Performance Peptides: The Complete Guide to Muscle, Recovery & Athletic Enhancement

⚠️ Medical Disclaimer: This article is for educational purposes only. It is not medical advice. Peptides can have serious side effects and drug interactions. Always talk to a doctor before using any peptide. Never self-diagnose or self-treat based on internet research. Many of the peptides discussed here are banned in competitive sports.

---

Key Takeaways

• Performance peptides help with muscle growth, fat loss, recovery, and endurance — mostly by boosting your body's own growth hormone (GH) production.
• Growth hormone releasing peptides (GHRPs) like GHRP-6, GHRP-2, hexarelin, and ipamorelin signal your brain to release more growth hormone naturally.
• IGF-1 LR3 is a modified version of insulin-like growth factor that directly promotes muscle cell growth and stays active much longer than natural IGF-1.
• Follistatin blocks myostatin, the protein that limits how much muscle you can build. Less myostatin means more potential for muscle growth.
• AOD-9604 is a fragment of human growth hormone designed specifically for fat loss — without the side effects of full GH therapy.
• MK-677 (Ibutamoren) isn't technically a peptide, but it mimics ghrelin and boosts growth hormone levels orally — no injections needed.
• Most of these peptides are banned by WADA and other sports organizations. They are also not FDA-approved for performance enhancement.
• Quality and sourcing matter enormously. The peptide market is largely unregulated, and contaminated or fake products are common.

---

What Are Performance Peptides?

Performance peptides are a group of compounds that people use to build muscle, burn fat, recover faster, and improve physical performance. Most of them work by tapping into your body's growth hormone (GH) system.

Here's the simple version: your pituitary gland (a pea-sized gland at the base of your brain) makes growth hormone. GH does a lot of things — it helps build muscle, burn fat, strengthen bones, and repair tissues. When you're young, you produce a lot of it. As you age, production drops.

Performance peptides either:

1. Tell your brain to make more GH (secretagogues like GHRPs and MK-677)
2. Act directly on muscle and fat tissue (like IGF-1 LR3 and AOD-9604)
3. Remove natural limits on muscle growth (like follistatin)

The appeal is obvious. Instead of injecting synthetic growth hormone directly (which is expensive, tightly regulated, and comes with serious side effects), these peptides work with your body's own systems. At least, that's the theory.

Let's go through each one.

---

Growth Hormone Releasing Peptides (GHRPs)

GHRPs are the backbone of the performance peptide world. They've been around since the 1980s and are the most studied group of performance-enhancing peptides.

How GHRPs Work

Your body controls growth hormone release through two signals:

• GHRH (Growth Hormone-Releasing Hormone) — the "go" signal. It tells the pituitary to release GH.
• Somatostatin — the "stop" signal. It tells the pituitary to hold back.

GHRPs work by mimicking a third hormone called ghrelin — the same hormone that makes you hungry. Ghrelin binds to receptors called GHS-R (growth hormone secretagogue receptors) in the pituitary and hypothalamus. When these receptors are activated, they amplify the GH release signal and reduce the somatostatin brake.

The result: your body releases more of its own growth hormone in bigger, more frequent pulses.

This is fundamentally different from injecting synthetic GH. When you inject GH directly, you bypass your body's feedback system. Your pituitary senses the extra GH floating around and makes even less on its own. Over time, this can cause dependency. GHRPs avoid this problem because they work through your body's natural regulation. Your pituitary is still in charge — it's just getting a louder signal.

GHRP-6

GHRP-6 was one of the first growth hormone releasing peptides developed. It was created in the 1980s and has been studied extensively in both animals and humans.

What it does:

• Increases growth hormone release by 3 to 6 times above baseline
• Strongly stimulates appetite (this is a major effect, not a minor side effect)
• May increase cortisol and prolactin at higher doses
• Promotes fat loss and lean mass gains when combined with exercise

How it's used: Typically injected subcutaneously (under the skin) at doses of 100–300 mcg, 2–3 times per day. Usually taken on an empty stomach because food (especially fats and carbs) can blunt the GH response.

