Microdosing

Microdosing in this context means deliberately taking a GLP-1 at a dose below the approved ladder — often a fraction of the starting dose, sometimes indefinitely. It circulates in patient communities and in telehealth marketing as a way to get appetite control with fewer side effects, or to stretch an expensive vial.

Start with what is actually established. No GLP-1 label describes a microdosing regimen. The approved ladders exist because they were the doses tested: Wegovy from 0.25 mg to 2.4 mg weekly, Zepbound from 2.5 mg to 15 mg, Foundayo from 0.8 mg to 17.2 mg daily. Trial results such as the 14.9% average in STEP 1 and 20.9% in SURMOUNT-1 belong to maintenance doses reached after months of escalation. A dose below the labeled starting dose has not been studied for weight loss outcomes, so nobody can tell you what to expect from it.

That does not make every low-dose strategy irrational. The Zepbound label directs prescribers to consider treatment response and tolerability when selecting a maintenance dose, and 5 mg is an approved maintenance dose even though 15 mg produced more loss. Staying lower because you are doing well and tolerating it poorly at the next step is a legitimate clinical choice. The distinction is between a labeled dose chosen deliberately and an unlabeled fraction chosen to save money.

The practical hazard sits with compounded vials, where microdosing usually happens, because the dose is drawn in units rather than dispensed in a fixed pen. FDA recommends discarding a multi-dose vial within 28 days of first use even if medication remains — which directly conflicts with stretching a vial across months — and advises a new sterile needle and syringe for every dose.

Ask your prescriber whether a low dose is a plan or a workaround, what result would justify moving up, and how vial dating is being handled. Our reverse dose calculator and microdosing evidence guide set out what is and is not known.