Somatropin 100 IU – Growth Hormone (HGH)

What is Somatropin (Somatropin, HGH 191AA) — 100 IU?

This page concerns Somatropin in the 100 IU vial size (large pack, ~33 mg) — the largest pack size in our catalog. Somatropin (Somatropin, GH 191AA) is recombinant human growth hormone (rhGH) — a protein with a chain of 191 amino acids, identical to the structure of the growth hormone naturally produced by the pituitary gland. The "191AA" designation indicates that the molecule is bioidentical to natural HGH (unlike older 192AA forms with an additional methionine). It is growth hormone itself, not an agent that stimulates its secretion.

This is the key difference from the rest of the category. Secretagogues and GHRH analogs — like Ipamorelin, CJC-1295 or Sermorelin — stimulate the pituitary to release its own GH. Somatropin delivers ready growth hormone directly, acting independently of pituitary function. Then, like natural GH, it stimulates the liver to produce IGF-1 — the main mediator of growth and regeneration.

The research-grade Somatropin offered by Peptology is not a medicinal product — it is a lyophilized research hormone intended exclusively for scientific and in vitro use, not intended for use in humans or animals. It belongs to the category recovery and anabolic peptides.

This format — 100 IU (~33 mg) — is the largest pack, with the lowest cost per unit, intended for long and intensive research protocols. Somatropin is also available in smaller vial sizes: 1 pc × 36 IU and 3 pcs × 36 IU (108 IU). The product is supplied with purity above 99% and independent laboratory analysis (CoA for every batch).

Available vial sizes: 36 IU, 3 × 36 IU and 100 IU

Somatropin is available in three pack formats. The substance is identical in all of them (recombinant somatropin 191AA, the same purity); only the total amount and unit cost differ.

All three formats contain identical somatropin 191AA with purity > 99% and a batch laboratory certificate. The choice depends on the protocol scale, not on the quality of the substance.

How Somatropin (100 IU) works — direct growth hormone

In the clinical literature, somatropin is described as a bioidentical growth hormone that acts directly on the GH receptor and triggers a cascade of growth and regeneration. The three effects below together explain its broad metabolic and anabolic action.

Why a "direct hormone" differs from secretagogues

The growth axis works as a cascade: GHRH/GHRP → pituitary → GH → IGF-1. GHRH analogs (CJC-1295, Sermorelin) and GHRP secretagogues (Ipamorelin) act "higher up" — they stimulate the pituitary, and the effect depends on its reserve and preserves natural pulsatility. Somatropin bypasses this step: it is ready GH and acts directly on tissue receptors. This gives a stronger, more direct elevation of GH/IGF-1, but without physiological feedback regulation.

Even "lower" in the cascade is IGF-1 LR3 — the final effector. Somatropin is therefore an intermediate link: the GH hormone itself, which then generates IGF-1. This data comes from the clinical literature and does not constitute a claim about the effect of the research-grade product.

Pharmacokinetics and IU / mg conversion

Somatropin is a protein with a well-described pharmacokinetic profile. Its relatively short plasma presence contrasts with the longer, indirect action via IGF-1.

• Structure: recombinant human growth hormone, 191 amino acids (bioidentical to pituitary GH)
• IU / mg conversion: about 3 IU = 1 mg — so this 100 IU pack ≈ 33 mg (for comparison, 36 IU ≈ 12 mg)
• Half-life: on the order of 3–4 hours after subcutaneous administration
• Indirect action: effects last longer thanks to the induction of IGF-1 (with an extended profile)
• Target: the GH receptor (GHR), JAK2/STAT5 pathway
• Research schedule: in clinical protocols usually daily subcutaneous administration, low daily doses

Comparison: 36 IU vs 3 × 36 IU vs 100 IU

All three formats contain the same, identical somatropin 191AA — they differ only in total amount and unit cost. The table below helps you choose the pack suited to the scale of your research protocol.

The choice between formats depends solely on the scale and duration of the research protocol. The substance, purity and batch certificate are identical across all three versions. You can find the smaller vial sizes here: 1 pc × 36 IU and 3 pcs × 36 IU.

Clinical and research data on somatropin

Somatropin has one of the best-documented profiles among GH-axis molecules. Below are the most important areas from the literature. The data concern the pharmaceutical forms of somatropin.