The appetite effect: GHRP-6 is famous for making people extremely hungry within 20 minutes of injection. This happens because it activates the same ghrelin receptors that control hunger. For people trying to bulk up and gain weight, this is actually helpful. For people trying to lose fat, it's a problem.

Evidence: Multiple human studies confirm that GHRP-6 significantly increases growth hormone, IGF-1, and ACTH levels. A 1997 study published in the Journal of Clinical Endocrinology & Metabolism showed that GHRP-6 produced reliable GH pulses in both young and older adults. However, long-term safety data is limited, and it is not FDA-approved for any indication.

GHRP-2

GHRP-2 is considered the more refined version of GHRP-6. It was developed later and addresses some of GHRP-6's shortcomings.

What it does:

• Produces the strongest GH release of any GHRP — roughly 5 to 8 times above baseline
• Less appetite stimulation than GHRP-6 (still some, but more manageable)
• May increase cortisol and prolactin, though generally less than GHRP-6
• Better overall GH release per microgram than its predecessor

How it's used: Similar to GHRP-6 — subcutaneous injection at 100–300 mcg, 2–3 times daily. Same empty stomach protocol.

Why people choose it over GHRP-6: GHRP-2 gives you more growth hormone with less hunger. If your goal is performance and recovery rather than weight gain, GHRP-2 is usually the better choice.

Evidence: Clinical studies in humans show robust GH release. A study in Hormone Research demonstrated that GHRP-2 was effective even in elderly subjects whose natural GH production had declined significantly. It has been studied as a potential treatment for growth hormone deficiency, though it never received FDA approval.

Hexarelin

Hexarelin is the most potent GHRP ever developed. It produces the single largest GH spike of any compound in this class.

What it does:

• Produces massive growth hormone release — up to 10 times above baseline in some studies
• Has cardiovascular protective effects independent of GH release
• Strongly raises cortisol and prolactin (more than GHRP-2 or GHRP-6)
• Leads to rapid desensitization — your body stops responding as strongly after 4–8 weeks

The desensitization problem: This is the big issue with hexarelin. Unlike other GHRPs, your body builds tolerance to hexarelin relatively quickly. After about a month of daily use, the GH response can drop by 50% or more. This makes it impractical for long-term use. Most protocols recommend cycling it — using it for 4 weeks, taking a break, then starting again.

Cardiovascular effects: Interestingly, hexarelin appears to protect the heart through mechanisms that have nothing to do with growth hormone. Research published in the European Journal of Pharmacology showed that hexarelin reduced cardiac fibrosis and improved heart function in animal models of heart failure. This has led some researchers to investigate it as a potential heart drug, separate from its GH-releasing properties.

Evidence: Well-studied in humans for GH release. The cardiovascular benefits are mostly from animal studies. Not FDA-approved.

Ipamorelin

Ipamorelin is often called the "cleanest" GHRP. It's the most popular choice for people new to performance peptides.

What it does:

• Increases growth hormone release by 3 to 5 times above baseline
• Does NOT significantly affect cortisol, prolactin, or ACTH
• Does NOT stimulate appetite like GHRP-6
• Slower, more sustained GH release compared to hexarelin's sharp spike
• Very low incidence of side effects

Why it's so popular: Ipamorelin is selective. It hits the growth hormone receptors without triggering the side-effect pathways that other GHRPs activate. No cortisol spikes means no increased stress hormones. No prolactin increase means no concerns about the hormonal imbalances that higher prolactin can cause. No hunger surge means it works for both bulking and cutting.

How it's used: 200–300 mcg subcutaneously, typically 2–3 times per day. Often combined with CJC-1295 (a GHRH analog) for a synergistic effect — ipamorelin amplifies the release, and CJC-1295 extends the duration.

The ipamorelin + CJC-1295 stack: This is the most widely used peptide combination in the performance space. CJC-1295 provides the baseline signal to release GH, and ipamorelin kicks the release into a higher gear. Studies show that combining a GHRH analog with a GHRP produces a much bigger GH pulse than either one alone — often 10–15 times above baseline.

Evidence: Several clinical studies confirm its GH-releasing effects and favorable side-effect profile. A trial published in Growth Hormone & IGF Research found that ipamorelin reliably increased GH levels without affecting other pituitary hormones. Not FDA-approved, but widely regarded as the safest GHRP available.

