Peptide Skincare & BeautySkin science and ingredient guides

Ingredient or product comparison

GHK-Cu Timing: Comparison of Dosing Windows

9–10 PM (optimal) Maximal (100% baseline) Direct overlap with 11 PM–2 AM GH pulse 100% reference standard Requires consistent sleep schedule 6–8 AM (suboptimal) Minimal (30–40% baseline) No overlap—GH nadir period 40–50% of evening dosing Convenient but wastes

This source-based comparison does not add ratings or recommend a winner.

  • 9–10 PM (optimal)
  • Maximal (100% baseline)
  • Direct overlap with 11 PM–2 AM GH pulse
  • 100% reference standard
  • Requires consistent sleep schedule
  • 6–8 AM (suboptimal)
  • Minimal (30–40% baseline)
  • No overlap—GH nadir period
  • 40–50% of evening dosing
  • Convenient but wastes half the compound
  • 12–2 PM (mid-day)
  • Low (50–60% baseline)
  • Partial overlap with minor afternoon GH pulse
  • 55–65% of evening dosing
  • Misses primary nocturnal repair window
  • 10–11 PM (late optimal)
  • High (90–95% baseline)
  • Overlaps tail end of GH pulse
  • 85–90% of 9 PM dosing
  • Acceptable if earlier dosing conflicts with schedule