Format
How it works
The physiology and mechanism behind the effect.
15 articles
Metabolic healthAdipotide — the peptide that kills fat blood vessels and why it's dangerousThere's a way of thinking about fat tissue that most people don't encounter in popular accounts of metabolism: white adipose tissue is not just a storage depot. It's a living, vascularized organ. It has its own blood supply, its own immune cell population, its own endocrine activity. It grows when you gain weight the way any tissue grows — by building the infrastructure to sustain itself, including new capillaries and venules that deliver oxygen and nutrients to the expanding mass. Fat tissue doesn't just accumulate; it recruits the resources it needs to survive.8 min readMetabolic healthAOD-9604 in plain English — what a growth hormone fragment actually doesYou've been doing the things. The training is consistent, the diet is reasonable, the processed food is largely gone, the sleep is better than it used to be. And there's still this: a layer of fat that sits at the lower abdomen, the hip-flank, the back of the arm, that does not move. Not noticeably. Not in any timeframe that the effort seems to justify. You're leaner than you were five years ago in most ways. In certain specific ways, nothing has changed at all.8 min readCognitive supportFGL (FG loop) — the NCAM-derived peptide for memoryThere is a moment in some people's experience of early cognitive decline — not the dramatic loss, but the earlier and stranger one — when the brain begins to feel like a place where connections don't quite hold. You reach for a thought and find the thought, but the thread that leads to the next thought, and the one after that, is loose. Not broken. Just not as taut as it used to be. It is a subtle wrongness, and it is easy to dismiss. Doctors, when you describe it, sometimes tell you that stress does this. They are not wrong. They are also not entirely right.8 min readGrowth hormone and recoveryFollistatin 344 — what the natural myostatin inhibitor actually doesThe bruise that won't heal. The workout that used to be maintenance and now leaves you wrecked for three days. The slow, unwelcome arithmetic of losing muscle mass even as you eat enough protein and train consistently. For some people these experiences arrive in their forties, for others earlier, and for people living with muscular dystrophy or other wasting diseases they arrive much sooner and with much higher stakes. The body has more than one mechanism for limiting muscle growth, and at the center of several of them is a protein your body already makes — one that was studied for its role in reproduction long before anyone thought about its connection to muscle.8 min readAnti-aging and cellular healthFOXO4-DRI — the senolytic peptide that started the conversationIn the spring of 2017, a paper appeared in the journal Cell that produced an unusual reaction in the longevity research community — a reaction that was part scientific excitement, part careful skepticism, and part something rarer in academic biology: the sense that a mechanism had been found that was genuinely elegant. The paper came from Peter de Keizer and colleagues at Erasmus University Medical Center in Rotterdam. The compound at the center of it was a synthetic peptide called FOXO4-DRI. The images that accompanied the paper — aged mice that had regrown their fur, restored their kidney function, run faster, recovered what looked like younger vitality after treatment — circulated widely online in a way that peer-reviewed biology papers almost never do.8 min readAnti-aging and cellular healthGHK-Cu in plain English — what copper-binding peptides actually doThree amino acids. One copper ion. A biological effect profile that touches wound healing, skin remodeling, gene expression, antioxidant defense, and inflammation — all from something small enough to have been hiding in plain sight in human blood plasma for the entirety of your life. GHK-Cu is not an exotic pharmaceutical engineered by a team of chemists targeting a specific receptor. It is a tripeptide your body has already been making, using, and declining to produce in adequate quantity as you age. Understanding what it actually does — not the marketing version, not the overpromised version, but the mechanistic version — requires starting with what those three amino acids are and why the copper matters.8 min readHormonal and endocrineHCG in plain English — what LH mimicry actually doesIn 1927, two scientists named Selmar Aschheim and Bernhard Zondek discovered that injecting urine from pregnant women into immature female mice caused ovarian development — something that shouldn't have happened in animals that hadn't yet reached sexual maturity. They had stumbled onto evidence of a powerful hormonal signal being excreted in pregnancy urine in large quantities. That signal turned out to be human chorionic gonadotropin, and for decades it was extracted from the urine of pregnant women and used as a pharmaceutical. The fact that it worked — and kept working across a remarkable range of clinical applications — suggested something important about its mechanism. HCG was not mimicking a signal that existed only in pregnancy. It was speaking a language the body's own endocrine receptors already understood fluently.4 min readWomen's hormonal healthHot flashes and night sweats — what's actually happening at the hypothalamic levelThe wave starts at the chest. Not pain, not quite — more like a pressure that turns