HGH is produced naturally by the pituitary gland and commercially through recombinant DNA technology. Learn how HGH is made and how rhGH differs.
Human growth hormone (HGH, also called somatropin) is produced in two very different ways. The pituitary gland makes it naturally in pulses every day, while pharmaceutical HGH is produced in laboratories using recombinant DNA technology, with engineered cells that carry the human growth hormone gene. Both routes end in the same 191-amino-acid protein, but the manufacturing methods, purity standards, and regulations are worlds apart.
How the Body Produces HGH Naturally
Natural HGH comes from somatotroph cells in the anterior pituitary gland, a pea-sized structure at the base of the brain. The hypothalamus controls the process with two opposing signals: growth hormone-releasing hormone (GHRH) turns production on, and somatostatin turns it off.
Release is pulsatile rather than steady. Levels can rise sharply and fall back within a few hours.
- Sleep: the largest pulse of the day usually arrives during deep, slow-wave sleep.
- Exercise: intense activity, especially resistance training, triggers a temporary spike.
- Nutrition and stress: fasting, low blood sugar, and physical stress raise output; high blood sugar and obesity tend to lower it.
- Age: secretion peaks during puberty and declines gradually from roughly age 30 onward.
Because natural release is pulsatile, a single random blood draw tells a clinician very little. Doctors usually measure IGF-1 or run stimulation tests instead. HGH produced inside the body is also called endogenous HGH, which distinguishes it from the injected, pharmaceutical form.
How HGH Is Made in a Laboratory
The short answer to how is hgh made outside the human body is recombinant DNA technology. Scientists copy the human growth hormone gene and insert it into host cells that then act as living factories.
- Gene synthesis and vector insertion. The GH1 gene sequence is synthesized or copied and spliced into a circular DNA vector called a plasmid.
- Host cell transformation. The plasmid is introduced into bacterial cells such as E. coli or mammalian cells such as Chinese hamster ovary (CHO) cells.
- Fermentation or cell culture. The engineered cells multiply in controlled bioreactors filled with nutrient media.
- Harvest and purification. Cells are disrupted (bacteria) or the secreted protein is collected from the media (mammalian cells), then purified with chromatography to remove host proteins and DNA.
- Refolding and formulation. Bacterial product must be refolded into its correct three-dimensional shape. The protein is then stabilized with buffers and excipients.
- Lyophilization. Most injectable somatropin is freeze-dried into a powder and shipped with a separate diluent.
Recombinant production replaced an earlier method that extracted HGH from cadaver pituitary glands. That practice ended in 1985 after it was linked to Creutzfeldt-Jakob disease, a fatal brain disorder.
Bacterial vs. Mammalian Production
| Feature | E. coli (bacterial) | CHO (mammalian) |
|---|---|---|
| Product location | Inside the cell | Secreted into culture media |
| Folding | Requires refolding steps | Folds naturally |
| Cost | Lower | Higher |
| Typical use | Economical somatropin products | Most modern brand-name products |
rhGH vs. HGH: What's the Difference?
RhGH stands for recombinant human growth hormone. It is the pharmaceutical version of the hormone, sometimes called exogenous HGH because it comes from outside the body. The amino acid sequence is identical to natural HGH, but the delivery pattern is not.
| Feature | Endogenous HGH | Recombinant HGH (rhGH) |
|---|---|---|
| Source | Pituitary gland | Engineered cells in a bioreactor |
| Structure | 191 amino acids | 191 amino acids |
| Release pattern | Pulsatile, many times per day | One injected dose |
| Delivery | Into the bloodstream | Subcutaneous injection |
| Regulation | Body's own feedback loop | Prescription drug, Schedule III controlled substance |
Early versions of recombinant HGH contained 192 amino acids and frequently triggered antibody responses. Modern somatropin is a 191-amino-acid protein that matches the natural sequence.
The same general logic explains how is bpc 157 made, although BPC-157 is usually built by solid-phase peptide synthesis rather than recombinant cell culture.
Storage and Handling After Production
Lyophilized somatropin is generally stable when refrigerated and protected from light. After it is mixed with a diluent, stability drops quickly and the product must be handled according to its label.
Most reconstitution uses bacteriostatic water. Patients often ask how long is bac water good for; manufacturer labeling for bacteriostatic water typically states a 28-day beyond-use period after the first puncture. Storage rules vary by product, and people ask the same question in other categories, such as how long is lipo c good for with lipotropic injections.
Safety, Legal Status, and Clinical Use
In the United States, recombinant HGH is FDA-approved for a limited set of conditions, including pediatric growth hormone deficiency, adult growth hormone deficiency, Turner syndrome, Prader-Willi syndrome, and wasting associated with HIV.
Outside those indications, distributing or possessing HGH for performance or anti-aging purposes is illegal, and the drug is classified as a Schedule III controlled substance. Reported side effects include joint pain, swelling, carpal tunnel symptoms, and elevated blood sugar.
HGH is a prescription hormone, not a supplement. Anyone considering it should talk with a licensed healthcare professional rather than buying from an unverified source.
Frequently Asked Questions
How is HGH produced in the human body?
The anterior pituitary gland releases HGH in pulses controlled by the hypothalamus, which uses growth hormone-releasing hormone to stimulate production and somatostatin to suppress it. Output peaks during deep sleep and after intense exercise, and it declines gradually with age. Because levels swing widely, doctors usually check IGF-1 or order stimulation testing rather than a single random HGH blood draw.
Is synthetic HGH the same as natural HGH?
Recombinant HGH has the same 191-amino-acid sequence as the hormone your pituitary gland makes, so the protein itself is essentially identical. The difference is timing: natural HGH is released in many small pulses, while injected HGH arrives as one larger dose. Injected HGH is also a prescription, Schedule III controlled substance rather than something the body regulates on its own.
Is HGH still made from human cadavers?
No. Cadaver-derived HGH was discontinued in 1985 after it was linked to Creutzfeldt-Jakob disease, a fatal neurodegenerative disorder. Every legitimate HGH product on the market today is made through recombinant DNA technology in bacterial or mammalian cell cultures. Products sold as "cadaver HGH" or "pituitary HGH" online are not legitimate pharmaceutical products.
This page provides educational research information and does not replace medical advice, diagnosis, or treatment.