Description
PrymaLab · Research Use Only
HCG 10000iu
Sold in units of activity · which are not a quantity of anything
Every other article in this catalogue is sold by mass. HCG peptide is sold in international units. A unit is not a quantity of anything, and the distinction is not pedantic. It is a measure of biological activity, defined by comparison against a reference preparation held by a standards laboratory.
Specification Table
| Property | Value |
|---|---|
| Compound | Human chorionic gonadotropin |
| Article type | Glycoprotein hormone, not a synthetic peptide |
| Structure | A heterodimer of two different subunits, held together non-covalently |
| Alpha subunit | Shared with the other glycoprotein hormones in this family |
| Beta subunit | Unique to this hormone and the source of its receptor specificity |
| Approximate mass | Around 36 kDa, varying with glycosylation |
| Why the mass varies | The carbohydrate is heterogeneous, so intact mass is a distribution |
| Potency basis | International units, defined by bioassay against a WHO reference preparation |
| Relationship of units to mass | Not a constant. It depends on the preparation and on the standard it was calibrated against |
| Commonly quoted figure for purified material | In the region of ten thousand units per milligram |
| Consequence for this vial | A nominal 10000 unit fill is roughly a milligram of material, approximately |
| Subunit dissociation | The two subunits can separate. Separated subunits are inactive |
| Regulatory status | Approved formulations exist. Material supplied here is not one of them |
| Storage, lyophilized | 2-8°C. Avoid freezing solutions and avoid agitation |
What Is an International Unit of HCG Peptide?
The unit exists because measuring hcg peptide by mass does not give a usable number.
A glycoprotein hormone carries attached carbohydrate that varies between molecules in the same preparation, so a milligram of one batch is not chemically identical to a milligram of another.
More importantly, the biological activity varies with that carbohydrate. Two preparations of identical protein content can differ measurably in what they do.
The response to that problem, worked out for hormones long before anyone could sequence them, was to define potency by comparison rather than by composition.
A standards laboratory holds a reference preparation. A test material is run alongside it in a defined bioassay, and its potency is expressed as a ratio.
That ratio, scaled by the units assigned to the standard, is the potency in international units.
So a unit is a statement about behaviour in an assay, and it is meaningful only relative to the preparation it was measured against.
When a new international standard replaces an old one, the relationship between units and mass can shift, which is why quoted conversion figures differ across sources and across decades.
For a purchaser the practical consequence is direct. A vial labelled in units carries a claim about activity that has to have been measured, and a supplier stating units without naming a method has made an assertion rather than a measurement.
How Many Milligrams Is 10000 Units?
For hcg peptide the honest answer is approximately one milligram, and the word approximately is doing real work.
Figures in the region of ten thousand units per milligram are commonly quoted for highly purified material, which puts a 10000 unit vial near a milligram.
That figure is not a conversion factor in the way a molecular weight is. It is an empirical property of a particular preparation.
A less pure preparation carries other protein alongside the hormone, so the same mass carries fewer units of activity.
A preparation with a different glycosylation profile can carry a different activity for the same protein content.
And the reference standard itself has changed more than once over the decades, which shifts the arithmetic for everyone calibrating against it.
What follows is that a research vial labelled in units and a research vial labelled in milligrams are not straightforwardly comparable, and converting between them by a remembered factor introduces an error nobody records.
The defensible position is to work in the units the material was supplied in, and to record which they were rather than converting.
Where a study genuinely needs a mass figure, the certificate should provide the protein content determination that gives it, rather than the calculation being done from a rule of thumb.
What Does the Heterodimer Structure Change?
Hcg peptide is two separate protein chains held together without a covalent bond, and that architecture creates a failure mode nothing else in this catalogue has.
The two subunits are made from different genes. One is shared across a family of related hormones and the other is unique to this one.
Neither subunit is active on its own. The receptor recognises the assembled pair. A preparation in which the pair has come apart is inactive, whatever its protein content.
