Name: ProSpec Bio Growth Hormone Releasing Peptide-4
Brand: ProSpec Bio
SKU: PSB-HOR-022
Availability: InStock

<h2 data-section-id="1mowz68" data-start="0" data-end="29">What are peptide hormones?</h2>
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Peptide hormones are recombinant proteins built from amino acid chains that regulate cell metabolism and growth, with insulin the most widely used in cell culture as a component of serum-free media and the ITS (insulin-transferrin-selenium) supplement combination, and glucagon used in some metabolic and hepatocyte signaling studies. Related entities include ITS media supplements, adipocyte differentiation cocktails (insulin, dexamethasone, IBMX), insulin receptor (INSR) and IGF-1 receptor cross-reactivity, and serum-free CHO/hybridoma media formulation.
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<h2 dir="ltr">What you'll find in this category: </h2>
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Cell-Surface Receptor Bindings: Pure peptide chains engineered to trigger immediate, predictable intracellular signaling loops.
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Endocrine Signaling Assets: Highly stable hormones prepared to model systemic metabolic and physiological pathways.
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Targeted Tracking Assets: Streamlined molecular tools designed to minimize hands-on time and eliminate cross-reactive variables.
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<h2 data-section-id="100hbou" data-start="775" data-end="816">How to choose peptide hormone products</h2>
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Recombinant insulin source and grade
Recombinant human insulin produced in E. coli or yeast is standard for cell culture media. Cell-culture-grade insulin is formulated for solubility and stability in defined media, distinct from pharmaceutical insulin formulations that contain excipients intended for injection use.
Carrier-free vs. carrier-added formulation
Carrier-free insulin (no BSA) is preferred for animal-component-free (ACF) serum-free media intended for cell therapy-adjacent research, while carrier-added insulin offers improved stability for routine serum-free CHO or hybridoma culture.
Concentration and ITS context
Insulin in standard ITS supplements is typically used at low microgram per mL concentrations (often around 1&ndash;10 &micro;g/mL), substantially higher in mass terms than most growth factors. Confirm whether a protocol calls for insulin alone or as part of a pre-mixed ITS supplement, since this changes dosing strategy and media balance.
Insulin vs. IGF-1 cross-reactivity
At higher concentrations, insulin can activate the IGF-1 receptor in addition to the insulin receptor, which is relevant in serum-free media where both insulin and IGF-1 may be present. Protocols sensitive to this effect may specify insulin analogs with reduced IGF-1R binding.
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<h2 data-section-id="1fljvas" data-start="3031" data-end="3056">Specifications context</h2>
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Recombinant insulin for cell culture is typically supplied at purity greater than 95&ndash;98% by HPLC, with concentration specified in micrograms per mL or international units depending on formulation. Pack sizes for academic laboratories commonly range from 10 milligrams to 1 gram due to the relatively high mass concentrations used compared to cytokines and growth factors. As of 2026, ITS supplements remain a standard, cost-effective component of serum-free media across academic and industrial cell culture workflows, with insulin as the dominant functional driver of the combination.
This category sits within MBP's growth factors and hormones catalog alongside insulin-like growth factors, which share partial receptor signaling overlap with insulin, and amino acid derived hormones, which are often co-formulated in differentiation media. Laboratories developing adipocyte differentiation protocols may also review steroid hormones for dexamethasone sourcing. MBP's specialist team can help confirm insulin grade and ITS formulation options for serum-free media development.
Need to stock up on bulk quantities for your testing runs? <a href="https://mbpinc.net/contact-us">Drop a line to the MBP desk</a>, and we&rsquo;ll get your peptide hormone setup squared away.

Peptide Hormones

ProSpec Bio

Key Specifications

ProSpec Bio Growth Hormone Releasing Peptide-4

Growth Hormone Releasing Peptide-4 by ProSpec Bio is a synthetic growth hormone-releasing peptide (GHRP) made by chemical synthesis, a 4-amino-acid peptide of 607.73 Da that is more than 97% pure. It is supplied lyophilized in 5 mg, 25 mg and 100 mg sizes for growth hormone axis research. Its molecular formula is C34H37N7O4.