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Some human trialsIn clinical trials

Cagrilintide side effects

Also known as: Cagri · Cag · Cagri peptide · NN9838 · NNC0174-0833

Updated 41 sources

10 side effects reported for Cagrilintide: 3 from studies and labels, 7 from users and guides. 5 come with the ways people manage them.

Cagrilintide overview

Side effects reported in studies and labels

Rates as each trial or label states them. A rate from one trial does not carry over to research-grade vials or other doses.

From trials and regulators3

Clinical studies and regulatory documents.

  • Constipation and diarrhoea

    Named among the most frequent adverse events in the phase 2 trial. The abstract gives no separate rates.

  • Stomach and gut side effects with CagriSema

    GI events in 79.6% vs 39.9% on placebo in REDEFINE 1, and 72.5% vs 34.4% in REDEFINE 2 (type 2 diabetes).

  • Stopping treatment because of side effects

    4% (30 people) across all phase 2 arms. With CagriSema in REDEFINE 1, 5.9% vs 3.5% on placebo, per press coverage of the results.

Side effects users and guides report

What people post and what dosing guides list. These are reports, not measured rates.

From users and guides7

Community reports, competitor and vendor guides, media.

  • Stomach and gut side effects (overall)

    GI adverse events in 41 to 63% on cagrilintide 0.3 to 4.5 mg vs 32% on placebo in the 26-week phase 2 trial.

    How people manage it

    • If stomach side effects are intense, step back to the previous dose until they settle.
    • Inject on a different day from your GLP-1 so the side effects do not stack on the same day.

  • Nausea

    Nausea in 20 to 47% on cagrilintide vs 18% on placebo in the phase 2 trial.

    How people manage it

    • If stomach side effects are intense, step back to the previous dose until they settle.

  • Injection-site reactions

    A dosing guide attributes 43% at 4.5 mg to the phase 2 trial; we could not confirm that figure. The trial abstract lists administration-site reactions among the most frequent.

  • Fatigue (dosing guide figure)

    A dosing guide attributes fatigue in 20% at 4.5 mg to the phase 2 trial; we could not confirm that figure in the abstract.

  • Fatigue and low energy

    The most common community complaint. In an r/cagrilintide poll of 40 people, 60% reported more fatigue, 37.5% no change and 2.5% more energy.

    How people manage it

    • Eat planned meals instead of skipping them; posters say this blunts the early tiredness.
    • Some report it fades after the first weeks; others stopped over it.
    • Some users switched to eloralintide citing less fatigue. That is anecdotal, and the eloralintide trial also reported fatigue.

  • Strong reaction to a first 0.25 mg dose on top of a GLP-1

    Community posts describe lethargy, bloating, constant burping and fewer bowel movements, and in one case vomiting and one meal a day for a week on semaglutide.

    How people manage it

    • Start lower when adding to an existing GLP-1. Posters often wish they had started at 0.125 mg, and many start at 0.1 to 0.25 mg.
    • Inject on a different day from your GLP-1 so the side effects do not stack on the same day.
    • If stomach side effects are intense, step back to the previous dose until they settle.

  • Eating too little and poor sleep

    Reported by one poster at 1 mg, who called that dose too strong.

    How people manage it

    • That poster dropped back to 0.25 to 0.5 mg in short add-on bursts.

How much is known

Some human trials

Cagrilintide alone: a 706-person phase 2 trial plus a monotherapy arm in phase 3 REDEFINE 1. CagriSema (with semaglutide): strong, from several phase 3 trials. With tirzepatide or retatrutide: no human data, only rat studies.

Sources for these side effects

14 sources, each checked by date. Record updated Oct 23, 2026. Numbers are restated in our own words and labelled by where they came from.

Competitor guide2

  1. Cagrilintide + Retatrutide Stack Guidepeptidedosingprotocols.com · checked Oct 23, 2026
  2. Cagrilintide Peptide Dosing Guidepeptidedosingprotocols.com · checked Oct 23, 2026

Community-reported8

  1. Cagrilintide & fatigue: the results are inr/cagrilintide · checked Oct 23, 2026
  2. Cagri fatigue: does it get better?r/Biohacking · checked Oct 23, 2026
  3. Anyone else starting to pay attention to (comment)r/GLP1ResearchTalk · checked Oct 23, 2026
  4. Stalling on 15mg tirzepatide (comment)r/Biohacking · checked Oct 23, 2026

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