RESEARCH HUB · REPRODUCTIVE ENDOCRINOLOGY
Fertility & HPG-Axis Research
hCG, hMG and kisspeptin explained from the published literature: how the brain–pituitary–testis loop controls testosterone and sperm production, what clinical studies measured, and how fertility clinics use gonadotropins.
5 deep dives · 30 min of reading · research use only
In 60 seconds
The hypothalamus (GnRH) drives the pituitary (LH, FSH), which drives the testes or ovaries. External testosterone switches the loop down and lowers sperm production. hCG stands in for LH and hMG adds FSH, which is why clinics use them to keep or restore fertility under monitoring.
- LH drives testosterone; FSH drives sperm and follicle development.
- External testosterone suppresses both and lowers intratesticular testosterone.
- Fertility treatment belongs with a fertility clinic.
Trying to conceive? Start with a fertility clinic.
A fertility clinic or endocrinologist tests properly — semen analysis against WHO reference ranges, LH, FSH, testosterone and oestradiol — and prescribes registered medicines under monitoring. This hub explains the science; it is not a treatment guide and gives no dosing.
DEEP DIVES
hCG and Spermatogenesis: What the Research Measured
hCG mimics LH, the hormone that tells the testes to make testosterone. Here is what clinical studies measured when men were given it: intratesticular testosterone, sperm counts, motility and time to conception.
7 min read · Read →hMG vs hCG: Gonadotropins Explained
Two gonadotropin preparations, two different jobs. hCG carries an LH-like signal; hMG carries FSH as well. Here is what that difference means and what the IVF meta-analyses found.
6 min read · Read →How Fertility Clinics Use Gonadotropins
A plain-language map of where gonadotropins sit in clinical fertility care: ovarian stimulation, the trigger shot, and restoring sperm production in men. Context, not instructions.
6 min read · Read →Kisspeptin and the HPG Axis
Kisspeptin sits at the very top of the reproductive axis. Discovered as the missing link behind puberty, it switches on the GnRH neurons that set every downstream hormone in motion.
5 min read · Read →The HPG Axis Explained: Testosterone, LH and FSH
The hypothalamic–pituitary–gonadal axis is the feedback loop behind testosterone and fertility. Understanding it explains why hormone therapy, sperm production and blood tests behave the way they do.
6 min read · Read →COMPOUND PROFILES
hCG (Human Chorionic Gonadotropin)
A placental glycoprotein hormone that mimics luteinising hormone (LH), stimulating testicular testosterone production — a prescription fertility medicine.
hMG (Human Menopausal Gonadotropin)
A gonadotropin preparation purified from urine that carries both FSH and LH activity, used in assisted reproduction.
Kisspeptin-10
The shortest active fragment of kisspeptin, the hypothalamic peptide that triggers GnRH release and sits at the top of the reproductive axis.
Oxytocin
The hypothalamic nonapeptide hormone of labour and lactation, and a major research focus in social behaviour.
COMPARE
KEY TERMS
- Luteinising Hormone (LH)
- The pituitary hormone that tells the testes to make testosterone and triggers ovulation in women.
- Follicle-Stimulating Hormone (FSH)
- The pituitary hormone that grows ovarian follicles and supports sperm development in the testes.
- HPG Axis (Hypothalamic–Pituitary–Gonadal Axis)
- The hormone loop from hypothalamus (GnRH) to pituitary (LH, FSH) to gonads (testosterone, oestradiol, sperm or eggs).
- Spermatogenesis
- The roughly three-month process by which the testes produce mature sperm, driven by FSH and high testosterone inside the testes.
- Semen Parameters
- The measured features of a semen sample: volume, concentration, total count, motility and morphology, read against WHO reference ranges.
- International Unit (IU)
- A measure of biological activity; on a research syringe the "units" scale is a convenient volume marker, not a mass.
FREQUENTLY ASKED
What is the HPG axis?
The hypothalamic–pituitary–gonadal axis. The hypothalamus releases GnRH, the pituitary answers with LH and FSH, and the testes or ovaries make testosterone, oestradiol and sperm or eggs. Hormones from the gonads feed back to regulate the whole loop.
How do hCG and hMG differ?
hCG acts on the LH receptor only. hMG carries FSH as well as LH activity. FSH is what grows ovarian follicles and supports the later stages of sperm production.
Do you provide fertility treatment or advice?
No. This hub summarises published research. Fertility treatment is prescribed and monitored by a fertility clinic or endocrinologist, after semen analysis and hormone blood tests.
Are these compounds sold for human use?
No. Any compound listed by Living Water Labs is supplied strictly for laboratory research purposes. Nothing on this site is medical advice or a dosing guide.
Educational content, not medical advice. All products are supplied for laboratory research purposes only and are not for human or veterinary use.