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Reference

The words on your prescription, in plain English.

Every term a clinician, a pharmacy label, or an article on this site might use - defined once, carefully, without marketing language. If a definition here ever conflicts with what your own clinician tells you, follow your clinician.

Weight management Pharmacy & compounding Healthy aging Sexual health Hair loss Care & coverage

Weight management

The vocabulary of GLP-1 care - what the molecules are, what they act on, and what the dosing words mean.

GLP-1

Glucagon-like peptide-1

A hormone your small intestine releases after you eat. It signals the pancreas about insulin, slows how quickly the stomach empties, and acts on brain regions involved in appetite. Medications described as GLP-1 receptor agonists are built to bind that same receptor.

GLP-1 receptor agonist

Agonist, GLP-1 RA

A medicine shaped closely enough to GLP-1 to activate its receptor. Semaglutide is one. "Agonist" simply means it switches the receptor on rather than blocking it.

GIP

Glucose-dependent insulinotropic polypeptide

A second gut hormone released with food, acting on a different receptor than GLP-1. Tirzepatide activates both GIP and GLP-1 receptors, which is why it is called a dual agonist.

Dual agonist

Twincretin

A molecule that activates two different receptors. Tirzepatide is the example in weight care - GIP and GLP-1 together.

Semaglutide

A GLP-1 receptor agonist. It is the active ingredient in certain FDA-approved brand products, and is also prepared by compounding pharmacies for individual patients. A compounded preparation is not FDA-approved and is not a generic or equivalent of any brand product.

Tirzepatide

A dual GIP and GLP-1 receptor agonist. As with semaglutide, it appears both in FDA-approved brand products and in compounded preparations, and those two things are not interchangeable.

Orforglipron

An orally available small molecule that activates the GLP-1 receptor. Because it is not a peptide, it does not need the absorption enhancer that peptide tablets require.

Titration

Dose escalation

Starting at a low dose and stepping up on a schedule your clinician sets, so the body has time to adjust. Titration is about tolerability, not speed.

Maintenance dose

The dose a clinician settles on once titration is finished and the plan is steady, rather than still climbing.

Gastric emptying

How quickly the stomach passes food into the small intestine. GLP-1 medicines slow it, which is a large part of why fullness lasts longer - and also why nausea is the most common early complaint.

Food noise

Intrusive food thoughts

The informal term patients use for the constant background pull toward eating. It is not a clinical diagnosis; it is simply the description most people reach for.

Subcutaneous

Sub-Q, SC

Into the fatty layer just under the skin rather than into muscle or a vein. Most weight-management injections are subcutaneous.

Plateau

A stretch where weight stops moving despite an unchanged routine. Common, expected, and a normal reason to check in with your clinician rather than to give up.

Lean mass

Fat-free mass

Everything that is not fat - muscle, bone, organs, water. Any weight-loss approach can cost lean mass, which is why protein intake and resistance training come up in these visits.

Pharmacy & compounding

The distinctions that decide what a medication legally is, who made it, and what has or has not been reviewed.

Compounded medication

Compounded preparation

A medication prepared by a licensed pharmacy for an individual patient under a prescription written for that patient. Compounded medications are not FDA-approved. FDA does not review them for safety, effectiveness, or quality before marketing.

FDA-approved

A specific legal status meaning FDA reviewed that exact product from that manufacturer and approved its labelling. It applies to a named brand product, not to an ingredient in general, and it never transfers to a compounded preparation.

Generic

A copy of an FDA-approved drug that FDA has itself reviewed and found therapeutically equivalent. A compounded preparation is not a generic, no matter how similar the ingredient sounds.

Section 503A pharmacy

Traditional compounding pharmacy

A pharmacy compounding for individually identified patients under a prescription, registered with its state board. The section number describes the legal category it operates under. It is not an FDA approval, certification, endorsement, or quality seal.

Section 503B outsourcing facility

A facility that may compound in larger batches and registers with FDA. Registration is not the same as approval of anything it makes.

Active pharmaceutical ingredient

API

The component of a preparation responsible for its intended effect, as distinct from the buffers, preservatives and diluents around it.

Bacteriostatic water

BW

Sterile water containing a preservative that inhibits bacterial growth, used by pharmacies to reconstitute certain medications. How a specific medication is prepared is determined by the pharmacy and the prescription - never by a patient improvising.

Cold chain

Keeping a temperature-sensitive medication within its required range from pharmacy to doorstep. It is why shipments arrive with insulated packaging and a cold pack.

