Instructor Notes — Chapter 15

Growth Hormone Secretagogues: CJC-1295, Ipamorelin, Tesamorelin, MK-677 Part 3 · intermediate · prerequisites: Chapters 3, 14, 5

What this chapter is actually for

Chapter 15 carries more instructional weight than its position suggests. It is the book's designated place for teaching the surrogate-to-outcome inference, and §15.7 is written to be lifted and reused on compounds that do not yet exist. If a student finishes the chapter able to recite the four ratings but cannot say what step of the diagram a given claim sits on, the chapter has failed.

Plan your time accordingly. §§15.1–15.5 are content delivery and can move briskly. §15.6 and §15.7 should absorb at least half of your contact hours.

The room you are actually teaching

Assume that some fraction of any given cohort uses or has used these compounds, and that they will not announce it. This changes the pedagogy in a specific way: the chapter's arguments must be delivered in an order that does not make anyone defensive before they have heard them.

The chapter models this and you should follow it. Lead with the concession — these compounds do raise growth hormone, the mechanism is real, tesamorelin proves it can reach a clinical outcome. Only then introduce the gap. An instructor who opens with "none of this works" will lose exactly the students the chapter is written for, and will also be saying something the chapter does not say.

Two sentences worth having ready verbatim:

• "The disagreement is not about whether the compound does something. It is about whether what it does is the thing it was sold as doing."
• "A reader who has watched their IGF-1 panel move is not imagining it."

Sequencing and emphasis

§15.1 — The one thing to drill is that a single random GH measurement is nearly uninterpretable. Students consistently under-appreciate this and it recurs in every later evaluation task. Consider opening with the exercise 15.2 scenario before any lecture.

§15.2 — The DAC mechanism is a good place to reward students who remember albumin binding from Chapter 4. The high-value item is the two-molecules-one-name problem; students find it genuinely surprising and it generalizes to the whole gray market.

§15.3 — The "selective therefore safe" Hype Check is the chapter's clearest example of a valid premise supporting an invalid conclusion. Worth diagramming on a board: selectivity is a claim about receptors; safety is a claim about people over time.

§15.4 — Emphasize MK-677 is not a peptide early and repeatedly; it appears on quizzes and students who have absorbed the chapter's framing sometimes over-generalize the peptide arguments to it. Figure 15.1 is the single most important study in the chapter.

§15.5 — The double lesson is easy to half-teach. Students will take away either "tesamorelin proves the class works" or "tesamorelin is irrelevant to the class." Both are wrong and the chapter says so. Make them state both halves in one sentence before moving on.

§15.6 — Do not shortcut the steelman. Have students produce the four-point pro-secretagogue argument before you present any counter-argument (exercise 15.14 is designed for this). If you present the counter-arguments first, students will produce a weak steelman and the section will teach nothing.

§15.7 — The seven-step diagram should end up on a board, reproduced from memory, more than once. Every subsequent claim-evaluation exercise in the course can be run against it.

§§15.8–15.9 — Fast. These are consolidation, not new content. The one item worth dwelling on is why MK-677 outranks CJC-1295 + ipamorelin despite being the less reputable compound.

Common student errors, in order of frequency

1. Treating a rating as a property of a molecule. "Is tesamorelin good?" is not a question the system answers. Redirect to claim, population, endpoint every single time.
2. The GnRH over-extension. After Case Study 15.2, a predictable fraction of students will assert that CJC-1295 with DAC suppresses the GH axis. It has not been shown to. This is the same error the book criticizes running in the opposite direction, and catching students committing it is one of the most valuable teaching moments available. Exercise 15.18 and case study question 1 are both built to surface it.
3. Confusing "no evidence of effect" with "evidence of no effect." Especially for the ❌ ratings.
4. Forgetting that lean mass may be water. This is the technical detail that most often decides an argument in the students' favor when they debate outside class.
5. Reading ⚠️→❌ as a trajectory. It is a distinction between two claims, not a prediction. Say so.

Assessment guidance

exercises.md has 36 items across sections A–G with 10 marked †. The † items are argumentative or open and should be graded on reasoning quality, not conclusion. Exercises 15.31 (steelman mechanism) and 15.33 (what you would actually say) are the two best single indicators that a student has absorbed the chapter's posture rather than its conclusions.

quiz.md has 22 items with an answer key. Items 11, 14, 16, and 19 are the discriminating ones. Item 14 is the GnRH over-extension trap and should be discussed rather than merely marked.

Worked solutions and marking guides are in _scratch/answers/ch15.md.

Safety and framing constraints

This chapter is the highest-risk in the book for accidentally producing an instruction sheet. Instructors should not supplement it with dosing, protocol, sourcing, or administration content, in class or in response to questions. If asked directly, the correct answer is that this course teaches evaluation of evidence and that dosing decisions belong with a clinician who can see the student's history and order labs.

The chapter's own compliance posture: no mg figures anywhere, no brand names, two descriptive references to an approved label in past tense, no vendors, no named individuals.