Retatrutide

You'll lose muscle too. But know what the study says before you decide.

Let's put this first, because it's what you care about and nobody writes it: incretin drugs cost lean mass. About 10%, or 6 kg — “comparable to a decade or more of aging”, as the review in Diabetes Care puts it 2. This applies to the whole category, not just here.

And now the finding that changes the picture. In the DXA substudy, retatrutide cut fat by 26.1% at 36 weeks — versus 4.5% on placebo and 2.6% on dulaglutide. And the ratio of lean mass to total loss came out the same as with the other treatments 1.

Read that again: you lose more, you don't lose worse. The extra that comes off comes off the fat.

And the countermeasure isn't theory — it's written in the same review. Resistance training over 10 weeks: about 3 kg of lean mass and +25% strength 2. The authors explicitly recommend it alongside treatment, and note that preserving lean mass may slow weight regain once treatment stops.

The cut number, for completeness: −24.2% total body weight in 48 weeks, and 83% of those on the high dose lost more than 15% 3.

So the pharmacological part is solved. The muscle part is your job — and you already know how it's done.

Three more, and one of them hasn't been answered. Blood sugar: HbA1c −2.02% at 12 mg, vs −0.01% on placebo and −1.41% on dulaglutide 6. Heart: an outcomes trial doesn't exist yet — it reports in 2029. Kidneys, preliminary: albuminuria −37% and eGFR +8.5, but most participants had normal kidneys at baseline, so the absolute change was small — the authors say so themselves 4. The trial in genuinely diseased kidneys finished in October 2025 and hasn't been published 5.

Four formats. Choose by what suits you, not by what sounds better.

Syringes: four single-dose, pre-filled at your dose — no measuring, no drawing up, no chance of getting lost in the zeros. One month. Pen: the same four doses in one device, with the extra charge.

Watch the pen number. “1 × 8 mg” isn't 8 mg in one go — it's 4 × 2 mg, a month in one pen. Always four times the dose, because it carries all four weeks.

Vial: plain powder, the cheapest per mg. You do the work — reconstitution, calculation, your own syringes. Reconstituted vial: the same, dissolved in 2 mL bacteriostatic water with 4 syringes included, +10 €.

The trade-off: the solution has a clock, the powder doesn't. Once reconstituted it needs the fridge and won't wait months. If you're starting now, it's convenient; if you're stocking up, get the powder.

Four formats, and the difference is how much of the work you do. Syringes: none. Pen: none, and everything in one device. Reconstituted vial: arrives ready, with syringes. Lyophilized powder: you prepare it, and it's the most stable over time. Choose by what you'll actually do — not by what sounds more serious.

−24.2% in 48 weeks. Almost one kilo in every four — a figure from the phase 2 trial in the New England Journal of Medicine, with 338 people 1. It's not an advertising slogan, it's a published finding.

The secret is that it flips three switches, not one. GLP-1 and GIP cut your appetite. Glucagon turns up the burn from within, like a second little furnace switching on.

And the most impressive part isn't even the weight. In the fatty liver substudy, liver fat dropped 82.4% in 24 weeks — 86% ended up below the normal threshold, versus 0% on placebo 2.

It's still a new molecule; phase 3 is running now, the TRIUMPH trials. You're seeing it at the point research centers themselves are seeing it, before it has the chance to get expensive.

A practical secret: start from the lowest dose — the same trial showed much milder gastrointestinal side effects that way 1. A research product, with quality control on every vial — not human dosing.