Is your GLP-1 dose really a microdose?

SURMOUNT-1 tested 5 mg, 10 mg, and 15 mg tirzepatide head-to-head. At 5 mg (the lowest therapeutic dose), average body weight loss was 15.0% over 72 weeks. The maximum approved dose of 15 mg showed 20.9%. This means the lowest therapeutic dose still delivers substantial results, only modestly less than the maximum. The starting titration dose of 2.5 mg was not tested as a long-term maintenance dose. (Source: Jastreboff AM et al. NEJM 2022;387:205-216)

The STEP 2 trial, which enrolled patients with type 2 diabetes, tested both 1.0 mg and 2.4 mg semaglutide against placebo. At 1.0 mg, participants lost an average of 7.0% body weight over 68 weeks, compared to 9.6% at 2.4 mg and 3.4% on placebo. The lower dose still produced clinically meaningful weight loss, but roughly half the effect of the full dose. For very low doses that online communities call microdoses (0.25-0.5 mg per week), there is no published long-term efficacy data, as these were designed as 4-week titration steps. (Source: Davies M et al. Lancet 2021)

The FDA prescribing information directs clinicians to increase from 2.5 mg to at least 5 mg after 4 weeks, with further increases based on tolerability and response. However, the label does not explicitly prohibit remaining at a lower dose. Some prescribers do keep patients at lower doses when side effects are limiting or when weight loss goals have been met. This is an off-label dosing decision made between patient and prescriber. The SURMOUNT-1 data showing 15.0% body weight loss at 5 mg gives clinicians a data point for shared decision-making. (Source: FDA Prescribing Information for Mounjaro and Zepbound)

The approved tirzepatide doses are 2.5 mg (titration only), 5 mg (lowest therapeutic), 7.5 mg, 10 mg, 12.5 mg, and 15 mg (maximum). In SURMOUNT-1, weight loss outcomes at each therapeutic dose were: 5 mg = 15.0%, 10 mg = 19.5%, 15 mg = 20.9% mean body weight reduction over 72 weeks. Community surveys (r/Zepbound, n approximately 800-1,200) suggest 15-25% of respondents report staying below their prescriber's escalation target. The most common reasons: side-effect management (45%), weight maintenance after goal (30%), cost reduction (25%). These are informal self-reported data, not clinical evidence. (Source: Jastreboff et al. NEJM 2022)

The titration schedule is designed to reduce gastrointestinal side effects by gradually exposing the body to increasing doses. For Wegovy (semaglutide), titration runs over 16 weeks before reaching the 2.4 mg maintenance dose. For Zepbound (tirzepatide), the starting dose is 2.5 mg for 4 weeks, then 5 mg, with optional increases every 4 weeks up to 15 mg. Microdosing refers to deliberately staying at a titration-level dose indefinitely because side effects of higher doses are intolerable, because a weight goal has been reached, or for cost reasons. Pharmacologically the two situations are identical; the difference is entirely in the clinical plan.

SURMOUNT-4 showed that after 36 weeks of maximum-dose tirzepatide, participants randomised to placebo regained an average of 14.0% body weight over the following 52 weeks. The STEP 1 extension study showed a similar pattern for semaglutide: participants who discontinued regained approximately two-thirds of their lost weight within one year. This weight regain occurs because GLP-1 agonists work by altering appetite signalling and gastric emptying; when the drug is removed, those effects reverse. (Source: Aronne et al. JAMA 2024; Wilding et al. JAMA 2022)

No clinical trial has specifically studied the safety of long-term sub-therapeutic dosing for weight maintenance. The titration doses were tested only for 4-week windows during dose escalation, not as sustained maintenance regimens. Some users report that staying at a lower dose significantly reduces nausea, diarrhoea, and vomiting, which are dose-dependent side effects. However, whether therapeutic effects on cardiovascular parameters and metabolic markers are maintained at sub-therapeutic doses is not well characterised. Any dose adjustment should be discussed with a prescribing physician. (Source: STEP 1-5 safety data; SURMOUNT 1-4 safety data)

No. This calculator provides population context, not medical advice. It shows where your current dose sits relative to the FDA-approved dosing schedule, the dose-response data from published Phase III clinical trials, and informal community-reported dose distributions. It does not account for your individual metabolic profile, comorbidities, side-effect tolerance, or treatment history. Dose decisions for GLP-1 receptor agonists should always be made in consultation with a qualified prescribing physician who can monitor your progress with blood work, weight tracking, and clinical assessment.