Comparing the GHRPs

---

IGF-1 LR3 (Long Arginine 3-IGF-1)

If GHRPs work by telling your body to make more growth hormone, IGF-1 LR3 skips that step entirely. It goes directly to the tissues where growth happens.

How IGF-1 Works in Your Body

Here's the normal chain of events:

1. Your pituitary releases growth hormone (GH)
2. GH travels to your liver
3. Your liver converts GH into IGF-1 (Insulin-like Growth Factor 1)
4. IGF-1 travels through your blood and tells muscles, bones, and other tissues to grow

IGF-1 is the actual growth signal. Growth hormone is just the messenger that triggers it. When researchers measure the long-term effects of GH therapy, they're really measuring the effects of the IGF-1 it produces.

What Makes LR3 Different

Natural IGF-1 has a problem: it gets grabbed by binding proteins in your blood almost immediately. These binding proteins regulate how much IGF-1 is available to your tissues. As a result, natural IGF-1 only stays active for about 12–15 minutes.

IGF-1 LR3 is a modified version that's been engineered to dodge those binding proteins. The "LR3" stands for "Long Arginine 3" — it has an extra 13 amino acids and one amino acid swap. These changes mean:

• It stays active for 20–30 hours instead of 12–15 minutes
• It doesn't get trapped by binding proteins, so more of it reaches your muscles
• It's roughly 2–3 times more potent than natural IGF-1

What IGF-1 LR3 Does

Muscle growth: IGF-1 LR3 promotes muscle growth in two ways. First, it causes existing muscle fibers to get bigger (hypertrophy) by increasing protein synthesis. Second — and this is the exciting part — it promotes hyperplasia, the creation of entirely new muscle cells. Most training methods and even anabolic steroids only cause hypertrophy. Hyperplasia is much rarer and could theoretically raise your genetic ceiling for muscle growth.

Fat loss: IGF-1 LR3 encourages your body to use fat for energy instead of glucose. This effect is modest compared to its muscle-building properties, but it contributes to improved body composition.

Recovery: By accelerating protein synthesis and cellular repair, IGF-1 LR3 can significantly speed up recovery from training and injury. This means more frequent, harder training sessions.

Anti-catabolic effects: IGF-1 LR3 helps prevent muscle breakdown during caloric restriction. This makes it potentially useful during cutting phases when you want to lose fat without losing muscle.

Risks and Side Effects

IGF-1 LR3 is one of the more powerful — and more dangerous — performance peptides:

• Hypoglycemia: IGF-1 acts like insulin and can cause blood sugar to drop dangerously low. This is especially risky during fasting or intense exercise.
• Organ growth: Unlike targeted muscle growth, IGF-1 affects all tissues. Prolonged use can cause intestinal growth (distended gut), heart enlargement, and other unwanted organ changes.
• Cancer concerns: IGF-1 promotes cell growth. Period. It doesn't distinguish between healthy cells and cancerous ones. Elevated IGF-1 levels have been linked to increased risk of certain cancers in epidemiological studies.
• Joint pain and swelling: Common at higher doses.
• Gut distension: The "GH gut" or "bubble gut" seen in some bodybuilders is partly attributed to IGF-1-driven growth of intestinal tissues.

Dosing: Typically 20–50 mcg per day injected subcutaneously. Some protocols call for site-specific intramuscular injection into the target muscle group, though evidence that this produces localized growth is debated.

Evidence: IGF-1 (not the LR3 variant) is actually FDA-approved as Mecasermin (brand name Increlex) for children with severe IGF-1 deficiency. IGF-1 LR3 specifically is a research compound with extensive animal data but limited controlled human studies for performance enhancement. Its mechanism is well-understood from decades of endocrinology research.

---

Follistatin

Follistatin takes a completely different approach to muscle growth. Instead of adding a growth signal, it removes a growth limiter.

The Myostatin Brake

Your body has a built-in system that limits how much muscle you can build. The protein responsible for this limit is called myostatin. Myostatin circulates in your blood and tells your muscles: "That's enough. Stop growing."

