This spiked my interest, so I looked around and found a 2018 paper (DOI: 10.1039/c7fo01715d) which, when fed into an LLM, gave me the following information (edited for brevity and clarity). Please note that I did not verify any of the LLM's claims, so take with a pinch of salt. Or pepper.

  The study tested a black pepper-based beverage (BPB) containing 20 mg gallic acid equivalent of polyphenols.
  
  Key findings:

  - Lowered hunger by 17%
  - Reduced desire to eat by 15%
  - Decreased prospective food consumption by 17%
  - Increased satiety by 14%
  - Increased fullness by 16%

  What didn't change:
  
  - Blood glucose and insulin responses
  - Gastrointestinal discomfort
  - Gut hormones (PYY and GLP-1)

  Approach:

  - The beverage was consumed 10 minutes before a meal
  - It contained water-extracted black pepper compounds (not piperine, which isn't water-soluble)
  - The extraction used hot water at 90°C for 3 minutes

  If you want to try this:

  1. Make a black pepper extract: Steep 20g of black pepper in 100ml of hot water (90°C) for 3 minutes, then strain and dilute with 900ml of water
  2. Timing: Consume about 10-15 minutes before meals
  3. Monitor your response: Track your appetite sensations to see if it works for you

  Critical notes:

  - The appetite-suppressing effects appear to be from water-soluble polyphenols (like apigenin and luteolin compounds), not piperine
  - The study was short-term, so long-term effects are unknown
  - Individual responses may vary
  - This won't affect your blood sugar or metabolism directly