybody who buys a year’s supply of them upfront.

However, let me be the first to warn you about your future purchase…

When it comes to ANY peptide, quality makes all the difference.

Just as you wouldn’t put low-grade fuel in a precision engine, you sure wouldn’t put anything less than the purest peptides in your body.

That’s why source quality and manufacturing standards matter.

I’ve personally vetted dozens of peptide suppliers, and I can tell you this without hesitation:

BioLongevity Labs sets the benchmark for authentic USA manufactured research peptides and small molecules along with our brand new USA manufactured Khavinson bioregulators.

Each product is made with a ruthless focus on stringent third-party testing and top-notch customer service.

They consistently deliver the highest quality products, trusted by professionals for both personal and clinical use.

Whether you’re looking to elevate your performance or integrate these products into research applications, BioLongevity Labs is a reliable source you can count on.

👉 Click here to place your online order at BioLongevity Labs👈

Use code JayC to get 15% off your order!

I also invite you to join me and other like-minded biohackers in The Fully Optimized Health Private Membership Group.

This is where we dive deep into using peptides to optimize health, especially for those in their 30s and beyond.

We’re also talking about cutting-edge biohacking and the latest and greatest in elite health optimization strategies.