This makes sense from an evolutionary perspective. Muscle is expensive to maintain — it requires a lot of calories. Your body doesn't want more muscle than it needs for survival. So myostatin acts as a governor on a car engine, capping your maximum muscle mass.

You've probably seen photos of those incredibly muscular cows (Belgian Blue cattle) or super-jacked whippet dogs. These animals have natural mutations that disable their myostatin gene. Without the brake, their muscles grow far beyond normal limits.

How Follistatin Works

Follistatin is a natural protein your body produces. One of its jobs is to bind to myostatin and neutralize it. Think of it as putting a sock over the brake pedal — myostatin is still there, but it can't do its job as effectively.

By increasing follistatin levels beyond what your body normally makes, you can partially suppress myostatin activity. The result is an enhanced ability to build and retain muscle.

Follistatin also:

• Blocks activin, another protein in the same family as myostatin that also limits muscle growth
• Supports reproductive health — it was originally discovered for its role in regulating follicle-stimulating hormone (FSH)
• May improve metabolic health — animal studies suggest follistatin can improve insulin sensitivity and reduce fat mass

Different Forms of Follistatin

There are several variants, and they matter:

• Follistatin 344 (FS-344): The most common form used in the performance space. It's the full-length version that affects multiple tissues. Because it's less specific, it can have broader effects — both wanted and unwanted.
• Follistatin 315 (FS-315): A more targeted form that primarily acts on muscle tissue. It has less effect on reproductive hormones and other systems. Generally considered safer for performance use.
• Follistatin 288 (FS-288): Primarily involved in reproductive function. Not commonly used for muscle growth.

What the Evidence Shows

The myostatin-blocking concept is well-proven:

• Animal studies are dramatic. Mice given follistatin gene therapy showed muscle mass increases of 15–25% and significant strength gains. Similar results have been seen in primates.
• Human gene therapy trials have been conducted for muscular dystrophy, using follistatin gene delivery. A 2015 study published in Molecular Therapy showed improved walking ability in patients with inclusion body myositis (a muscle-wasting disease) after follistatin gene therapy.
• Injectable follistatin for performance enhancement has much less data. The protein is fragile and difficult to produce in stable injectable form. Most "follistatin" sold in the peptide market is of questionable quality and actual content.

Risks and Limitations

• Reproductive effects: FS-344 can suppress follicle-stimulating hormone, potentially affecting fertility. This is less of a concern with FS-315.
• Quality concerns: Follistatin is a large, complex protein that degrades easily. Much of what's sold online may be partially or fully inactive.
• Limited human data for injectable use in performance contexts. The most exciting evidence comes from gene therapy, which is a completely different delivery method.
• Unknown long-term effects of sustained myostatin suppression in healthy adults.

---

AOD-9604

AOD-9604 is the minimalist approach to growth hormone. Instead of using the whole molecule, scientists took just the small piece that handles fat loss and threw away the rest.

What It Is

Human growth hormone is a large protein with 191 amino acids. It does many things: builds muscle, burns fat, grows bones, affects blood sugar, and more. AOD-9604 is a fragment — specifically amino acids 177 through 191, with a tyrosine added to the beginning. That's just 16 amino acids out of the original 191.

This particular fragment retains GH's fat-burning properties but doesn't appear to affect blood sugar, muscle growth, or other systems the way full GH does.

How It Burns Fat

AOD-9604 works on fat cells in two ways:

1. Stimulates lipolysis — it tells fat cells to release their stored fat into the bloodstream so it can be burned for energy
2. Inhibits lipogenesis — it slows down the process of turning food into new fat storage

These are the same mechanisms that full growth hormone uses to promote fat loss, just isolated from all the other effects. The fragment activates the beta-3 adrenergic receptor pathway in fat tissue, which is the same pathway activated by exercise and cold exposure.

What Makes It Attractive

• No effect on blood sugar: Full GH can cause insulin resistance and elevated blood sugar. AOD-9604 does not appear to have this effect in clinical studies.
• No effect on IGF-1 levels: This means fewer concerns about organ growth, cancer risk, and other IGF-1-related side effects.
• No muscle growth effect: This sounds like a disadvantage, but it means AOD-9604 is specifically a fat-loss tool. You're not dealing with unpredictable growth effects.
• Oral bioavailability: Some research suggests AOD-9604 may be effective when taken orally, which would be unusual and convenient for a peptide.

