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Somatropin
Peptology Ltd. · Recovery and anabolic peptides
GH 191AA 36 IU (3 vials) – recombinant human growth hormone (rhGH, somatropin): a 191-amino-acid protein structurally identical to pituitary growth hormone; a research substance for studies of the GH/IGF‑1 axis. Purity above 99%, laboratory certificate for every batch.
📦 The product is in our EU warehouse – delivery within 3–5 working days.
139,00 € · Out of stock
For research use only / Not a medicine



| Purity | >99% |
|---|---|
| Method | HPLC + LC/MS |
| Laboratory | Analiza Białek |
| Batch | 0226 |
Last updated: 23/07/2026
This page concerns Somatropin in the 3 pcs × 36 IU format (three vials, 108 IU in total, ~36 mg). Somatropin (GH 191AA) is recombinant human growth hormone (rhGH) — a protein with a 191-amino-acid chain, identical to the structure of the growth hormone produced naturally by the pituitary gland. The "191AA" designation indicates that the molecule is bioidentical to natural HGH (in contrast to older 192AA forms with an additional methionine). It is the 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-made 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 applications, not intended for use in humans or animals. It belongs to the category recovery and anabolic peptides.
This format — 3 pcs × 36 IU — contains 108 IU (~36 mg) in total and is intended for longer, multi-week or parallel protocols, with a more favorable unit cost than a single vial. Somatropin is also available in the smaller 1 pc × 36 IU format and in the largest 100 IU. The product is supplied with purity above 99% and independent laboratory analysis (CoA for every batch).
Somatropin is available in three packaging formats. The substance is identical in all of them (recombinant somatropin 191AA, the same purity); only the total amount and unit cost differ.
1 PC × 36 IU
36 IU (~12 mg) in one vial — for single and shorter research protocols.
3 PCS × 36 IU
Triple format (this page)
3 × 36 IU = 108 IU (~36 mg) — for longer, multi-week or parallel protocols, more favorable unit cost.
100 IU
100 IU (~33 mg) — a large package for long-term, intensive protocols; the lowest unit cost.
All three formats contain identical somatropin 191AA with purity > 99% and a laboratory certificate for the batch. The choice depends on the scale of the protocol, not on the quality of the substance.
In the clinical literature, somatropin is described as a bioidentical growth hormone that acts directly on the GH receptor and triggers the cascade of growth and regeneration. The three effects below together explain its broad metabolic and anabolic action.
GH RECEPTOR
Binds the growth hormone receptor (GHR) in tissues (especially the liver), triggering the JAK2/STAT5 pathway — directly, without the involvement of the pituitary.
IGF-1 PRODUCTION
Stimulates hepatic IGF-1 production — the main mediator of growth, protein synthesis and tissue regeneration.
LIPOLYSIS & ANABOLISM
Supports lipolysis (fat burning), lean mass growth, collagen synthesis and bone mineralization.
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 stage: it is ready-made 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 thus an intermediate link: the GH hormone itself, which only 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.
Somatropin is a protein with a well-described pharmacokinetic profile. Its relatively short presence in plasma contrasts with the longer, indirect action through IGF-1.
All three formats contain the same, identical somatropin 191AA — they differ only in the total amount and unit cost. The table below helps you choose the package appropriate for the scale of the research protocol.
| 1 pc × 36 IU | 3 pcs × 36 IU (this page) | 100 IU | |
|---|---|---|---|
| Package contents | 1 vial × 36 IU | 3 vials × 36 IU | 100 IU package |
| Total amount | 36 IU (~12 mg) | 108 IU (~36 mg) | 100 IU (~33 mg) |
| Substance and purity | Somatropin 191AA, > 99% | Identical, > 99% | Identical, > 99% |
| Unit cost (per IU) | Standard | More favorable | Lowest |
| For which protocol scale | Single / shorter series | Longer or parallel protocols | Long-term, intensive protocols |
The choice between formats depends solely on the scale and duration of the research protocol. The substance, purity and batch certificate are identical in all three versions. You will find the other formats here: 1 pc × 36 IU and 100 IU.
Somatropin has one of the best-documented profiles among GH-axis molecules. Below are the most important areas from the literature. The data concern pharmaceutical forms of somatropin.
In clinical studies, recombinant somatropin 191AA showed good tolerability and a low risk of immunogenicity thanks to its bioidentity with natural GH. The pharmacokinetic profile (short half-life, indirect action through IGF-1) is well characterized.
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, reduction of adipose tissue and improved bone mineralization, as well as an increase in IGF-1 concentrations.
Note: The information about clinical studies concerns 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.
All information provided concerns 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.
Important: The information below describes doses described in studies and the clinical literature on somatropin. It is provided for scientific and informational purposes and does not constitute a recommendation for individual use, medical advice or administration instructions. The research-grade somatropin offered by Peptology is not a registered drug.
In clinical protocols, somatropin is usually administered subcutaneously, in low daily doses; the IU/mg conversion is helpful. The 3 × 36 IU (108 IU) format is convenient for longer protocols in which a single vial might not be enough:
In GH-axis protocols, somatropin is sometimes paired 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.
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.
Frequently described (dose-dependent)
Less frequent
Requires attention
Most side effects are dose-dependent and reversible after dose adjustment. Because of 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.
Somatropin 3 pcs × 36 IU is supplied as a lyophilized (freeze-dried) powder in three separate vials — each is reconstituted individually, as the protocol requires. 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 its lifespan.