Safety and pharmacokinetics

In clinical trials, recombinant somatropin 191AA showed good tolerance and low immunogenicity risk thanks to bioidentity with natural GH. The pharmacokinetic profile (short half-life, indirect action via IGF-1) is well characterized.

Growth hormone deficiency and body composition

Somatropin is used clinically in the treatment of growth hormone deficiency (in children and adults) and other indications. In studies it is associated with improved body composition, increased lean mass, reduced fat tissue and improved bone mineralization, as well as increased IGF-1 concentrations.

Note: The clinical trial information concerns the pharmaceutical forms of somatropin and is presented for scientific and informational purposes. It does not constitute medical advice, a recommendation for use or a claim about the effect of the research-grade product offered by Peptology.

Somatropin 100 IU profile at a glance

• Bioidentical growth hormone (191AA) — GH itself, not an agent that stimulates the pituitary
• Direct GH receptor activation (JAK2/STAT5), independent of pituitary reserve
• Strong IGF-1 induction — the main mediator of growth and regeneration
• Supports lipolysis, lean mass, collagen synthesis and bone mineralization in research models
• 100 IU format (~33 mg) — largest pack, lowest unit cost, for long-term protocols

All information provided concerns the pharmaceutical forms of somatropin and the clinical literature; it should not be interpreted as a promise of effect, an instruction for use or a claim about the effect of the research-grade product offered by Peptology.

Research dosing protocols

In clinical protocols, somatropin is usually administered subcutaneously, in low daily doses; the IU/mg conversion is helpful. The large 100 IU format has the lowest unit cost and suits long protocols where hormone consumption is high:

• Conversion: ~3 IU = 1 mg (100 IU ≈ 33 mg; 36 IU ≈ 12 mg)
• The literature describes low daily doses (e.g. on the order of 2–3 IU/day in anti-aging contexts)
• Route of administration: subcutaneous or intramuscular, per the research protocol
• Monitoring: in studies the dose is selected based, among other things, on IGF-1 levels

In GH-axis protocols, somatropin is sometimes combined with secretagogues (Ipamorelin, CJC-1295) or with regenerative peptides (BPC-157). These schedules come from the research literature and do not constitute a recommendation for self-administration.

Side effects and safety

The side-effect profile of somatropin is well described in the clinical literature and is mostly dose-dependent. Because it is a direct hormone (stronger than secretagogues), some effects result from excessive activation of the GH/IGF-1 axis.

Most side effects are dose-dependent and reversible after adjustment. Due to the direct effect on the GH/IGF-1 axis and glucose, monitoring is important. This information is scientific in nature and does not constitute an instruction for use.

Storage and reconstitution (100 IU)

Somatropin 100 IU is supplied as a lyophilized (freeze-dried) powder. In lyophilized form it is stable at room temperature, protected from light and moisture — refrigeration before reconstitution is not mandatory. After reconstitution, stability depends on the solvent used, with Peptide Matrix Water™ significantly extending the lifespan.

• Before reconstitution: room temperature, in the original packaging, protected from light and moisture. Refrigeration is not mandatory.
• After reconstitution with Peptide Matrix Water™: stability in the refrigerator +2 °C to +8 °C for up to 60 days under appropriate laboratory conditions — the stabilizing formula extends the lifespan relative to standard solvents.
• After reconstitution with bacteriostatic or sterile water: stability in the refrigerator +2 °C to +8 °C for up to 28 days under appropriate conditions. Do not refreeze the reconstituted solution.
• Reconstitution: in a laboratory setting, Peptide Matrix Water™, bacteriostatic water or sterile water for injection is usually used, depending on the protocol.
• Volume: maximum 3 mL of solvent per vial (standard vial capacity). For a precise dose calculation in IU/mg, use the peptide calculator — particularly important at the large 100 IU dosage.
• Homogenization: add the solvent slowly down the vial wall, without vigorous shaking — protein bonds are sensitive to mechanical stress. Swirl gently, do not shake.

Laboratory tip: With your order, you can add Peptide Matrix Water™ to the cart — a stabilizing solution designed for working with reconstituted research peptides and proteins. More in the article Bacteriostatic water vs acetic acid vs matrix water.

Frequently asked questions — Somatropin 100 IU

What exactly is somatropin (HGH 191AA)?