Clinical Evidence

AOD-9604 has an interesting regulatory history:

• In 2004, a Phase 2 clinical trial of 300 obese patients found that AOD-9604 reduced body fat without serious side effects. However, the results were considered "modest" — not enough for pharmaceutical companies to pursue it further.
• The Therapeutic Goods Administration (TGA) in Australia granted it GRAS (Generally Recognized As Safe) status for use as a food ingredient in 2007. This is unusual for a peptide derivative.
• Despite the GRAS status, no regulatory agency has approved AOD-9604 as a drug for fat loss.
• More recently, AOD-9604 has gained attention in the regenerative medicine space for potential joint repair properties. Some practitioners use it in combination with BPC-157 for osteoarthritis and joint pain, though this evidence is still preliminary.

Realistic Expectations

AOD-9604 is not a miracle fat burner. The clinical data suggests modest effects. You should not expect it to replace diet and exercise. People who see the best results typically use it alongside a caloric deficit and regular training. Think of it as a tool that makes your existing fat-loss efforts slightly more effective — not a shortcut that replaces them.

Dosing: Typically 250–300 mcg per day, injected subcutaneously. Some protocols split this into two doses. Usually taken on an empty stomach, first thing in the morning.

---

MK-677 (Ibutamoren)

MK-677 is the odd one out on this list. It's not actually a peptide — it's a small molecule that you swallow as a pill or capsule. But it's always grouped with performance peptides because it does the same thing they do: boost growth hormone.

How It Works

MK-677 mimics ghrelin, the "hunger hormone." When you take MK-677, it binds to ghrelin receptors (GHS-R1a) in the brain, just like natural ghrelin would. This triggers the pituitary gland to release growth hormone.

But MK-677 has a unique advantage: it's orally active and has a long half-life (roughly 24 hours). This means:

• One dose per day is enough (compared to 2–3 injections daily for GHRPs)
• No needles — it's taken by mouth
• Sustained GH elevation — rather than sharp spikes and valleys, MK-677 keeps GH levels elevated throughout the day, more closely mimicking what a young, healthy body does naturally

What It Does

Increases growth hormone: Studies show that MK-677 can increase GH levels by 40–97% depending on the dose and the individual. In older adults, it essentially restores GH levels to what they were in young adulthood.

Raises IGF-1: Because MK-677 increases GH, and GH stimulates IGF-1 production in the liver, IGF-1 levels rise as well. A landmark study published in the Journal of Clinical Endocrinology & Metabolism in 1998 showed that MK-677 increased IGF-1 levels by 40% in elderly subjects over 12 months.

Improves sleep quality: Many users report deeper, more restful sleep. This isn't just anecdotal — MK-677 has been shown to increase Stage 4 (deep) sleep and REM sleep duration. Since GH is primarily released during deep sleep, this creates a positive feedback loop.

Increases appetite: Like GHRP-6, MK-677 activates ghrelin receptors, which makes you hungry. This effect is strong, especially in the first few weeks of use. Some people find it manageable after the initial period. Others find it overwhelming.

Preserves muscle during caloric deficit: A 1998 study gave MK-677 to healthy young adults on a calorie-restricted diet. The MK-677 group maintained their muscle mass and metabolic rate while the placebo group lost both. This makes MK-677 potentially valuable during cutting phases.

The Side Effects You Need to Know

MK-677 is not without problems, and some are serious:

Blood sugar and insulin resistance: This is the biggest concern. MK-677 can elevate fasting blood glucose and reduce insulin sensitivity. For people who are already prediabetic or insulin resistant, this could push them into diabetes territory. A 2-year study in elderly patients found increased fasting glucose levels in the MK-677 group compared to placebo.

Water retention and bloating: Growth hormone causes your body to retain water and sodium. With MK-677's sustained GH elevation, water retention can be significant — some users report gaining 5–10 pounds of water weight in the first few weeks. This is temporary and reversible, but uncomfortable.

Increased appetite: Already mentioned, but worth repeating. Some users find the hunger nearly impossible to control, which can undermine fat loss goals.