Healthy aging

Terms from the longevity side of the catalogue - what a peptide actually is, and what these molecules act on.

Peptide

A short chain of amino acids - the same building blocks as proteins, just fewer of them. Insulin is a peptide. Peptides are not anabolic steroids and are not human growth hormone; they are a broad chemical category, not a drug class.

Secretagogue

A substance that prompts the body to release something it already makes. Sermorelin is described this way because it acts on the pituitary rather than supplying a hormone directly.

Sermorelin

A peptide corresponding to a fragment of growth-hormone-releasing hormone. It acts on the pituitary gland, which is the basis for describing it as working through the body’s own signalling rather than replacing a hormone.

NAD+

Nicotinamide adenine dinucleotide

A coenzyme present in every cell, involved in the reactions that convert nutrients into usable energy and in several repair pathways. Levels of it are a subject of active research.

Mitochondria

The structures inside cells where most usable energy is produced. Several longevity conversations circle back to them.

Glutathione

A molecule the body makes from three amino acids, involved in antioxidant and detoxification pathways in the liver and elsewhere.

GHK-Cu

Copper tripeptide-1

A copper-binding tripeptide found naturally in plasma, studied for its role in skin and connective-tissue processes.

MIC

Methionine, inositol, choline

A combination of nutrients that appear in liver and fat-metabolism pathways, often given alongside vitamin B12.

Sexual health

How the erectile-function medications are classified and what distinguishes them from one another.

PDE5 inhibitor

Phosphodiesterase type 5 inhibitor

A class of medication that blocks an enzyme which would otherwise break down a signalling molecule involved in blood-vessel relaxation. Sildenafil and tadalafil both belong to this class.

Sildenafil

A PDE5 inhibitor, the active ingredient in a well-known brand product. It is generally taken ahead of activity rather than on a fixed daily schedule.

Tadalafil

A PDE5 inhibitor with a notably longer duration of action than sildenafil, which is why clinicians sometimes discuss a low daily dose as an alternative to as-needed use.

Nitric oxide

NO

A signalling molecule that relaxes the smooth muscle lining blood vessels. PDE5 inhibitors work downstream of it, which is why they need that natural signal present to do anything at all.

As-needed vs daily

PRN vs daily dosing

Two different plans a clinician may discuss: taking a dose ahead of activity, or a smaller dose on a routine schedule. Which is appropriate is a clinical decision, not a preference to self-select.

Hair loss

The two mechanisms that hair-loss medications work through, and the vocabulary around them.

Androgenetic alopecia

Male or female pattern hair loss

The most common pattern of hair loss, driven by an inherited sensitivity of hair follicles to certain hormones.

DHT

Dihydrotestosterone

A hormone converted from testosterone. In genetically susceptible follicles it is associated with the shortening of the growth phase that produces pattern hair loss.

5-alpha reductase inhibitor

A medication that reduces the conversion of testosterone into DHT. Finasteride belongs to this category.

Minoxidil

A medication originally developed for blood pressure, later found to affect hair growth. It is used topically and, in some cases, orally - a decision only a clinician should make.

Anagen

Growth phase

The active growing phase of a hair follicle. Most hair-loss conversations are ultimately about how long this phase lasts.

Shedding phase

Dread shed

A temporary increase in hair falling out after starting certain treatments, as follicles synchronise into a new cycle. Expected in some cases - worth raising with your clinician either way.

Care & coverage

How a telehealth visit is structured and the terms that appear when insurance enters the conversation.

Telehealth

Telemedicine

Care delivered remotely by a licensed clinician. What a clinician may prescribe, and to whom, is governed by the licensing rules of the patient’s own state.

Asynchronous visit

Store-and-forward

A visit where you submit your history and a clinician reviews it and responds, rather than meeting live. Whether this is permitted depends on the state and the medication.

Intake

Health questionnaire

The medical history you complete before a clinician reviews your case. Completing an intake is not a prescription and does not guarantee one.

Contraindication

A specific reason a medication should not be used in a specific person. Contraindications are why not everyone qualifies, and why an honest intake matters more than a fast one.

Off-label

Prescribing an FDA-approved medication for a use other than the one on its approved labelling. It is lawful, common, and a clinical judgement made case by case.

Prior authorization

PA

A requirement from an insurer that a prescriber justify a medication before the plan will cover it.

Formulary

The list of medications a given insurance plan covers, and at what tier. A medication being widely used does not mean a particular plan lists it.

Still have a question about a word?

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