TRT Terms Decoded: Your Bloodwork and Protocol Words in Plain English

Educational, not medical advice. Definitions here are meant to help you read your own labs and forums with less confusion, not to guide a protocol.

Your bloodwork

• Total testosterone: All the testosterone in your blood, bound and free. The default number labs give you. It's the front door, but it can mislead you. See free vs total testosterone.
• Free testosterone: The small slice not locked up by SHBG. It's the part your body can actually use, so it tracks how you feel.
• SHBG (sex hormone binding globulin): A protein that grabs testosterone and holds it hostage. High SHBG locks up more of your total; low SHBG frees more of it up. It's why two guys with the same total T can feel completely different.
• Albumin: Another blood protein testosterone rides on, but loosely. You need it to calculate free T properly.
• Hematocrit: The percentage of your blood that's red blood cells. TRT pushes it up. Above about 54% is where doctors step in, because thick blood raises clot risk. See the hematocrit management guide.
• Hemoglobin: The oxygen-carrying part of red blood cells. Rises alongside hematocrit on TRT.

Estrogen stuff

• Estradiol (E2): The main estrogen. Men need it for bones, libido, and mood. Some of your testosterone converts into it, and that's normal.
• Aromatization: The conversion of testosterone into estrogen. Not a malfunction. It's supposed to happen.
• Aromatase inhibitor (AI): A drug like anastrozole that blocks that conversion. Rarely actually needed, and easy to overdo. See do you actually need an AI on TRT.

Dosing stuff

• Ester: The chemical tail on your testosterone (cypionate, enanthate) that controls how slowly it releases. Cypionate and enanthate are near-identical and dosed the same way. See cypionate vs enanthate.
• Trough: Your lowest level, right before your next shot. Where you feel the dip.
• Peak: Your highest level, shortly after injecting.
• Half-life: How long it takes for half a dose to clear. It drives how often you inject.
• SubQ vs IM: Injecting into fat (subcutaneous) vs muscle (intramuscular). Both work.
• Microdosing: Splitting your weekly dose into smaller, more frequent shots. Popular for smoother levels. The proven part is "don't take big infrequent doses," the rest is preference. See the injection schedule guide and microdosing TRT guide.

Track every dose, lab, and symptom in Regimen

• Smart reminders so you never miss a dose
• Progress tracking with photos and weight
• Medication level curves for every compound

Get Regimen Free

Fertility stuff

• LH / FSH: The brain signals that tell your testes to make testosterone and sperm. TRT shuts these down.
• hCG: Mimics LH to keep your testes working while you're on TRT. See the hCG on TRT protocol guide.
• SERM (clomid, tamoxifen): Nudges your brain's signal back up. Used to restart after TRT.
• Enclomiphene: A SERM used to raise your own testosterone as an alternative to TRT. See enclomiphene vs TRT.

Forum slang

• "Dialed in": When your dose, your labs, and how you feel all line up and you're stable. The goal. See what "dialed in" actually means.
• "Crashed E2": Estrogen dropped too low, usually from too much AI. Feels like dead libido, achy joints, and a flat mood.

Frequently asked questions

What's the difference between free and total testosterone?

Total is all of it; free is the usable slice not locked up by SHBG.

What does "dialed in" mean on TRT?

Your dose, labs, and how you feel are all lined up and steady.

What is crashed E2?

Your estrogen dropped too low, usually from overusing an AI. It feels worse than high E2 for most guys.