Lethargy and brain fog: Some users report feeling sluggish, especially at higher doses. This may be related to the blood sugar effects.

Joint pain and numbness: Tingling or numbness in hands and feet (similar to carpal tunnel syndrome) can occur, likely related to water retention and fluid pressure on nerves.

Potential tumor growth concern: Like any compound that raises IGF-1, there is a theoretical concern about promoting the growth of existing tumors. People with a history of cancer should avoid MK-677.

Dosing

Most studies use 10–25 mg per day taken orally, usually before bed (to align with natural GH release during sleep and to sleep through the worst of the appetite spike). Some users start at 10 mg to assess tolerance before increasing to 25 mg.

Evidence Quality

MK-677 has the strongest clinical evidence of any compound on this list:

• Multiple randomized, placebo-controlled studies in humans
• Studies lasting up to 2 years
• Studied in elderly, young adults, and obese populations
• Well-characterized side-effect profile

Despite all this data, MK-677 has never received FDA approval. Merck developed it in the 1990s and ultimately decided not to pursue it as a drug, likely because the side-effect profile (especially blood sugar issues) made it difficult to justify for long-term use in otherwise healthy people.

---

How These Peptides Compare

---

Stacking: How People Combine Them

In practice, many people don't use just one peptide. They combine — or "stack" — multiple compounds to get synergistic effects. Here are the most common stacks:

The GH Maximizer Stack: CJC-1295 + Ipamorelin

This is the gold standard starter stack. CJC-1295 (a GHRH analog) provides the baseline signal, and ipamorelin amplifies it. Together, they can produce GH release 10–15 times above baseline. This combination is popular because:

• Both have relatively mild side-effect profiles
• They work through complementary mechanisms
• The effects are additive, not redundant

The Body Recomposition Stack: MK-677 + AOD-9604

MK-677 provides sustained GH elevation and muscle preservation, while AOD-9604 targets fat specifically. The idea is to shift your body composition — more muscle, less fat — simultaneously.

The Advanced Muscle Stack: Ipamorelin + IGF-1 LR3

This combines GH-mediated growth with direct IGF-1 stimulation. It's considered more aggressive and carries higher risk, particularly regarding blood sugar management and the growth-promoting effects of elevated IGF-1.

Important note: Stacking peptides increases both the potential benefits and the potential risks. Side effects can compound unpredictably. There is very little clinical research on most peptide combinations. People who stack should work with a knowledgeable healthcare provider and monitor blood work regularly.

---

Legal Status and Sports Regulations

This is important, so pay attention.

WADA and Competitive Sports

The World Anti-Doping Agency (WADA) bans virtually all performance peptides. Their Prohibited List includes:

• All GHRPs (GHRP-6, GHRP-2, hexarelin, ipamorelin)
• All GH secretagogues (including MK-677)
• IGF-1 and all its analogs (including LR3)
• Growth hormone and all its fragments (including AOD-9604)
• Myostatin inhibitors (including follistatin)

If you compete in any sport that follows WADA rules — which includes the Olympics, NCAA, most professional sports leagues, CrossFit Games, and many amateur organizations — using any of these compounds will result in a doping violation. The consequences typically include a multi-year ban from competition.

FDA Regulatory Status

None of these peptides are FDA-approved for performance enhancement or bodybuilding:

• MK-677 was developed by Merck but never submitted for FDA approval
• AOD-9604 has GRAS status in Australia but no drug approval anywhere
• IGF-1 is approved only as Mecasermin (Increlex) for severe pediatric IGF-1 deficiency — not for performance use
• GHRPs have been studied clinically but none are approved drugs in the United States
• Follistatin has been investigated in gene therapy trials but is not approved as an injectable performance supplement

Most of these peptides are sold as "research chemicals" — a legal gray area that allows them to be manufactured and sold, but not marketed for human consumption. Whether buying them for personal use is legal depends on your jurisdiction.