Dissociation is promoted by the things that denature proteins generally: heat, extremes of pH, agitation, and repeated freezing and thawing.
That last one is worth emphasising, because freezing a solution is the reflex habit for preserving a peptide and it is the wrong move here.
A mass measurement will not detect dissociation, because the total protein present is unchanged. Only the arrangement has altered.
Size exclusion chromatography will detect it, since the dimer and the free subunits differ substantially in size.
A bioassay detects it directly, which is another argument for the unit-based system: activity is what dissociation destroys, so activity is what should be measured.
The practical instruction that follows is short. Do not freeze reconstituted material, do not shake it, and prepare what will be used rather than storing solution.
What Should the Certificate Show?
An hcg peptide certificate carries six fields, and they are not the fields a synthetic peptide certificate carries.
Assigned potency in units, with the method named and the reference standard identified against which that assignment was made, since a unit read against one standard is not the same unit read against another.
Protein content, by a stated determination. Without that figure no mass can be derived from the vial at all.
Purity, meaning the share of the protein present that is the intact heterodimer rather than free subunits or aggregate.
The determination used for that, which should be size exclusion chromatography or an equivalent method that separates by size.
Source and production route, since material of this kind is either purified from a biological source or produced recombinantly and the two are different articles.
Lot number and manufacturing date.
A certificate quoting units without naming a method has stated a number that cannot be checked, and on an article whose whole labelling system is built on a measurement that is a substantial omission.
Why Is It Not a Peptide?
Hcg peptide sits in this catalogue alongside synthetic peptides and belongs to a different class, which changes what can be verified about it.
A synthetic peptide is one chain of defined length, assembled residue by residue, with one exact mass calculable from the sequence.
This is two chains of over ninety and over one hundred and forty residues respectively, made biologically, associated without a covalent bond, and carrying attached carbohydrate at several sites.
That carbohydrate is heterogeneous. Different molecules in the same preparation carry different glycan structures at the same positions.
So intact mass is a distribution centred near 36 kDa rather than a number, and a certificate quoting an exact mass has quoted something the material does not have.
The methods that apply are protein methods. Electrophoresis establishes apparent size and shows fragments or aggregate as extra bands.
Size exclusion chromatography establishes whether the two subunits are still associated, which is the failure mode that matters most here.
An immunoassay establishes identity against antibodies raised to the molecule, and a bioassay establishes activity, which is what the labelling system is built on.
None of those is exotic and none of them appears on a certificate written to a synthetic peptide template.
A supplier offering a sequence, a calculated mass and a purity percentage for this article has supplied a document describing a different kind of thing entirely.
How Should the Vial Be Handled?
Handling hcg peptide follows protein rules rather than peptide rules, and the differences are consequential.
Sealed lyophilized material holds at 2 to 8 degrees Celsius, which is a warmer specification than most of this catalogue and is standard for this class.
Bring the vial to ambient temperature before opening and reconstitute gently, adding diluent down the wall and allowing it to stand rather than swirling vigorously.
Do not vortex and do not shake. A non-covalent dimer at an air-liquid interface comes apart, and the damage is not visible.
Do not freeze reconstituted material. Freeze-thaw is the most reliable way to destroy activity here. It is also the habit most researchers bring straight from peptide work.
Refrigerated storage of a reconstituted solution is appropriate for a short period, and the definition of short should come from the supplier rather than from assumption.
Bacteriostatic diluent is the sensible default for anything held more than a few hours, since an unpreserved protein solution at 4 degrees is a growth medium.
Use low-binding consumables. A protein at low concentration adsorbs, losing proportionally more than a small peptide would.
Record lot, the stated potency and its method, the diluent, the storage temperature and the date. A unit without a method is not a measurement.
Why does that field matter?
Two vials from different suppliers can both read 10000 units and have been calibrated against different standards by different assays.
Recording which one applied is what makes a later comparison meaningful.
There is a second reason to write the method down.
