What Is Actually Inside Placenta Extract?
The chemistry behind Laennec, Melsmon and the idea of a “regenerative” injection
There is something slightly strange about the phrase “placenta injection”.
It makes it sound as though someone has taken a placenta, put it in a bottle and decided that this is probably good for you.
Obviously, that isn't what is happening.
Laennec and Melsmon are manufactured pharmaceutical preparations made from human placental tissue. The placenta is processed, broken down and purified, leaving behind a complex mixture of smaller biological components.
And that is where things get interesting.
Because once you start looking at what is actually left in the ampoule, the word placenta becomes almost meaningless on its own.
A placenta is not one ingredient
The placenta is an extraordinarily complicated piece of biology.
During pregnancy it acts as an interface between mother and fetus, but it is also an endocrine and metabolically active organ. It produces hormones, growth-related signals and many other biological molecules.
A placental extract, however, isn't simply a concentrated version of all of those things.
The manufacturing process changes the material.
The tissue is processed, hydrolysed and purified, and many of the original large molecules are broken down into smaller components.
A 2025 review comparing human placental extracts makes this point particularly clearly: different products can have substantially different compositions depending on the source tissue, the part of the placenta used and the manufacturing method.
Read the 2025 review on human placental extracts
So the interesting question isn't simply:
What's in placenta?
It is:
What's left in this particular placenta extract?
Melsmon is mostly a low-molecular-weight mixture
Melsmon is made using hydrochloric-acid hydrolysis.
The manufacturing process begins with screened human term placenta. The umbilical cord is removed and the placental villous tissue is processed to remove blood before being extracted and purified using hydrochloric acid.
The pH is then adjusted and benzyl alcohol is added before the final preparation is sterilised.
The resulting preparation contains a mixture of amino acids and other low-molecular-weight substances.
One analysis reported 16 amino acids in Melsmon, including glutamic acid, aspartic acid, leucine, glycine, arginine, alanine and lysine.
There are also reported carbohydrate-related components and fatty acids.
That sounds rather less glamorous than “placenta”.
But this is the interesting part.
The injection isn't relying on some mysterious intact placenta molecule floating around in the ampoule.
It is a mixture of biological building blocks and other extracted compounds produced by the manufacturing process.
Laennec is a little different
Laennec also undergoes hydrolysis, but its manufacturing process is different.
The placenta is refrigerated, washed and dissected before being homogenised, defatted and dried. The material is then treated with hydrochloric acid and digested with pepsin before further hydrolysis and purification.
Read the manufacturing comparison
The 2025 review notes that hydrochloric-acid hydrolysis tends to produce more low-molecular-weight components, while protease-based processing can leave relatively higher-molecular-weight peptides.
In other words:
how you make the extract changes what you end up injecting.
They may come from the same biological source, but the chemistry isn't identical.
What has actually been identified in Laennec?
Laennec has been analysed for decades.
Older studies identified a range of amino acids, including glutamic acid, aspartic acid, glycine, alanine, leucine, serine and threonine.
But modern analytical techniques have allowed researchers to go much further.
A 2023 proteomic study used mass spectrometry to identify 41 peptides in Laennec, each consisting of four to eight amino-acid residues.
Read the peptide analysis of Laennec
The researchers then used bioinformatic analysis to investigate possible biological targets of those peptides.
Among the pathways identified were proteins involved in apoptosis, MAP kinase signalling and the AKT/GSK3B/MTOR pathway.
That sounds incredibly impressive.
And this is where we need to slow down.
The final composition depends partly on how the placenta is processed. The 2025 review describes substantial differences in manufacturing methods and composition between human placental extracts, including Laennec and Melsmon.
Adapted from Alimu et al., 2025. Read the full review.
Finding peptides and identifying possible biological targets is interesting.
It isn't the same as proving what those peptides do after an injection in a human.
And this is where the “regeneration” language comes from
Placental extracts have been associated with a surprisingly wide range of biological effects in laboratory and animal research.
The 2025 review describes reported antioxidant, anti-inflammatory and immunomodulatory effects, alongside research involving cell proliferation, tissue repair and wound healing.
Read the review of biological effects
There are also studies investigating specific effects of placental extract on skin biology.
A 2022 Scientific Reports study found increased expression of genes including COL1A1, ELN and HAS2 in cultured human dermal fibroblasts exposed to human placental extract.
This gives us a plausible biological explanation for why placental extracts keep appearing in conversations about collagen and skin quality.
But the experiment happened in cultured cells.
It doesn't prove that an injection produces the same response in human facial skin.
That distinction comes up repeatedly with these products:
interesting mechanism ≠ proven clinical outcome.
What about growth factors?
This is where things can get particularly confusing.
Because the placenta naturally produces many growth factors, hormones and signalling molecules, it is tempting to assume that a placental extract must simply contain large amounts of all of them.
It isn't that straightforward.
The extraction process can break down proteins and alter the final composition. Some larger molecules may be degraded, while smaller peptides, amino acids and other compounds remain.
A review examining the translation of human placental extracts into clinical practice has pointed out that the exact composition of these preparations depends heavily on the extraction and hydrolysis process.
