Research · Single-study breakdown
An oral GLP-1 added to insulin: what the orforglipron trial actually showed
What this means for you
If you are on insulin and your A1c is still above target, this is an early look at a future option that would be a daily pill rather than another shot. In the trial it lowered blood sugar meaningfully and helped with weight — and it did not make low blood sugar worse, which is usually the thing insulin users worry about most when adding a second medicine.
The honest caveat: orforglipron is not FDA-approved for adding to insulin. This is trial evidence, not an approved label, so it is not something you can ask for today. It is a reason to ask your doctor what is coming down the pipeline, not a reason to change anything you are currently doing.
If you try it eventually, expect some nausea or other stomach upset early on, which is why the dose is raised slowly. Nothing here means you should adjust your insulin or any other medication on your own.
How the trial was run
ACHIEVE-5 was a phase 3, multicenter, randomized, double-blind, placebo-controlled trial run across 72 sites in the US, Brazil, China, Japan, and Romania. It enrolled 546 adults with type 2 diabetes whose blood sugar was inadequately controlled on titrated insulin glargine, many of them also taking metformin, an SGLT2 inhibitor, or both. Participants were randomized 1:1:1:1 to orforglipron at 3 mg, 12 mg, or 36 mg, or to placebo, all added on top of their existing insulin. Treatment ran 40 weeks, with the dose escalated gradually — starting at 1 mg and stepping up every 4 weeks to the assigned target.
At baseline the groups looked typical for this population: mean A1c of 8.50%, mean body weight of 85.2 kg, mean BMI of 30.8, and a median of 14.6 years living with diabetes. Of the 546 randomized, 507 (92.9%) completed the trial. Discontinuation was somewhat higher on orforglipron (13.3%) than on placebo (9.2%).
What the data showed
The primary measure was A1c change at week 40. Orforglipron lowered A1c by −1.58%, −1.88%, and −1.82% at the 3 mg, 12 mg, and 36 mg doses, compared with −0.79% on placebo. The treatment differences versus placebo — −0.78%, −1.08%, and −1.03% — were all statistically significant (P < .001). The two higher doses were the primary endpoint and the 3 mg dose a key secondary; all three beat placebo.
The proportion of participants reaching an A1c under 7.0% tracked the same way: 57% at 3 mg, 70% at 12 mg, and 65% at 36 mg, versus 25% on placebo. Body weight fell by −2.6%, −4.8%, and −5.4% across the three doses, against a slight gain of +0.2% on placebo.
Two patterns are worth naming. First, the A1c benefit roughly plateaus between 12 mg and 36 mg — going to the top dose bought very little additional A1c lowering — while weight loss kept increasing with dose. Second, and the reason this matters clinically: orforglipron did not increase the risk of clinically significant hypoglycemia compared with placebo. That is the question that matters most when you bolt a glucose-lowering drug onto insulin, and here the answer was reassuring.
What this study can't tell us
- 40 weeks is short — durability and long-term safety beyond about nine months are unknown.
- No head-to-head versus injectable GLP-1s such as semaglutide or tirzepatide, so we can’t say it matches those.
- GI side effects were the most common adverse events and contributed to some dropout; real-world tolerability may differ.
- Not FDA-approved for adding to insulin — this is trial evidence, not an approved label.
- Industry-funded (Eli Lilly), as most phase 3 drug trials are.
The analyst take: the headline isn’t the size of the A1c drop, which is in the range you’d expect from a GLP-1. It’s the delivery. Orforglipron is a nonpeptide, small-molecule pill taken once daily with no food or water restrictions. Almost every GLP-1 in wide use today is an injection, and the friction of weekly shots is a real barrier to both starting and staying on therapy. A pill that holds up in a phase 3 trial is meaningful for access and adherence in a way the raw percentages don’t capture.
Who is this for right now? Realistically, no one outside a trial yet — it is not approved for this use. It is most relevant to people already on insulin who are still above target and would rather not add an injection, and to the clinicians who treat them. The right move today is to watch where the regulatory process goes, not to act on a single 40-week study.
Sources
- Orforglipron Added to Titrated Insulin Glargine in Type 2 Diabetes (ACHIEVE-5) — JAMA (2026) · doi:10.1001/jama.2026.9512
- ACHIEVE-5 trial registration (NCT06109311) — ClinicalTrials.gov
Not medical advice. Educational summary of published research. Last reviewed Jun 7, 2026.