---
date: "2020-01-26T20:41:55.827Z"
title: "Transfeminine HRT"
description: "An introduction to feminizing hormone replacement therapy."
classes:
  - hrt
siblings:
  next: /hrt/fem/antiandrogens
  nextCaption: Anti-Androgens
---

# Transfeminine HRT - Introduction

{!{ <div class="gutter d-md-block d-sm-none"><div class="card"><div class="card-body"><h4 class="card-title">For Your Information</h4> }!}

The term "**Transfeminine**" describes a transgender person whose body either naturally produces testosterone by way of testicles and was likely assigned Male at birth, or an intersex individual who experienced male puberty due to the introduction of testosterone treatment and is now transitioning to estrogen treatment due to a female gender identity.

The term is not synonymous with other transgender terms such as **AMAB** (Assigned Male at Birth) or **MTF** (Male to Female), as it bears no relevance to the cultural factors of ones birth, nor to the gender of the individual. It only describes the direction of the endocrine transition. The term is sometimes abbreviated as transfem or transfemme.

{!{ </div></div></div> }!}

Before I can get into the medication specifics, I need to introduce the concept of a Receptor, because this is central to how all medications work, and understanding this concept will make it easier to understand the differences in these drugs.

### Hormone Receptors

In simplest terms, a receptor is like the keyed lock ignition on a car built prior to 2010 (do new car’s still have keyed ignitions?). Every cell in the body has a set of protein receptors which activate different functions within that cell. They’re like switches which signal to the cell that it should behave a certain way. Each receptor can only accept certain chemical compounds, much like how an ignition can only accept certain keys, and different chemicals have different capabilities at turning the ignition. Some can completely start the car, while others only turn it to Accessory Mode.

The ability for a chemical to fit into a receptor is called *Relational Binding Affinity,* and is measured as how likely a chemical will bind to a receptor compared to another. So, for example, if Hormone B binds only 10% of the time in relation to Hormone A, then it is said to have a 10% affinity. Similarly, the ability for a compound to turn the key is called *Transactional Ability*. Compounds which into a receptor but don’t do anything are called *Antagonists*, compounds which are able to turn the key are called *Argonists*. If it can only turn the key a tiny bit, it’s called a *Partial Argonist*.

You can think of antagonists like bouncers at a club. They stand in the doorway and prevent anything else from getting through, but don’t enter the club themselves. Most antagonists are referred to as Blockers. This is different from an *Inhibitor*, which is a compound that slows a chemical reaction. In receptors, an inhibitor lowers the function of the receptor, causing it to respond less effectively to things that bind to the receptor.

Right, now that we've covered that, lets move on.

**This guide is divided into four parts:**

1. [Anti-Androgens](/hrt/fem/antiandrogens)

2. [Estrogens](/hrt/fem/estrogens)

3. [Progestins](/hrt/fem/progestins)

4. [What to Expect When You're Expecting Boobs](/hrt/fem/what-to-expect)

For further reading beyond this guide, I recommend the [University of California, San Francisco's Feminizing Hormone Therapy Guidelines.](https://transcare.ucsf.edu/guidelines/feminizing-hormone-therapy).
