Search “sermorelin timeline” and you will find week-by-week promises: more energy by week two, better sleep by week four, a visible body-composition change by week eight or twelve. Almost none of that is sourced to an actual trial visit. There is exactly one adult sermorelin study with a defined visit schedule, and its real calendar looks different from the marketing one. This page follows that calendar, visit by visit, and separates what a chart from that study would show from what a seller’s landing page claims. For the outcomes themselves rather than the schedule, see what the trial actually found.
The one trial with a real schedule
Nineteen adults aged 55 to 71 (n = 19: ten women, nine men) completed a single-blind, placebo-controlled trial that ran five months. The design: four weeks of nightly placebo first, then sixteen weeks of nightly [Nle27]GHRH-(1-29)-NH2 at 10 micrograms per kilogram, self-injected subcutaneously. Once the active drug started, participants were checked at 2, 4, 8, and 12 weeks. Blood pressure, body weight, and fasting insulin and glucose were recorded at every one of those four visits [1]. Full body composition, skin thickness, and quality-of-life questionnaires ran on a different schedule — compared only at the study’s start and at the 16-week endpoint.
That distinction matters. A blood draw and a weight check are one kind of visit. A body-composition scan or a sleep questionnaire is another. The trial ran both. It just ran them on different clocks.
Week by week, what was actually tracked
Night one. The first injection produced a growth hormone pulse within 10 minutes, lasting about two hours. That effect appeared on the very first dose and held across the study [1]. This is a mechanism finding, not a felt or measured benefit.
Week 2. Serum IGF-I rose significantly (P < 0.05), and IGFBP-3 rose more sharply (P < 0.001) [1]. This is the earliest point in the whole literature where anything measurable changed on paper.
Week 4. A companion paper on the same cohort reported a large rise in growth hormone secretion by this point: up 107% in men, 70% in women, with IGF-I up 28% in both sexes over the same window [2]. Growth-hormone binding protein also rose significantly in women, though not in men, by week 4 [1]. Immune-cell activation markers moved in the same window, per the companion paper [2].
Weeks 8 and 12. The published report ties no new finding specifically to these two visits. The biomarker picture kept moving quietly: IGFBP-1 stayed elevated through week 12, then drifted back toward baseline by week 16 [1]. Blood pressure, weight, and fasting glucose and insulin were recorded at both visits and described as unchanged overall.
Week 16, the trial’s endpoint. This is where the outcomes people actually search for were measured against baseline, all at once. Skin thickness increased in both sexes. Lean body mass increased in men only. General well-being and libido improved in men only. Sleep quality did not change in either sex. Insulin sensitivity, measured by a glucose tolerance test, improved in men only [1]. See the full sex-split before-and-after read for what that endpoint did and did not show.
A placebo month hides inside the trial
There is a design detail worth flagging on its own. Before any active drug, every participant self-injected nightly placebo for four full weeks. Only after that did the 16-week active phase and the 2, 4, 8, and 12-week checkpoints above begin. A seller’s “week 1” usually means the first week a product ships. The trial’s “week 1” meant the first week of actual drug, after a full month of blinded saline. Those are not the same clock, and no marketing timeline flags the difference. The nightly dosing pattern itself is covered separately in why sermorelin is dosed at night.
What no trial has tracked in the first 12 weeks
A PubMed search for sermorelin combined with “weekly” or “time course” returns eight records. None is a human time-course study of adult outcomes — they are receptor chemistry, forensic detection assays, and studies in unrelated species. A separate search, sermorelin restricted to randomized trials, returns ten records total. The trial above is the only one with an adult, non-pediatric outcome and a defined visit schedule. There is no second trial to check it against, at any week.
That means nobody has published week-4, week-8, or week-12 data on body composition, sleep, or energy in adults taking sermorelin. Those outcomes exist at exactly one timepoint in the literature: the 16-week endpoint, and only in men. It is worth naming what this is not: it is not proof that nothing happens in the first twelve weeks. It is a statement about what has and has not been published. A felt change in week three would not contradict the trial; it simply would not be backed by anything the trial measured that early. What a rising IGF-I number can and cannot tell you about that early window is covered in the IGF-1 testing breakdown.
The gap between the trial calendar and the marketing calendar
A seller’s week-by-week program guide often assigns a specific benefit to a specific early week: noticeable energy by week two or three, sleep improvement by week four, visible composition change by week eight. None of that maps onto what was actually checked at those visits in the one trial that exists. What got checked early was blood chemistry and vital signs. What moved on paper early was IGF-I, IGFBP-3, and growth-hormone secretion — biomarkers, not something a person would notice. The felt or measured changes, where they existed at all, showed up at the four-month mark, and only in half the study population.
The bottom line
The honest first-12-weeks story is short: a hormone pulse on night one, a biomarker rise by week two, more biomarker movement by week four, unremarkable vitals through weeks eight and twelve, and the only outcome data sitting at week sixteen, in men. Anything more specific than that, assigned to an earlier week, is not coming from a trial visit. Sellers that publish an actual dosing and visit schedule rather than a marketing timeline are listed on the injections board.