Retatrutide
Triple incretin receptor agonist
An experimental peptide that acts on three hormone receptors. Researchers studied it in phase 2 trials involving weight and blood sugar.
PT-141
Also cited in the literature as Bremelanotide
A peptide that activates melanocortin receptors. Phase 3 trial results were published, and it was authorised for one use in the United States.
Regulatory status: Not licensed as a medicine in the United Kingdom. It holds no MHRA marketing authorisation and is not approved for human or animal use here, notwithstanding its authorisation in another jurisdiction.
Brain & nerve research
Research stage: Phase 3 results published; licensed for one condition in the United States
Cells
Animal studies
Human trials
The research pathway — not every compound has reached human trials. Illustrations are simplified, not study results.
What it is
PT-141, also called bremelanotide, is a laboratory-made ring-shaped peptide of seven amino acids. It was based on a natural hormone called alpha-MSH.
How researchers think it works
Studies found that PT-141 activated several melanocortin receptors. Researchers focused on the MC4 receptor in the brain as a possible explanation for the effects they measured.
What studies have found
- Two matching phase 3 trials, called RECONNECT, studied premenopausal women with low sexual desire that caused distress. Researchers reported changes in standard questionnaire scores compared with placebo.
- Nausea, skin flushing and headache were the most commonly reported side effects.
- The United States authorised the compound for that specific condition.
What we still do not know
- The trials relied on answers to questionnaires and studied one narrowly defined group.
- Published commentaries debated how meaningful the reported changes were in everyday life.
Sources
Related profiles
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BPC-157
Synthetic pentadecapeptide
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