Suppliers change source material and reference standards get revised.
When that happens the number on the label can stay at 10000 while the article behind it has moved.
A record naming the assay and the standard makes that change visible in the data.
Without it, a shift in an hcg peptide preparation looks exactly like a shift in the biology under study, and no amount of later analysis separates the two.
That is a failure mode worth designing against.
Published Literature
Selected references on the structure and biology of this hormone and on the standardisation of its potency.
- Cole LA. Reproductive Biology and Endocrinology. 2009;7:8. DOI: 10.1186/1477-7827-7-8
- Birken S, Berger P, Bidart JM, Weber M, Bristow A, Norman R, et al. Clinical Chemistry. 2003;49(1):144-154. DOI: 10.1373/49.1.144
- Storring PL, Gaines Das RE. Journal of Endocrinology. 1989;123(2):275-293. DOI: 10.1677/joe.0.1230275
- Fournier T, Guibourdenche J, Evain-Brion D. Placenta. 2015;36 Suppl 1:S60-S65. DOI: 10.1016/j.placenta.2015.02.002
Frequently Asked Questions
What is an international unit?
A measure of biological activity defined by comparison against a reference preparation in a defined bioassay, expressed as a ratio and scaled by the units assigned to the standard.
Why is this compound sold that way?
Because a glycoprotein hormone carries variable attached carbohydrate, so a milligram of one batch is not chemically identical to a milligram of another and the activity varies with it.
How many milligrams is 10000 units?
Approximately one, and approximately is doing real work. Figures near ten thousand units per milligram are commonly quoted for highly purified material.
Is that a fixed conversion?
No. It is an empirical property of a particular preparation. Purity, glycosylation profile and the reference standard used for calibration all move that figure, sometimes by a wide margin.
So can units and milligrams be compared across suppliers?
Not straightforwardly. Converting by a remembered factor introduces an error nobody records. Work in the units supplied and record which they were.
What is the structure?
A heterodimer of two different protein chains made from different genes, held together without a covalent bond, at roughly 36 kDa with the carbohydrate included.
Is either subunit active alone?
No. The receptor recognises the assembled pair, so a preparation in which the pair has come apart is inactive regardless of how much protein it contains.
What causes them to come apart?
The things that denature proteins generally: heat, extremes of pH, agitation, and repeated freezing and thawing.
Can a mass measurement detect that?
No. The total protein present is unchanged. Size exclusion chromatography detects it, and a bioassay detects it directly.
What is the most common handling mistake?
Freezing reconstituted material. It is the reflex habit from peptide work and it is the most reliable way to destroy activity in this molecule.
What should the certificate state?
Assigned potency with the method and reference standard named, protein content by a stated determination, the share that is intact heterodimer, the method used to establish that, and the production route.
Why does the production route matter?
Material of this kind is either purified from a biological source or produced recombinantly, and the two are different articles with different impurity profiles.
Compliance Statement
HCG is sold exclusively for laboratory research use. It is not a drug, food, or cosmetic product, and it is not a dietary product of any kind. It is not approved by the FDA or any comparable authority for human or veterinary use, it is a glycoprotein hormone rather than a synthetic peptide and is labelled in international units which measure biological activity against a reference preparation rather than an amount of substance, the relationship between units and mass is not a constant and depends on the preparation and the standard used, approved formulations of this hormone exist but material supplied here is not one of them and is not manufactured to pharmaceutical standards, and no compound in this range is offered for any human or veterinary purpose. This product is not intended to diagnose, treat, cure, or prevent any disease. It must not be given to humans or animals. Purchase is restricted to qualified researchers and institutions operating within applicable laws. All handling is the responsibility of the purchasing laboratory.
Other formats of HCG
HCG is also stocked as HCG 5000iu, hMG (Menotropins) 150IU preloaded 3ml pen and HMG 75IU. Each listing states its own quantity and concentration, and the pen and vial comparison explains what changes between formats.
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