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.
It is recombinant human growth hormone with a 191-amino-acid chain, bioidentical to the GH produced by the pituitary. It acts directly on the GH receptor and stimulates the production of IGF-1. Unlike secretagogues, it is the hormone itself, not an agent that stimulates its secretion.
Three vials of 36 IU, i.e. 108 IU (~36 mg) in total. That is about three times a single package of 1 pc × 36 IU, with a more favorable unit cost — convenient for longer or parallel protocols.
The substance is identical in all of them — only the amount and unit cost differ. 1 pc × 36 IU is 36 IU (~12 mg) for single protocols; this format (3 pcs × 36 IU) is 108 IU (~36 mg) in total for longer or parallel protocols; and 100 IU (~33 mg) is the maximum package with the lowest unit cost.
The conversion for somatropin is about 3 IU = 1 mg, so 36 IU is roughly 12 mg, and this 3 × 36 IU (108 IU) format is about 36 mg in total. For precise calculations, use the peptide calculator.
Secretagogues (Ipamorelin, CJC-1295) stimulate the pituitary to release its own GH, preserving physiological regulation. Somatropin delivers ready-made GH directly — it acts more strongly and independently of the pituitary, but without natural feedback.
The lyophilized vials are stored at room temperature, protected from light and moisture; in the 3-pack format, subsequent vials are reconstituted as needed. 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.
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.
Researchers working with somatropin often also consider other formats and GH-axis tools — smaller and larger packaging, GH secretagogues and the final effector IGF-1. Each of the products below has a certificate of purity above 99%:
Somatropin 1 pc × 36 IU
Smaller package (36 IU) — single protocols
Somatropin 100 IU
Maximum package (~33 mg) — long protocols
Ipamorelin
Selective GH secretagogue
CJC-1295 without DAC
GHRH analog (GH axis)
IGF-1 LR3
Final effector of the GH–IGF-1 axis
Peptide Matrix Water™
Stabilizing solution for reconstitution
See the full catalog: Recovery and anabolic peptides · Solutions for peptides · All peptides · Blog on peptide research
Research warning: Somatropin (HGH 191AA) 3 pcs × 36 IU is offered exclusively for scientific research and in vitro purposes. It is not a medicinal product, is not an approved drug, is not intended for use in humans or animals, and does not replace medical advice. All information about clinical studies concerns pharmaceutical forms of somatropin and is provided for scientific and informational purposes; it does not constitute a claim about the effect of the research-grade product offered by Peptology.
Standardized protocol applicable to all research peptides in the Peptology catalogue. To calculate the solution concentration (mg/mL) for each vial, use the peptide reconstitution calculator.
1. SOLVENT
2. RECONSTITUTION
Add the solvent down the side of the vial, without shaking, wait 10–15 min.
3. CALCULATION
Calculator → concentration mg/mL
4. STORAGE
+2 °C to +8 °C, up to 60 days with Peptide Matrix Water
| Parameter | Value |
|---|---|
| Form | Lyophilized powder |
| Solvent | Peptide Matrix Water |
| Reconstitution volume | 1–3 mL — maximum 3 mL (capacity of the standard vial) |
| Storage before reconstitution | Room temperature, protected from direct light (refrigeration not required) |
| After reconstitution | Up to 60 days at +2 °C to +8 °C with Peptide Matrix Water |
Precision pipette
Calibrated, 100–1000 µL — for accurately measuring the volume of solvent added to the vial.
70% alcohol swabs
Two swabs — to disinfect the peptide vial and the solvent vial.
Stabilized solvent for lyophilized peptides. Why this one.
| ✅ Correct | ❌ Mistake |
|---|---|
| Disinfect the vial caps and the work surface with 70% alcohol; wear gloves | Working without disinfection |
| Add the solvent slowly along the vial wall | Direct jet onto the powder — foaming and denaturation |
| Gentle rolling between the palms | Shaking — foam, which denatures peptides |
| 10–15 minutes waiting at room temperature | Mechanical mixing or heating |
| Visual check: clear, particle-free | Working with a cloudy or discolored solution |
⚠️ Maximum 3 mL solvent. The standard vial does not accommodate larger volumes — do not exceed during reconstitution.
👉 For any vial and solvent volume — use the calculator. It calculates the concentration (mg/mL, µg/µL) and the volume per sample (mL, µL).
BEFORE RECONSTITUTION
Room temperature, protected from direct light, in original packaging. Refrigerator not required.
AFTER RECONSTITUTION
+2 °C to +8 °C, up to 60 days with Peptide Matrix Water. Discard any remainder after this period.
FREEZING
Not recommended. Freeze/thaw cycles degrade peptide structure.
1. Shaking "to dissolve faster"
Foam = denaturation. Only gentle rolling between the palms.
2. Inappropriate solvent
For peptide stability use only sterile, specially formulated solvent — recommended Peptide Matrix Water.
3. Ignoring slight turbidity
Not fully clear = the sample does not meet the criteria for use.
4. Taking it out of the refrigerator "for an hour–two"
Short exposures add up and compromise stability.
Research status: All Peptology products are intended for laboratory and research use only. They are not medicinal products, not approved for human or veterinary use and do not substitute medical advice. The described protocol is standard laboratory practice for working with lyophilized peptides.
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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).
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.
The product is for research use only and does not require a prescription.
You can buy Somatropin in Europe online from Peptology, from 139,00 €. 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.
