Description
PrymaLab · Research Use Only
HMG 75IU
The second number on the label is mostly measuring a different hormone
Read an hmg peptide label and you get two numbers that look symmetrical: 75 units of FSH activity, 75 units of LH activity. The first one means what it appears to mean. The second one is stranger, because a large share of the LH-receptor activity in this preparation is not produced by LH at all.
Specification Table
| Property | Value |
|---|---|
| Article | Human menopausal gonadotropin, also called menotropin |
| Article class | A biologically sourced preparation. Not a synthetic peptide |
| Source | Urine of postmenopausal donors |
| Declared content | 75 international units of FSH activity and 75 of LH activity |
| How units are assigned | By bioassay in an animal system against a reference preparation |
| Source of the FSH activity | FSH |
| Source of the LH activity | Largely hCG, concentrated during purification from the same urine |
| Why hCG dominates | It has a much longer half life than LH, so it carries more in vivo activity per unit mass |
| Reported share | Around 95 percent of in vivo LH-receptor bioactivity attributed to hCG |
| Consequence | A vial declaring LH activity is not a vial of LH |
| Other constituents | Other urinary proteins are present. Purification reduces them rather than removing them |
| Batch character | A preparation rather than a substance. Composition varies between lots |
| Vial | 75IU lyophilised |
| Storage | Sealed at 2 to 8°C. Do not freeze reconstituted solution and do not agitate |
What Does an HMG Peptide Label Declare?
An hmg peptide label declares two activities, each in international units, each assigned by bioassay rather than by weighing.
An international unit is not an amount of substance. It is a measure of biological effect against a reference preparation, and the hCG page in this catalogue works through why that distinction changes how a vial has to be handled.
The point specific to this article is what sits behind the second of the two numbers.
FSH activity comes from FSH, which is the straightforward half of the label.
LH activity is measured by what the preparation does at the LH receptor, and hCG acts at the same receptor. Human chorionic gonadotropin is present in postmenopausal urine and it gets concentrated along with everything else during purification.
Because hCG has a considerably longer half life than LH, it contributes far more in vivo activity per unit of mass, and the reported share of LH-receptor bioactivity attributable to hCG in these preparations sits around 95 percent.
So the number on the label is honest about what it measures and misleading about what produces it. It says LH activity, not LH content, and those are different claims.
Why Does That Distinction Matter Experimentally?
Because the two hormones behind an hmg peptide LH figure are not interchangeable at the receptor even though both engage it.
They differ in half life by a wide margin, which changes the shape of receptor exposure over time rather than only its magnitude.
They also differ in their beta subunits. The extended carboxy-terminal peptide on hCG is part of why it persists.
A design that assumes it is delivering LH, and reads its result as an LH effect, has assumed something the preparation does not support.
The honest framing is that this article delivers LH-receptor activity from a mixed source, with a defined total and an undefined split.
If the question genuinely concerns LH specifically, a recombinant LH preparation answers it and this one does not.
If the question concerns FSH with LH-receptor activity present, this is the article that matches, and the fact that the activity comes largely from hCG may not matter at all.
Which of those applies is the researcher decision that this page exists to inform.
What Kind of Article Is a Urinary Preparation?
An hmg peptide vial holds a preparation, not a substance, and the same distinction the thymalin page in this catalogue draws for a tissue extract applies here.
The starting material is donor urine, collected and pooled. Purification concentrates the gonadotropins and reduces everything else without eliminating it.
Compositional analyses of menotropin preparations have identified a range of other urinary proteins present as impurities, which is expected for a biologically sourced article and is not a manufacturing failure.
Two practical consequences follow.
First, lot number is part of the material description rather than a bookkeeping field. Two lots are two preparations that resemble one another rather than two portions of one thing.
Second, a purity percentage is not the right measurement. What can be established is the assigned activity for each of the two, the methods behind those assignments, and the profile of what else is present.
Highly purified versions of this article exist and reduce the non-gonadotropin content substantially. Which one is in a given vial is a certificate question, not a label question.
What Should the Certificate Show?
On an hmg peptide certificate, assigned FSH activity and assigned LH activity, each with the bioassay named and the reference preparation identified.
A statement on the source of the LH activity, meaning whether hCG content was measured and what it was.
Protein content by a stated determination, which is what allows any mass figure to be derived.
The purification grade. Highly purified and conventional preparations are different articles.
Non-gonadotropin protein content, or at least a statement that it was assessed.
Source and donor population, named rather than implied.
Lot number and manufacturing date.
The hCG line is the one that will be missing, and it is the one that decides whether the second number on the label means what a reader assumes.
How Does This Compare With Recombinant Preparations?
Recombinant FSH and recombinant LH are made in cell culture from defined constructs. They are substances in a way this article is not.
Three differences matter for a study design.
A recombinant preparation contains one hormone, so an experiment using it can attribute an effect to that hormone. This one contains two activities from at least three protein sources.
A recombinant preparation can be filled by mass with the activity stated for information, while a urinary preparation is filled to an activity because the mass is not the thing being controlled.
A recombinant preparation is consistent between lots to a degree a urinary one cannot be, since the starting material is a bioreactor rather than a donor pool.
None of that makes the urinary article inferior for every purpose, and I want to be careful here because the recombinant-is-better framing gets applied too broadly.
The urinary preparation delivers FSH activity alongside LH-receptor activity in a fixed relationship, and for questions where that combination is the thing being studied, splitting it into two recombinant components changes the article rather than purifying it.
