Glossary

503A pharmacy

A traditional compounding pharmacy that makes drugs for individual patient prescriptions.

503A vs 503B

503A: traditional pharmacy compounding per prescription. 503B: outsourcing facility, FDA-registered, bulk.

503B bulks list

FDA list of drugs outsourcing facilities may compound from bulk substance. Semaglutide proposed for removal April 2026.

503B outsourcing facility

Federally-registered compounding facility that can produce drugs in bulk for healthcare settings.

Anti-obesity medication (AOM)

Drugs FDA-approved specifically for chronic weight management, like Wegovy and Zepbound.

Asynchronous care

Care delivered without a live appointment, you submit forms/photos, a clinician reviews on their own time.

Azelaic acid

Topical for acne and rosacea. Reduces inflammation and pigmentation. Safe in pregnancy.

BMI

Body Mass Index. Weight in kg divided by height in meters squared. Screening tool.

Boxed warning

The FDA's strongest warning. GLP-1s carry one for thyroid C-cell tumor risk.

Clomid (clomiphene)

Older ovulation induction drug. Second-line after letrozole.

Compounded GLP-1

A custom version of semaglutide or tirzepatide made by a 503A/503B pharmacy, not FDA-approved.

Continuous glucose monitor (CGM)

A wearable that tracks blood glucose. Sometimes paired with GLP-1 programs for T2D.

DEA telehealth rule (2025)

Federal rule narrowing telehealth controlled-substance prescribing after the COVID-era flexibilities expired.

DHT

Dihydrotestosterone. The androgen that miniaturizes hair follicles in male-pattern baldness.

Dutasteride

Off-label hair-loss drug. Blocks DHT more completely than finasteride.

EPC

Earnings per click. How affiliate programs measure the value of traffic they receive.

Estrogen

Female sex hormone. Main HRT component for menopause symptoms.

FDA shortage list

FDA's official list of drugs currently in shortage. Drives compounding eligibility.

Finasteride

Oral pill that blocks DHT, the hormone driving male-pattern hair loss.

Formulary

The list of drugs an insurance plan covers, organized into cost tiers.

GIP

Glucose-dependent insulinotropic peptide. The second hormone tirzepatide hits.

GLP-1

A gut hormone that triggers insulin release and slows stomach emptying. Drug names imitate this hormone.

GLP-1 microdosing

Using sub-therapeutic GLP-1 doses, often marketed by compounders. Limited evidence.

Gastric emptying

How fast food leaves the stomach. GLP-1s slow it, driving fullness and nausea.

HRT (Hormone Replacement Therapy)

Estrogen ± progesterone to treat menopause symptoms. Transdermal preferred over oral.

Incretin

Class of gut hormones that boost insulin after meals. GLP-1 and GIP are the two main incretins.

Isotretinoin (Accutane)

Oral retinoid for severe acne. Highly effective, requires monthly monitoring + iPLEDGE.

Lean mass

Non-fat body weight (mostly muscle). 20-40% of GLP-1 weight loss can be lean mass.

Letrozole

Aromatase inhibitor. First-line ovulation induction for PCOS-related infertility.

LillyDirect

Eli Lilly's direct-to-consumer cash-pay channel for Zepbound, Mounjaro, and orforglipron.

Liraglutide

Daily-injection GLP-1 (Saxenda, Victoza). Older than semaglutide, weaker, less popular.

MASH (formerly NASH)

Inflammatory fatty liver disease tied to obesity. GLP-1s show histologic benefit.

Maintenance dose

The steady target dose after titration (e.g. Wegovy 2.4mg, Zepbound up to 15mg weekly).

Manufacturer savings card

A copay card from the drug maker that lowers cost for commercially-insured patients.

Medullary thyroid carcinoma (MTC)

A thyroid cancer type. Personal/family history contraindicates GLP-1 use.

Metformin

Oral diabetes drug. Used in PCOS for insulin resistance and (off-label) weight.

Minoxidil

Topical (or oral) drug that increases blood flow to hair follicles.

Mounjaro

Branded tirzepatide for type 2 diabetes.

Multiple Endocrine Neoplasia type 2 (MEN 2)

An inherited syndrome raising MTC risk. Contraindicates GLP-1 use.

NDT (Natural Desiccated Thyroid)

Thyroid hormone replacement derived from porcine thyroid. Contains both T4 and T3.

