Semaglutide Microdosing: The Ladder, the Data and the Gaps

Semaglutide is the drug the word “microdose” gets attached to most often, and it is also the drug where the evidence gap is widest. STEP 1 randomised one dose against placebo. That dose was 2.4 mg weekly. Everything below it in the label is a tolerability step, so the honest answer to “what does 0.1 mg do” is that no trial has looked. This page lays out the ladder, the trial figures, and the risks that do not move when the dose does.

The approved semaglutide titration ladder

Injectable semaglutide steps 0.25, 0.5, 1.0, 1.7 and 2.4 mg weekly, four weeks per step, with 2.4 mg as the weight-management maintenance dose. Sixteen weeks of ramp before anyone reaches it.

There is also an oral product now. FDA approved once-daily oral semaglutide 25 mg on 22 December 2025 for weight reduction, long-term weight maintenance and reduction of cardiovascular event risk. Rybelsus, the diabetes tablet, uses a different range at 3, 7 and 14 mg.

What “microdose” means for semaglutide in practice

Clinic and industry sources describe a semaglutide microdose as roughly 0.05 to 0.25 mg weekly, which is at or below the label's first step. That range is a description of what people do. It is not evidence of anything, the sources reporting it are commercial, and no regulator or pivotal trial recognises the category.

Read against the ladder above, a 0.1 mg weekly dose is around one twenty-fourth of the dose that produced the STEP 1 result. That is the scale of the extrapolation being made when someone quotes trial weight loss on a microdosing page.

STEP 1, and what it does not tell you

STEP 1 found 14.85% mean body-weight loss at week 68 on semaglutide 2.4 mg weekly, against 2.41% on placebo. Among treated participants, 86.4% lost at least 5% of body weight, versus 31.5% on placebo.

The trial escalated everyone from 0.25 mg to 2.4 mg over 16 weeks. There was no low-dose arm. That single design fact is why no maintenance-dose efficacy estimate exists anywhere below 2.4 mg for an obesity population. The SUSTAIN diabetes programme did study 0.5 and 1.0 mg, but with glycaemic primary endpoints in people with type 2 diabetes, and weight figures from that setting do not transfer cleanly.

SELECT: the benefit that was measured at 2.4 mg

SELECT randomised 17,604 patients with overweight or obesity and established cardiovascular disease, and found a 20% reduction in major adverse cardiovascular events over a median 39.8 months, on semaglutide 2.4 mg weekly.

There is no low-dose version of that trial and no plan for one. Whether a fraction of the dose delivers a fraction of the benefit, all of it, or none of it, is unknown. For someone taking semaglutide primarily for cardiovascular risk rather than weight, that unknown is the whole decision.

Weight regain after stopping

The STEP 1 extension followed participants after semaglutide was withdrawn and documented substantial weight regain, with the cardiometabolic improvements reversing alongside it.

That finding is often used to argue for low-dose maintenance, and it is the strongest available argument, but notice what it actually establishes. It shows that stopping is followed by regain. It does not show that a reduced dose prevents regain, because the extension compared treatment with no treatment, not with a lower dose. The maintenance question has its own page.

Oral semaglutide changes the shape of the question

OASIS 4 reported 16.6% mean body-weight loss at 64 weeks under adherence with oral semaglutide 25 mg once daily, and about one in three participants lost 20% or more. Note the duration: 64 weeks, not 68, and it is an adherence-based figure.

For microdosing, the oral product matters because there is no microdose convention for it at all. A tablet is not an injector, the approved weight-management strength is a single 25 mg dose, and any content proposing a sub-25 mg weight-management regimen is describing something no label and no trial supports.

Safety items that do not shrink with the dose

Semaglutide carries a boxed warning for thyroid C-cell tumours. A personal or family history of medullary thyroid carcinoma or MEN 2 is a contraindication. Neither depends on how much you take.

Pancreatitis and acute kidney injury are recognised label risks. On 6 June 2025 EMA's PRAC classified NAION as a very rare side effect of semaglutide, up to 1 in 10,000 users, and recommended it be added to EU product information. Rare events at rare frequencies have not been characterised by dose, and there is no basis for telling anyone a microdose avoids them.

The evidence, one row per claim

Sources

1. STEP 1 / Novo Nordisk label schedule
2. Wilding et al., STEP 1 extension (PMC9542252)
3. Drugs@FDA record for NDA 218316 (Wegovy tablets, Novo Nordisk) via openFDA
4. European Medicines Agency, 'PRAC concludes eye condition NAION is a very rare side effect of semaglutide medicines', 6 June 2025
5. Systematic review of semaglutide thyroid carcinogenic risk
6. FormBlends (industry source; descriptive of practice, not evidence of efficacy)
7. American College of Cardiology, SELECT

Keep reading

• GLP-1 Microdosing: What the Term Means and What the Evidence ShowsThe term explained honestly: no regulator uses it, no trial tested it, and every dose-response curve in the fi
• GLP-1 Dose Chart: Label Schedules and Trial Dose-ResponseThe reference table: what each label says, next to what each trial measured, with no microdose column because
• Do GLP-1 Side Effects Improve at Lower Doses?Which adverse effects actually track with dose, and which categories a lower dose changes nothing about.
• Oral GLP-1 Options Compared: Orforglipron vs Oral Semaglutide 25 mgThe comparison people search for, with the honest caveat that nobody has run the trial that would settle it.