LESSON 2 OF 2
Repair, brain, reproduction, immunity, skin and energy
By the end you can
- Name the other main research areas
- Give one natural messenger and one product example for each
- Use the right research language for each area
Tissue repair
Repair research looks at how tissue heals: new blood vessels, cell movement and collagen. Thymosin beta-4 is a natural protein involved in cell movement. The full protein has been tested in human eye-drop trials; TB-500, a short fragment of it, has not. BPC-157 comes from a stomach protein. Most repair research so far is in animals.
Brain and nerves
Some peptides act on the nervous system. Semax is a modified fragment of ACTH, a pituitary hormone. Selank is based on tuftsin, an immune peptide. Both were developed in Russia. Others, like Dihexa and P-21, are early-stage lab compounds studied only in rodents.
Reproductive hormones
The reproductive system runs on a peptide chain much like the GH axis. Kisspeptin triggers GnRH, which tells the pituitary to release LH and FSH, the two hormones that signal the ovaries and testes. Gonadorelin copies GnRH, and HCG acts like LH. PT-141 and oxytocin act on brain pathways studied in social and sexual behavior.
Several of these molecules are approved drugs, but only as branded products: HCG (fertility drugs), oxytocin (Pitocin, used in labor) and PT-141 (bremelanotide, sold as Vyleesi). Gonadorelin was once FDA-approved and is now off the US market. Kisspeptin-10 has only small human studies, and FDA advisers voted against allowing pharmacies to compound it in 2024.
Immunity and skin
Thymosin alpha-1 comes from the thymus and is studied in immune signaling. LL-37 is the body's own antimicrobial peptide. In skin research, GHK-Cu is a natural copper peptide studied in collagen and wound models, and melanocortins, hormones such as α-MSH that signal skin cells to make pigment, are copied by MT-1 and MT-2.
Cellular energy and aging
Mitochondria are the cell's power plants. NAD+ is a coenzyme, a helper molecule cells need to make energy. MOTS-c and humanin are small peptides encoded in mitochondrial DNA. SS-31 (elamipretide) targets cardiolipin, a fat in the inner membrane of mitochondria; it received FDA accelerated approval, as Forzinity, for one rare disease. Bioregulators like Epithalon come from Russian aging research.
Together with metabolism and the growth hormone axis from Lesson 1, that makes eight research areas: metabolism, growth hormone, repair, brain, reproduction, immunity, skin and cellular energy.
Metabolic
- Natural
- GLP-1, GIP, amylin
- Examples
- Semaglutide, retatrutide
Growth hormone axis
- Natural
- GHRH, ghrelin
- Examples
- Ipamorelin, tesamorelin
Tissue repair
- Natural
- Thymosin beta-4
- Examples
- BPC-157, TB-500
Brain & nerves
- Natural
- ACTH, tuftsin
- Examples
- Semax, Selank
Reproductive
- Natural
- Kisspeptin, GnRH
- Examples
- Gonadorelin, HCG
Immune
- Natural
- Thymic peptides, LL-37
- Examples
- Thymosin alpha-1, LL-37
Skin & pigment
- Natural
- Copper peptide, α-MSH
- Examples
- GHK-Cu, MT-1
Energy & aging
- Natural
- NAD+, mitochondrial peptides
- Examples
- NAD+, MOTS-c, SS-31
Key terms
- Thymosin beta-4
- A natural protein involved in cell movement; TB-500 is a fragment of it.
- LH and FSH
- Pituitary hormones that signal the ovaries and testes.
- Melanocortin
- A family of hormones, including α-MSH, that act on pigment and other receptors.
- GnRH
- Gonadotropin-releasing hormone, the brain's signal for reproductive hormones.
- Antimicrobial peptide
- A peptide the immune system uses to fight microbes, like LL-37.
- Mitochondria
- Structures inside cells that produce energy.
- Bioregulator
- Short peptides from Russian research, each studied for a specific tissue.
Remember
- The catalog maps onto eight research areas.
- Each area has natural messengers that research peptides copy or modify.
- Many areas, especially repair and brain, rest mainly on animal research.
WATCH TO LEARN MORE
Endocrine System, Part 1: Glands & Hormones (Crash Course A&P #23)
CrashCourse · about 10 min
A fast, illustrated overview of the body's hormone glands and how chemical messengers coordinate many body systems.
From an outside channel, for background science. Partner rules still apply to everything you say. Watch on YouTube