Compare Peptides
Select any two compounds for a side-by-side comparison of mechanism, uses, risks, and FDA regulatory status.
Popular comparisons
IGF-1 LR3
Insulin-like Growth Factor-1 Long R3, Long R3 IGF-1
A naturally occurring glycoprotein that acts as a potent inhibitor of myostatin — the protein that limits muscle growth. Follistatin 344 is the most common isoform used in research contexts. Inhibiting myostatin theoretically removes the body's natural brake on muscle development.
A synthetic analog of insulin-like growth factor-1 (IGF-1) with an extended half-life due to a modified arginine-3 sequence. IGF-1 is naturally produced in the liver in response to growth hormone. The LR3 variant is approximately 3x more potent than native IGF-1 and resists binding to IGF-binding proteins, extending its activity.
Binds to and neutralizes myostatin (GDF-8) and activin, preventing them from signaling through the ActRIIB receptor. This removes the inhibitory signal on muscle satellite cells, allowing greater muscle fiber growth and regeneration. Also affects bone density and fat metabolism through activin pathway modulation.
Binds to IGF-1 receptors throughout the body, stimulating cell growth, proliferation, and differentiation. Promotes protein synthesis, glucose uptake, and fat oxidation. Activates the PI3K/Akt/mTOR pathway — the primary anabolic signaling cascade. Unlike GH secretagogues, IGF-1 LR3 acts directly at the tissue level rather than through the pituitary.
- Muscle mass enhancement
- Strength improvement
- Muscular dystrophy research
- Recovery from muscle-wasting conditions
- Muscle growth and hypertrophy
- Recovery from injury
- Fat loss
- Anti-aging protocols
- Athletic performance enhancement
- Very limited human clinical data
- Potential for uncontrolled muscle growth
- Tendon and connective tissue may not keep pace with muscle growth
- Cardiovascular effects of myostatin inhibition not fully characterized
- Long-term safety completely unknown
- High potential for misuse in athletic contexts
- Hypoglycemia (blood sugar drop) — significant risk, especially post-workout
- Potential tumor growth promotion (IGF-1 pathway implicated in cancer)
- Acromegaly-like effects with chronic high-dose use
- Joint pain
- Water retention
- Limited long-term human safety data
- High abuse potential in athletic contexts
Not FDA-approved and not on any compounding list. Available as a research chemical. Myostatin inhibition is an active area of pharmaceutical research for muscular dystrophy — several drug candidates are in clinical trials, but follistatin itself has not advanced to approved drug status.
Not FDA-approved and not on any compounding list. Available as a research chemical. One of the more potent anabolic peptides — the hypoglycemia risk is real and requires careful dosing. Not affected by the 2026 regulatory changes.
This comparison is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide therapy.