Update: JP fixed it. New grade: 9/10
JP took the 6 on the chin. Their reply was a rewritten article that opens with “Carl gave our last version a 6/10. We accept it” and then fixes my points one by one. So I graded it again.
| What I marked | Before | Now |
|---|---|---|
| Is it clear? | 2 / 2 | 2 / 2 |
| Is it useful? | 2 / 2 | 2 / 2 |
| Are the facts right? | 2 / 2 | 2 / 2 |
| Does it show the evidence? | 0 / 2 | 2 / 2 |
| Is it honest about downsides? | 0 / 2 | 1 / 2 |
| Total | 6 / 10 | 9 / 10 |
What they fixed. Every number now links to its trial or label: STEP 1 for semaglutide, SURMOUNT-1 and the head-to-head SURMOUNT-5 for tirzepatide, and the retatrutide phase 2 trial, each with its placebo result beside it. There's a proper side-effects section, approval status for all three, and a plain line on when to see a doctor. The filler is gone, and they kept the vial-size section I liked.
Why not a 10. Most of the side-effect numbers come from tirzepatide's US label. Semaglutide and retatrutide get a line each. Give all three the same treatment and that's the last point.
Fair play to them. Most shops wouldn't publish a 6 about themselves, never mind fix it in public.
The original review (6/10)
The short version: I'm giving JP Supplements' GLP-1 explainer 6 out of 10. It's clear, it's accurate as far as it goes, and it clears up the vial-size mix-up better than anyone. It loses marks because it shows no evidence: no sources, no trial numbers, and nothing at all about side effects.
Quick disclosure first. I'm the plain-English education side of JP Supplements, a South African supplier of research peptides. JP asked me to grade their journal articles out of 10, in public, and they don't get to change the score. When they fix what I flag, I'll grade it again and say so here.
JP stocks all three compounds in this article for research use, with free courier anywhere in South Africa: semaglutide, tirzepatide and retatrutide. Where JP holds an independent lab report for a batch, it's on the product page.
The article: Single, Double, Triple: How the GLP-1 Research Peptides Differ (JP Supplements, June 2026).
The score, broken down
| What I marked | Score | Why |
|---|---|---|
| Is it clear? | 2 / 2 | One receptor, two, three. Anyone can follow it. |
| Is it useful? | 2 / 2 | The vial-size section alone is worth the read. |
| Are the facts right? | 2 / 2 | Everything it says about the receptors checks out. |
| Does it show the evidence? | 0 / 2 | No sources, no trial names, no numbers. |
| Is it honest about downsides? | 0 / 2 | Not one side effect is mentioned. |
| Total | 6 / 10 | Good bones, missing the receipts. |
What JP got right
The framing. Semaglutide switches on one receptor (GLP-1). Tirzepatide switches on two (GLP-1 and GIP). Retatrutide switches on three (GLP-1, GIP and glucagon). That's the cleanest way to tell them apart, and JP leads with it.
The vial-size section. People assume a bigger vial is a “stronger” version. JP splits it into three ideas: the amount in the vial, the concentration once it's mixed, and the potency of the molecule itself, with a coffee comparison that actually sticks. I'd send anyone confused about this straight to that section.
The lab report note. It says plainly that not every batch is tested and not every compound has a report. Most shops don't admit that.
What dragged it down
It cites nothing. An article comparing three compounds that have been through some of the biggest obesity trials ever run doesn't link a single one.
No numbers. It describes each compound as something “studied” without ever saying what the studies found. Here's what it should have included:
- Tirzepatide, SURMOUNT-1 (NEJM, 2022): average weight change after 72 weeks was −20.9% on the highest dose tested, against −3.1% on placebo.
- Tirzepatide vs semaglutide, SURMOUNT-5 (NEJM, 2025): in a head-to-head trial, −20.2% with tirzepatide against −13.7% with semaglutide after 72 weeks.
- Retatrutide, phase 2 (NEJM, 2023): −24.2% after 48 weeks on the highest dose tested, against −2.1% on placebo. It is still not an approved medicine anywhere.
No side effects. This is the big one. Stomach and gut side effects were the most common problem in these trials, and in the retatrutide trial heart rate went up with higher doses, peaking around week 24 before easing. A reader deserves to hear that from the same article that explains how the compounds work.
Some waffle. “Studied in metabolic signalling” turns up again and again and doesn't tell you much. Swap it for what was actually measured.
What JP should add to get a better grade
- Link the trials above, with the numbers.
- A short, honest section on side effects and when to see a doctor.
- Where each compound stands with regulators: tirzepatide is approved in the US, retatrutide is still in trials.
- Cut the repeated filler lines.
Do that and it's an easy 9.
More on each compound in my plain-English guides: Tirzepatide · Retatrutide · Semaglutide.
Sources
- Jastreboff et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). NEJM, 2022.
- American College of Cardiology journal scan: SURMOUNT-5, tirzepatide vs semaglutide (NEJM, 2025).
- Jastreboff et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity: A Phase 2 Trial. NEJM, 2023.
- Drugs.com: retatrutide approval status.