into heat, spreading upward through the sternum and into the face before you have time to name what's happening. Your skin blooms red. The back of your neck dampens. You push the covers off and in four minutes it's over, leaving you cooled and clammy and awake at 2:47 in the morning. Then again at 4:11. During the day it arrives without warning in the middle of a sentence, and you pause, not because you've forgotten what you were saying, but because you are suddenly on fire and that seems like it should matter more than whatever you were saying. This is the vasomotor symptom — the hot flash, the night sweat, the thermoregulatory system misfiring in ways that disrupt sleep, concentration, work, and quality of life in patterns that are exhausting in proportion to how invisible they are to everyone around you.6 min readGrowth hormone and recoveryMK-677 in plain English — how oral GH secretagogues actually workYour stomach growls before lunch. You didn't think about being hungry, didn't decide to feel it — the signal arrived, unbidden, and suddenly food was the most important thing in the room. That signal has a name: ghrelin. And ghrelin does more than make you hungry. It is one of the primary switches that tells your brain to release growth hormone. MK-677 works because it found a way to press that switch without the rest of ghrelin's biology getting in the way.8 min readMitochondrial healthMOTS-c in plain English — mitochondrial-derived peptides explainedYour mitochondria are not quiet. They're not just burning fuel and staying out of the way. They're running a continuous metabolic read on the cell's energy state and broadcasting updates — and those updates, it turns out, include peptides that circulate through the body and communicate with tissues that have nothing to do with where the mitochondria physically sit. MOTS-c is one of those peptides. Understanding what it actually does requires starting with what the cell does when energy runs low.8 min readCognitive supportPinealon and the pineal gland — what a tripeptide bioregulator actually doesThere's a small organ buried deep in the center of your brain, roughly the size of a grain of rice, that Descartes called the seat of the soul. He was wrong about the metaphysics but not entirely wrong about the importance. The pineal gland sits at the junction of the two cerebral hemispheres, receives information about light through a neural pathway from the retina, and uses that information to synthesize and secrete melatonin — the hormone that tells the rest of your biology what time of day it is, what time of year it is, and when to shift into the physiological mode that sleep and cellular repair require. It is, in a meaningful sense, the body's master clock signal.7 min readSexual healthPT-141 in plain English — how a brain melanocortin agonist became a libido drugYou're not in the mood. Not because anything is wrong, exactly. Not because of a fight, or exhaustion, or a specific stressor you can name. Just — absent. The interest isn't there. And the absence is its own kind of problem, because desire isn't something you can manufacture by deciding to want it. You can go through the motions. You can create conditions. But the signal either arrives or it doesn't, and if it doesn't, nothing downstream can substitute for it.8 min readMetabolic healthRetatrutide in plain English — the triple agonist that may eclipse tirzepatideYou've been on tirzepatide for six months. The first three were dramatic — ten pounds the first month, then eight, then seven. The nausea became manageable. The appetite that had organized your life for decades became something you could ignore for hours at a time. And then, somewhere around month four or five, the number on the scale stopped moving. Not reversed. Not stalled terribly. Just plateaued at a point that isn't where you were hoping to be. Your prescribing provider says this is expected. The dose is at its maximum. Your body has found a new equilibrium.8 min readMetabolic healthTesamorelin in plain English — the GHRH analog FDA-approved for visceral fatYou can be technically lean and still have a problem with visceral fat. The number on the scale cooperates. The waist measurement doesn't. You eat carefully, you exercise — the subcutaneous fat over your hips and thighs shifts over years of work, but the deep abdominal fat, the kind that sits around your organs and shows up on imaging as a dense metabolically active mass, seems almost indifferent to everything you do. Your provider's answer, if you're lucky, is "keep up the good work." If you're less lucky, it's a referral to a nutritionist who tells you to eat more fiber.6 min readImmune modulationThymosin Alpha-1 in plain English — what immune modulation actually meansYour immune system is not a weapon pointed outward. It's a negotiation happening continuously, in every tissue, between cells that have learned to recognize self from non-self, and between signals that say "more" and signals that say "stop." When the negotiation goes wrong in one direction, you get chronic infection — the immune system can't mount a sufficient response to clear a pathogen, and the pathogen persists. When it goes wrong in the other direction, you get autoimmunity — the immune system mounts a response against the body's own tissue, having lost the ability to tell the difference. Both failure modes are, in a meaningful sense, the same problem: a loss of calibration. The question is what calibration actually requires.8 min read