Side effects
Foundayo side effects, dose by dose
The label gives the numbers strength by strength. Nausea was reported by 26 percent of people on 5.5 mg, 34 percent on 9 mg and 35 percent on 17.2 mg, against 10 percent on placebo. Constipation, diarrhea and vomiting follow the same climb. The label adds that nausea, vomiting and diarrhea were highest during escalation and decreased over time.
DM, the one who read the label
Sources checked Oct 7, 2026
Published Oct 11, 2026
Updated Oct 7, 2026 · 2 min read
The short answer
The label gives the numbers strength by strength. Nausea was reported by 26 percent of people on 5.5 mg, 34 percent on 9 mg and 35 percent on 17.2 mg, against 10 percent on placebo. Constipation, diarrhea and vomiting follow the same climb. The label adds that nausea, vomiting and diarrhea were highest during escalation and decreased over time.
What the label says
The Foundayo label does something the Wegovy tablet label does not: it reports side effects by strength. Table 1 pools the two placebo-controlled trials and lists everything that reached 5 percent, for people on 5.5 mg, 9 mg and 17.2 mg once daily, next to placebo.
| Reported by | Placebo | 5.5 mg | 9 mg | 17.2 mg |
|---|---|---|---|---|
| Nausea | 10 % | 26 % | 34 % | 35 % |
| Constipation | 9 % | 20 % | 27 % | 24 % |
| Diarrhea | 11 % | 21 % | 23 % | 25 % |
| Vomiting | 4 % | 13 % | 21 % | 24 % |
| Dyspepsia | 4 % | 12 % | 16 % | 13 % |
| Abdominal pain | 7 % | 13 % | 14 % | 14 % |
| Headache | 7 % | 8 % | 9 % | 9 % |
| Abdominal distension | 3 % | 7 % | 9 % | 8 % |
| Fatigue | 4 % | 6 % | 7 % | 9 % |
| Eructation | 1 % | 6 % | 8 % | 8 % |
| Reflux | 2 % | 6 % | 6 % | 7 % |
| Flatulence | 2 % | 5 % | 6 % | 6 % |
| Hair loss | 2 % | 4 % | 4 % | 5 % |
Taken together, stomach reactions of any kind were reported by 60 percent of people on 5.5 mg, 68 percent on 9 mg and 69 percent on 17.2 mg, against 37 percent on placebo. Stopping because of them: 3, 6 and 6 percent, against 0.7.
The sentence that matters most
From the labelThe incidence of nausea, vomiting, and diarrhea was higher during the FOUNDAYO dosage escalation period and decreased over time.
That is the label's own description of the curve: worst when a strength is new, better as the weeks pass. It is also the reason each step lasts at least 30 days.
What people actually do
The table matches what people describe, with one addition the numbers do not show: the first days of each new strength are the hardest, and the ninth milligram is where the jump is felt. People who keep a day by day note of how the stomach did find it easier to tell their prescriber whether a step needs more time, which is the decision the label leaves open.
Oolite's journal is two taps a day, kept by strength, so the pattern is on the screen at the next visit. Whether to hold a step or move on stays with the prescriber.
Questions people ask
Which strength has the most side effects?
In the label's table, the numbers rise from 5.5 to 9 mg and then mostly level off at 17.2 mg. Nausea: 26, 34, 35 percent. Vomiting: 13, 21, 24. Constipation: 20, 27, 24.
How many people stopped because of their stomach?
The label reports 3 percent at 5.5 mg, 6 percent at 9 mg and 6 percent at 17.2 mg, against 0.7 percent on placebo.
Are the side effects worse at the start?
Yes, by the label's own sentence: the incidence of nausea, vomiting and diarrhea was higher during the dosage escalation period and decreased over time.
Is hair loss on the list?
It is, at 4 to 5 percent versus 2 percent on placebo, at the bottom of the table. Fatigue is there too, at 6 to 9 percent versus 4.
Sources
- Foundayo prescribing information, Eli Lilly, §6.1, Table 1, revised 07/2026 · Adverse reactions in at least 5 percent of patients, pooled Trials 1 and 2, placebo N = 1,576, by strength 5.5, 9 and 17.2 mg; GI reactions 60, 68, 69 percent vs 37; discontinuation for GI 3, 6, 6 percent vs 0.7.
Sources checked Oct 7, 2026. This page is information, not medical advice: read the medical disclaimer, and talk to your prescriber or pharmacist about your own treatment.
Written by
DM, the one who read the label
I make Oolite. I read every label revision the day it comes out and rewrite these answers when they change.
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