It is recombinant human growth hormone with a chain of 191 amino acids, bioidentical to the GH produced by the pituitary. It acts directly on the GH receptor and stimulates IGF-1 production. Unlike secretagogues, it is the hormone itself, not an agent that stimulates its secretion.

How much somatropin does the 100 IU format contain?

100 IU is about 33 mg of somatropin — the largest pack in the catalog, with the lowest cost per unit. It is a convenient choice for long, intensive protocols; the smaller formats are 1 pc × 36 IU and 3 pcs × 36 IU.

How do the 36 IU, 3 × 36 IU and 100 IU formats differ?

The substance is identical in all of them — only the amount and unit cost differ. 1 pc × 36 IU (~12 mg) for single protocols; 3 pcs × 36 IU (108 IU, ~36 mg) for longer or parallel protocols; and this 100 IU format (~33 mg) is the largest pack with the lowest unit cost, for long-term, intensive protocols.

How much is 100 IU in milligrams?

The conversion for somatropin is about 3 IU = 1 mg, so 100 IU is roughly 33 mg. For precise calculations, use the peptide calculator.

How does somatropin differ from secretagogues like Ipamorelin?

Secretagogues (Ipamorelin, CJC-1295) stimulate the pituitary to release its own GH, preserving physiological regulation. Somatropin delivers ready GH directly — it acts more strongly and independently of the pituitary, but without natural feedback.

How is somatropin stored and reconstituted?

Lyophilized somatropin is stored at room temperature, protected from light and moisture. After reconstitution, stability depends on the solvent: with Peptide Matrix Water™ — up to 60 days in the refrigerator +2 °C to +8 °C; with bacteriostatic or sterile water — up to 28 days. Avoid refreezing.

Where to buy somatropin for research?

Peptology offers somatropin 191AA (1 pc × 36 IU, 3 pcs × 36 IU and 100 IU) as a research product with confirmed purity above 99% and independent laboratory analysis for every batch. Fast shipping, discreet packaging and certificates of purity. For scientific background, also see the article Peptides — what they are, how they work, main categories and safety profile.

Related products in the Peptology catalog

Researchers working with somatropin often also consider the smaller formats and GH-axis tools — GH secretagogues and the final effector IGF-1. Each of the products below has a certificate of purity above 99%:

See the full catalog: Recovery and anabolic peptides · Solutions for peptides · All peptides · Blog on peptide research

Laboratory reconstitution

Laboratory protocol — reconstitution, research protocols, storage

Standardized protocol valid for all research peptides in the Peptology catalogue. To calculate the solution concentration (mg/mL) for each vial, use the peptide reconstitution calculator.

60-second protocol

Quick reference

What you need

Five rules for reconstitution

Calculating concentration

Storage

Four mistakes to avoid

Shipping information

🚚 Shipping information

• Products in our warehouse – orders placed by 15:00 on working days are dispatched the same day, later orders on the next working day.

• Delivery with GLS to your address in 3–5 working days.

• Shipping costs €5 and is free from €50.

Frequently Asked Questions (FAQ)

💡 Frequently Asked Questions about Somatropin 100 IU

In what form is Somatropin supplied and how should it be stored?

It is supplied as a lyophilized (freeze-dried) powder in a sealed vial. Store the unopened vial dry and protected from light, ideally at 2–8 °C. After laboratory reconstitution, keep the solution at 2–8 °C and use it within the period stated in the “Laboratory reconstitution” tab (up to 60 days with Peptide Matrix Water).

What purity does Somatropin have and how is it tested?

Every batch has a purity of 99% or higher, confirmed by HPLC and mass spectrometry (MS) and documented in a certificate of analysis (CoA). The report for the current batch is shown in the “Laboratory Analysis” tab.

Is a prescription required to purchase?

The product is intended for research purposes and laboratory use only, therefore a prescription is not required for its acquisition.

Where can I buy Somatropin in Europe and what does it cost?

You can buy Somatropin in Europe online from Peptology, from 128,00 €. Delivery with GLS in 3–5 working days. Shipping is free from 50,00 €. Payment by card. Purity 99%+, with an HPLC report for every batch.

Laboratory Analysis

Somatropin (GH 191AA) - 100 IU - Batch - 0226 - Purity