Read the review on human placental extract and clinical translation
So when someone says:
“Placenta contains growth factors.”
the scientifically useful follow-up question is:
Which growth factors are actually present in this finished product, at what concentration, and are they still biologically active after processing?
Those are much harder questions.
There aren't actually stem cells floating around in the ampoule
This is another misconception worth clearing up.
Human placental extracts are sometimes described online using language that makes them sound like a kind of stem-cell treatment.
They aren't.
The extraction and sterilisation processes remove viable cells. What remains is an extract containing molecules and molecular fragments derived from the original tissue.
A review specifically discussing the translation of human placental extracts into clinical practice notes that cellular hydrolysis eliminates viable placental cells while leaving behind various extracellular-matrix components and smaller biological molecules.
So Laennec isn't injecting living placental stem cells into your skin.
And that distinction matters.
Then what is the body actually receiving?
This is probably the simplest way I can describe it.
The body isn't receiving a little piece of placenta.
It is receiving the processed chemical aftermath of placenta: a complex mixture of amino acids, peptides and other low-molecular-weight substances, depending on the product and how it was manufactured.
Some of these molecules may act as substrates, while others may interact with receptors and signalling pathways.
Some have been investigated in relation to inflammation and oxidative stress, while others may have biological effects that we still don't fully understand.
And some will simply be broken down and cleared by the body.
Not every molecule in a biological extract needs to have a dramatic biological effect.
Laennec and Melsmon aren't interchangeable
At first glance, both are simply “human placenta injections”.
Look underneath the label, however, and the differences start to accumulate: different manufacturing processes, different hydrolysis methods, different concentrations, different chemical profiles, different approved indications and different research histories.
The 2025 review makes this point particularly clearly. Even extracts made from the same biological source can have different compositions and biological effects depending on how they are manufactured.
That is a much more interesting way of thinking about placenta medicine than asking which brand is “stronger”.
The more useful question is what is actually in the preparation, how it got there, and what evidence exists for what it does.
And then there is the problem of the word “active”
With a conventional drug, we often have a satisfying story: one molecule, one target, one receptor, one pathway.
Placental extracts don't necessarily behave like that.
They are mixtures, and those mixtures can contain multiple components acting through different biological pathways at the same time.
That makes them difficult to study, but it also makes them difficult to describe accurately.
Saying “this is a complex mixture of peptides and low-molecular-weight compounds whose biological activity is still being characterised” doesn't fit very neatly on an Instagram post.
“Regenerative placenta injection” does.
So what might actually be doing the work?
The honest answer is that we don't know yet.
Researchers have identified amino acids and peptides, observed changes in gene expression, and investigated effects involving fibroblasts, inflammatory signalling and oxidative stress.
What remains much less certain is the complete relationship between composition, mechanism and clinical outcome.
The 2025 review concludes that the chemical composition of human placental extracts remains incompletely characterised and that many potentially active components and mechanisms have yet to be identified.
So the story isn't “we know exactly what Laennec does.”
It is closer to:
we can see pieces of the biological story, but we haven't finished putting them together.
There is even newer evidence that the biological effects may extend beyond skin.
A 2026 study investigated Melsmon in a stress-sensitive mouse model and found reductions in stress-induced neuroinflammation and peripheral inflammation. The researchers also observed effects on pathways involved in the body's stress response, although they could not identify the specific components of Melsmon responsible for those effects.
But this is still animal research, and we don't know which components are responsible for which effects or how those findings translate into human clinical outcomes.
The strange appeal of a biological mixture
Perhaps this is part of the reason placenta has survived as a medical idea for so long.
It isn't a single fashionable molecule that appeared because somebody discovered it last Tuesday.
It is an extraordinarily complicated biological material that researchers have been trying to understand for decades.
Some of the claims surrounding it have travelled considerably further than the evidence.
But underneath all of that marketing is a genuinely interesting scientific question:
Can a complex biological extract influence the environment in which human cells repair, survive and function?
We don't have a complete answer yet, but we are getting better at asking the question.
And now, when I look at my little collection of amber ampoules, I see something slightly different.
Not magic.
Not stem cells.
Not a miracle.
Just a very complicated biological mixture that we are still learning how to understand.
Which, somehow, makes my emotional support stash feel a little more scientifically respectable.
C·🌷
Research notes
Human placental extracts
Biological effects of human placental extracts: variations in manufacturing methods and compositions.
Read the full review
Laennec peptide composition
The molecular mechanisms of the effect of standardized placental hydrolysate peptides on mitochondria functioning.
Read the study
Melsmon and stress-induced inflammation
2026
Effects of Melsmon on stress-induced neuroinflammation and peripheral inflammation.
Read the full study
Human placental extract and skin biology
Chang et al., 2022
Human placental extract activates a wide array of gene expressions related to skin functions.
Read the full study
Human placental extract and clinical translation
Human placental extract: the feasibility of translation from basic science into clinical practice.
Read the review
Laennec
Japan Bio Products
Official product information and composition.
Read the manufacturer information
Melsmon
Melsmon Pharmaceutical Co., Ltd.
Official medical information and composition.
Read the manufacturer information