Where it is clearly the wrong choice is any design that needs to vary the two activities independently, or that needs to attribute an effect to LH specifically rather than to LH-receptor engagement.
The choice is therefore a design question rather than a quality question, and framing it as quality is the mistake I see most often in how these two articles get compared.
Why Is It Sourced From Urine?
Because that was the only practical source when the preparation was developed, and the manufacturing base outlasted the reason.
Gonadotropins are glycoproteins. They cannot be made on a peptide synthesiser.
Postmenopausal urine carries high gonadotropin concentrations for straightforward endocrine reasons, so it became the raw material, collected in volume and processed industrially.
That is a genuinely unusual supply chain and it is still running, decades after recombinant alternatives arrived.
The reasons it persisted are partly cost, partly regulatory inertia around approved articles, and partly that the mixed activity profile turned out to be wanted rather than merely tolerated.
For a research buyer the consequence is simple. The source determines the composition, and the composition includes things nobody put there deliberately.
It also means the article carries a donor-derived origin, with the screening and traceability questions that come with any human-sourced material, and a certificate should say something about both.
None of that is a reason to avoid it. It is a reason to know what kind of thing is in the vial before designing around it.
The scale of the collection is worth a sentence because it explains the price and the batch structure.
Producing meaningful quantities of gonadotropin from urine requires very large volumes of starting material, pooled from many donors, which is why lots are large and why the donor pool is a population rather than a person.
Pooling helps consistency and it also means the composition of any lot is an average of whatever the donors happened to be excreting.
That average is stable enough to standardise against a reference preparation and it is not stable enough to call the article a substance.
How Should the Vial Be Handled?
Glycoprotein rules apply to hmg peptide handling, which puts it closer to the hCG page in this catalogue than to anything synthetic.
Sealed lyophilised material holds at 2 to 8 degrees Celsius, which is warmer than most of this range and is standard for this class.
Bring the vial to ambient temperature before opening, then reconstitute gently by running the diluent down the wall.
Do not vortex and do not shake. These are non-covalently associated heterodimers, and an air-liquid interface pulls the two subunits apart from one another.
Reconstituted solution stays refrigerated and never goes into a freezer.
Use bacteriostatic diluent 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 glycoprotein at low concentration adsorbs more than a small peptide does.
Record lot, both assigned activities with their methods, the reference preparation, the diluent, the storage temperature and the date.
Recording the reference preparation matters because two vials both declaring 75 IU may have been calibrated against different standards, and that difference cannot be reconstructed once the paperwork is separated from the vial.
Published Literature
Selected references on the composition of urinary menotropin preparations, on the purified forms and on peptide and protein storage generally.
- Bassett RM, Driebergen R. Reproductive BioMedicine Online. 2005;10(2):169-177. PMID: 14680547
- Keating GM. Drugs. 2018;78(15):1595-1604. PMID: 30264288
- Storring PL, Gaines Das RE. Journal of Endocrinology. 1989;123(2):275-293. DOI: 10.1677/joe.0.1230275
- Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Pharmaceutical Research. 2010;27(4):544-575. DOI: 10.1007/s11095-009-0045-6
Frequently Asked Questions
What is HMG?
Hmg peptide is short for human menopausal gonadotropin, also called menotropin. It is purified from the urine of postmenopausal donors.
What does the label declare?
Two activities, each in international units: 75 of FSH activity and 75 of LH activity. Both are assigned by bioassay rather than by weighing.
Where does the LH activity come from?
Largely from hCG. That hormone is present in the same urine and gets concentrated during purification. hCG acts at the LH receptor, so it registers as LH activity.
Why does hCG dominate the measurement?
It has a considerably longer half life than LH, so it contributes far more in vivo activity per unit of mass. Reported figures put its share around 95 percent.
Is the label wrong then?
No. It says LH activity, which is what was measured. It does not say LH content, and readers routinely read those as the same claim.
Why does the difference matter?
Because LH and hCG differ in half life by a wide margin, which changes the shape of receptor exposure over time rather than only its size.
What if a study needs LH specifically?
A recombinant LH preparation answers that question and this article does not. This one delivers LH-receptor activity from a mixed source.
When is this the right article?
When the question involves FSH with LH-receptor activity present, and the source of that activity is not itself the variable of interest.
Is it a defined substance?
No. It is a preparation from a biological source, so lot number is part of the material description rather than a bookkeeping field.
Are other proteins present?
Yes. Compositional analyses of menotropin preparations have identified a range of other urinary proteins. Purification reduces them rather than removing them.
Does a purity percentage apply?
Not usefully. What can be established is the assigned activity for each hormone, the methods behind those assignments and the profile of what else is present.
What is the one field most likely to be missing?
Whether hCG content was measured and what it was. That figure decides whether the second number on the label means what a reader assumes.
Compliance Statement
HMG 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 preparation purified from a biological source rather than a defined substance and its composition varies between lots, the LH activity declared on the label derives largely from chorionic gonadotropin concentrated from the same source rather than from luteinising hormone and the two are not interchangeable at the receptor, international units describe biological activity against a reference preparation rather than an amount of substance, and no article 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 HMG
HMG is also stocked as hMG (Menotropins) 150IU preloaded 3ml pen, HCG 5000iu and HCG 10000iu. Each listing states its own quantity and concentration, and the pen and vial comparison explains what changes between formats.
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