Growth-hormone secretagogues and related peptides are studied for lean-mass support, strength, and training recovery.
11 peptides commonly researched for this goal. Tap any card for the full guide.
TB-500 is the synthetic cousin of full-length Thymosin Beta-4, used off-label for full-body recovery rather than a single injury site.
Read the guideWidely considered the gentlest GH-releasing peptide in its class. Commonly paired with CJC-1295 in research stacks.
Read the guideA GHRH analog that comes in a long-acting (DAC) and short-acting (no-DAC/Mod GRF) form. The choice materially changes the risk/use profile.
Read the guideThe most 'clinically legitimate' GH secretagogue on this list. Formerly FDA-approved, now prescribed off-label at anti-aging clinics.
Read the guideA genuinely FDA-approved peptide (for visceral fat in HIV lipodystrophy) that's widely used off-label for general body composition.
Read the guideAn older, stronger GH-releasing peptide. More effective per dose than Ipamorelin, but with a rougher side-effect profile.
Read the guideThe original ghrelin-mimetic GHRP. Famous (or notorious) for making users very hungry.
Read the guideThe most potent common GHRP, with a unique secondary cardioprotective research angle.
Read the guideTechnically not a peptide, but it belongs in this catalog because it's almost always discussed in the same breath. An oral GH secretagogue with real blood-sugar tradeoffs.
Read the guideA muscle-growth peptide popular in bodybuilding circles that carries a real, underappreciated hypoglycemia risk.
Read the guideA 'myostatin inhibitor' whose exciting animal data mostly comes from gene therapy studies, not the injectable peptide form people actually buy.
Read the guideMost peptides people group under "muscle growth" fall into two buckets. The larger one is growth-hormone secretagogues: compounds like Ipamorelin, CJC-1295, Sermorelin, Tesamorelin, GHRP-2, GHRP-6, and Hexarelin. They don't add growth hormone directly. They nudge your pituitary to release more of its own, which raises GH and downstream IGF-1, the signals tied to protein synthesis and lean-mass support. MK-677 works on the same axis by mouth, though it isn't technically a peptide.
The second bucket is more direct or more about recovery. IGF-1 LR3 is a growth-factor analog studied for muscle signaling. Follistatin 344 is discussed as a myostatin inhibitor. TB-500, a Thymosin Beta-4 fragment, is used off-label for whole-body recovery rather than mass itself. Be clear-eyed on the evidence. Some of these have extensive research behind them, others are backed mostly by animal work, and the injectable forms people buy often aren't the versions that produced the exciting study data.
| Peptide | Category | Studied for | Evidence |
|---|---|---|---|
| TB-500Thymosin Beta-4 fragment | Healing & Recovery | Recovery & Healing, Muscle Growth | Extensive research |
| IpamorelinGH releasing peptide (GHRP) | Growth Hormone Secretagogues | Muscle Growth, Longevity | Extensive research |
| CJC-1295CJC-1295 with DAC | Growth Hormone Secretagogues | Muscle Growth, Longevity | Extensive research |
| SermorelinGHRH analog | Growth Hormone Secretagogues | Muscle Growth, Longevity | Extensive research |
| TesamorelinEgrifta | Growth Hormone Secretagogues | Muscle Growth, Longevity | Extensive research |
| GHRP-2GH releasing peptide (GHRP) | Growth Hormone Secretagogues | Muscle Growth, Longevity | Moderate research |
| GHRP-6GH releasing peptide (GHRP) | Growth Hormone Secretagogues | Muscle Growth, Longevity | Moderate research |
| HexarelinGH releasing peptide (GHRP) | Growth Hormone Secretagogues | Muscle Growth, Longevity | Moderate research |
| MK-677 (Ibutamoren)Non-peptide GH secretagogue | Growth Hormone Secretagogues | Muscle Growth, Longevity | Extensive research |
| IGF-1 LR3Growth factor analog | Muscle & Performance | Muscle Growth | Moderate research |
| Follistatin 344Myostatin inhibitor | Muscle & Performance | Muscle Growth | Limited research |
GH secretagogues raise growth hormone in a more pulsatile, closer-to-natural pattern than injecting HGH. Higher GH lifts IGF-1, and IGF-1 is one of the main drivers of muscle protein synthesis and repair after training. That's the theory these compounds run on. The class splits into two mechanisms that get stacked together: GHRH analogs like CJC-1295, Sermorelin, and Tesamorelin, and ghrelin-mimetic GHRPs like Ipamorelin, GHRP-2, GHRP-6, and Hexarelin. Potency and side effects vary a lot. Ipamorelin is considered the gentlest, GHRP-6 is notorious for hunger, and Hexarelin is the strongest of the common GHRPs. None of this is a shortcut around training, sleep, and protein.
