Glossary
82 plain-English definitions of telehealth terms we use across the site. Search by term or definition, or browse A-Z.
5
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.
A
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.
B
C
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.
D
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.
E
F
G
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.
I
L
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.
M
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.
N
O
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).
P
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.
R
S
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.
T
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.