---

Safety Considerations

If you're considering performance peptides, here are the things you need to think about seriously:

Blood Work Is Mandatory

You should get baseline blood work before starting any peptide, and monitor regularly during use. Key markers to track:

• IGF-1 levels — to make sure they're in a healthy range and not excessively elevated
• Fasting glucose and HbA1c — especially with MK-677, GHRPs, or IGF-1 LR3
• Insulin levels — to catch insulin resistance early
• Prolactin — if using GHRP-6, GHRP-2, or hexarelin
• Cortisol — same reason
• Complete metabolic panel and CBC — general health markers

Source Quality Matters More Than You Think

The peptide market is largely unregulated. When you buy a peptide online, you're trusting the vendor to:

• Actually put the right compound in the vial
• Produce it at the right purity (99%+ for injectable compounds)
• Keep it free of bacteria, endotoxins, and heavy metals
• Store and ship it correctly (many peptides degrade in heat)

Independent testing has shown that a significant percentage of peptides sold online are either under-dosed, contaminated, or contain the wrong compound entirely. Always demand third-party Certificates of Analysis (COAs) and buy from vendors with established, verifiable track records.

Start Low, Go Slow

Every peptide in this article has a dose-response relationship: more is not always better, and side effects increase with dose. Start with the lowest effective dose, assess your response, and increase gradually if needed. This is especially important with IGF-1 LR3 (hypoglycemia risk) and MK-677 (blood sugar effects).

Don't Ignore the Basics

No peptide will compensate for poor training, bad nutrition, or inadequate sleep. The people who see the best results from performance peptides are the ones who already have their fundamentals locked in:

• Consistent progressive resistance training
• Adequate protein intake (1.6–2.2 g per kg of body weight)
• 7–9 hours of quality sleep
• Managed stress levels
• Caloric intake aligned with goals (surplus for bulking, deficit for cutting)

Peptides can enhance these fundamentals. They cannot replace them.

---

The Bottom Line

Performance peptides are real compounds with real mechanisms of action, backed by varying levels of evidence. GHRPs like ipamorelin and GHRP-2 are the most well-studied and safest options for boosting growth hormone. MK-677 offers the convenience of oral dosing with strong clinical evidence but comes with notable side effects. IGF-1 LR3 is powerful but risky. Follistatin is theoretically exciting but practically limited by quality and delivery challenges. AOD-9604 is the gentlest option for targeted fat loss.

None of these compounds are magic. None of them are approved for performance use. All of them carry risks. And the unregulated market they're sold in adds an additional layer of uncertainty.

If you choose to explore performance peptides, do it with eyes open: get medical supervision, monitor your blood work, source carefully, and never lose sight of the fact that training, nutrition, and sleep will always be the foundation that everything else is built on.

---

Sources and Further Reading

• Bowers, C.Y. (1998). "Growth Hormone-Releasing Peptide (GHRP)." Cellular and Molecular Life Sciences, 54(12), 1316–1329.
• Nass, R., et al. (2008). "Effects of an Oral Ghrelin Mimetic on Body Composition and Clinical Outcomes in Healthy Older Adults." Annals of Internal Medicine, 149(9), 601–611.
• Murphy, M.G., et al. (1998). "MK-677, an Orally Active Growth Hormone Secretagogue, Reverses Diet-Induced Catabolism." Journal of Clinical Endocrinology & Metabolism, 83(2), 320–325.
• Haidet, A.M., et al. (2008). "Long-term Enhancement of Skeletal Muscle Mass and Strength by Single Gene Administration of Myostatin Inhibitors." Proceedings of the National Academy of Sciences, 105(11), 4318–4322.
• Heffernan, M.A., et al. (2001). "The Effects of Human GH and Its Lipolytic Fragment (AOD9604) on Lipid Metabolism Following Chronic Treatment in Obese Mice and Beta3-AR Knock-Out Mice." Endocrinology, 142(12), 5182–5189.
• Clemmons, D.R. (2007). "Modifying IGF1 Activity: An Approach to Treat Endocrine Disorders, Atherosclerosis and Cancer." Molecular Endocrinology, 21(7), 1414–1424.
• WADA Prohibited List 2026. World Anti-Doping Agency. Available at: https://www.wada-ama.org

---

Last updated: July 2025. This article is reviewed quarterly and updated as new research becomes available.

Peptok is an independent educational resource. We do not sell peptides and have no financial relationships with peptide vendors.