Niacinamide

Vitamin B3 topical. Reduces redness, oil, pigmentation. Pairs with almost everything.

NovoCare

Novo Nordisk's direct-pay self-pay program for Wegovy and other branded GLP-1s.

Obstructive sleep apnea (OSA)

Airway collapse during sleep, linked to obesity. Zepbound gained an OSA indication in 2024.

Off-label use

Prescribing an FDA-approved drug for a use not on its label. Legal and common.

Orforglipron

First once-daily oral non-peptide GLP-1. Brand-only, launched via LillyDirect at $149/mo in 2026.

Ozempic

Branded semaglutide for type 2 diabetes (also widely used off-label for weight).

PCOS

Polycystic ovary syndrome. Combination of insulin resistance, androgen excess, irregular cycles.

PDE5 inhibitor

Drug class for ED. Sildenafil, tadalafil, vardenafil, avanafil. Blocks an enzyme to maintain erection.

Pharmacy benefit manager (PBM)

Middlemen who manage drug benefits for insurers and negotiate pharmacy pricing.

Prior authorization (PA)

Insurer requirement that a prescriber justify a drug before coverage applies.

Progesterone

Added to estrogen-based HRT for women with intact uterus to prevent endometrial cancer.

REMS

An FDA risk-management program some drugs require. GLP-1s do not have one.

Retinol

Over-the-counter vitamin A derivative. ~10-100x weaker than prescription tretinoin.

Rybelsus

Oral semaglutide pill for diabetes. The only oral GLP-1 currently FDA-approved.

SELECT trial

Landmark trial showing semaglutide cut cardiovascular events in obesity without diabetes.

SNRI

Antidepressant class that boosts both serotonin and norepinephrine. Often used when SSRIs don't work.

SSRI

A class of antidepressants that boost serotonin signaling. First-line for depression and anxiety.

SSRI vs SNRI

SSRIs boost serotonin only. SNRIs boost both serotonin and norepinephrine.

STEP trials

Semaglutide weight-management trial program. STEP 1 showed ~15% mean weight loss.

SURMOUNT trials

Tirzepatide obesity trial program. SURMOUNT-1 showed ~21% mean weight loss.

Sarcopenia

Age-related loss of muscle mass and strength. A reason to protect lean mass on GLP-1s.

Scheduled substance

DEA-classified controlled drug. Schedule I (illegal) to V (least restricted).

Semaglutide

Active ingredient in Ozempic, Wegovy, and Rybelsus. A GLP-1 receptor agonist.

Sermorelin

Synthetic peptide that stimulates the body's own growth hormone production.

Sildenafil (Viagra)

PDE5 inhibitor. 30-60 min onset, 4-6 hour duration. Generic available, cheap.

Spironolactone

Oral anti-androgen for adult hormonal acne in women. 50-100mg daily.

Step therapy

Insurer rule requiring you to try a cheaper drug first before a costlier one is covered.

Subcutaneous injection

An injection into the fat layer under the skin. How most GLP-1 pens deliver the drug.

Synchronous care

Live appointment with a clinician, video or phone, at a scheduled time.

TRT

Testosterone replacement therapy. For men with clinically low testosterone confirmed on bloodwork.

TSH

Thyroid-stimulating hormone. The blood test that diagnoses thyroid problems.

Tadalafil (Cialis)

Long-acting PDE5 inhibitor. 24-36 hour duration. Daily low-dose option for spontaneity.

Telehealth

Medical care delivered over video, phone, or messaging, without an in-person visit.

Thyroid

Butterfly-shaped gland in the neck that produces hormones regulating metabolism.

Tirzepatide

Active ingredient in Mounjaro and Zepbound. Hits two hormone receptors (GLP-1 + GIP).

Titration

The schedule of gradually increasing a medication dose to reach a target.

Topical finasteride

Compounded liquid finasteride applied to the scalp. Less systemic absorption than oral.

Tretinoin

Prescription-strength vitamin A derivative. Gold standard for anti-aging and acne.

Wegovy

Branded high-dose semaglutide for weight loss (Novo Nordisk).

Weight regain

Weight returning after stopping a GLP-1. Trials show ~two-thirds regained within a year.

Weight-related comorbidity

A weight-linked condition (T2D, hypertension, sleep apnea) that lowers the BMI threshold to 27.

Zepbound

Branded tirzepatide for weight loss (Eli Lilly).