Honestly, the picture is mixed and mostly indirect. GH secretagogues reliably raise GH and IGF-1, but a bump in those markers doesn't automatically translate to more muscle on a natural lifter, and human body-composition data is thinner than the marketing suggests. Tesamorelin and Sermorelin have real clinical pedigrees, though for specific approved uses, not bodybuilding. IGF-1 LR3 and Follistatin 344 have a more direct muscle rationale but carry bigger question marks: IGF-1 LR3 has a real, underappreciated hypoglycemia risk, and Follistatin's impressive data comes largely from gene-therapy studies, not the injectable peptide. Recovery peptides like TB-500 may help you train more, which is its own indirect route to growth.
Legal and safety status is all over the map here, and it matters. A few of these are FDA-approved for specific conditions, like Tesamorelin, and are used off-label. Most of the GHRPs and research peptides are not approved for muscle or performance and are sold as research chemicals with no manufacturing oversight, so purity and dosing accuracy are genuine unknowns. Real tradeoffs come up: GH secretagogues can raise blood sugar and hunger, MK-677 has clear blood-sugar effects, and IGF-1 LR3 can drop blood glucose sharply. This page is educational, not medical advice, and not a protocol. Anything injectable or hormone-altering is a conversation to have with a qualified clinician who can weigh your own bloodwork and goals.
There's no single best one, and the honest answer depends on your goal. For GH-axis support, Ipamorelin paired with CJC-1295 is the most common research stack, and Sermorelin and Tesamorelin have the strongest clinical backgrounds. For a more direct muscle angle, people look at IGF-1 LR3 or Follistatin 344, but both carry real caveats and thinner human evidence.
GH secretagogues reliably raise growth hormone and IGF-1, the signals linked to muscle repair and protein synthesis. Whether that turns into meaningful extra muscle for a natural, well-trained lifter is less certain, and the human body-composition data is thinner than the hype. Recovery peptides like TB-500 may help indirectly by letting you train harder and more often.
It varies by compound. A handful, like Tesamorelin, are FDA-approved for specific conditions and used off-label. Most GHRPs and research peptides aren't approved for muscle or performance and are sold as research chemicals without manufacturing oversight, so purity is a real unknown. Side effects range from raised blood sugar and hunger to, with IGF-1 LR3, hypoglycemia.
They're compounds that prompt your own pituitary to release more growth hormone rather than injecting HGH directly. Two types get combined: GHRH analogs like CJC-1295, Sermorelin, and Tesamorelin, and ghrelin-mimetic GHRPs like Ipamorelin, GHRP-2, GHRP-6, and Hexarelin. Higher GH raises IGF-1, which supports muscle protein synthesis and recovery. MK-677 does something similar by mouth.
TB-500 is a synthetic fragment of Thymosin Beta-4, used off-label for whole-body recovery rather than a single injury site. On a muscle page it shows up as a recovery peptide, not a mass-builder. The idea is that better soft-tissue repair lets you train more consistently. It has a fair amount of research interest but limited human trial data for these uses.
GH secretagogues work upstream, raising your own growth hormone so IGF-1 rises naturally. IGF-1 LR3 is a growth-factor analog that acts more directly on muscle-growth signaling. It's popular in bodybuilding circles but carries a real, underappreciated hypoglycemia risk, since it can lower blood sugar sharply. That makes it riskier to handle than the gentler GH-axis peptides.
Educational information only. This is not medical advice. Peptide AI is an informational and tracking platform. Everything on this page is for general education. It is not a substitute for professional medical advice and is not a recommendation to use any compound. Many peptides listed here are research compounds the FDA has not approved for human use. Talk to a qualified, licensed healthcare provider before you start, change, or stop any protocol.
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