Not medical advice. Talk to your provider before using any peptide.
Full disclaimerBryan Johnson's Tirzepatide Microdose (DISCONTINUED)
Three weeks, then done. Johnson tried tirzepatide at 0.5mg weekly (1/5th the standard starting dose) and halted when his data turned negative: resting heart rate up 3bpm, HRV down 7 points, sleep quality down 10%. He already had optimal metabolic markers, so the risk outweighed any benefit. This is some of the best-documented peptide discontinuation data available, with exact biomarker numbers attached.
Peptide Schedule Research TeamReviewed Apr 2026
A discontinued tirzepatide microdose protocol, documented here for the detailed adverse biomarker data Johnson published after stopping.
What This Protocol Does
Tirzepatide at 0.5mg weekly (1/5th the standard 2.5mg starting dose) for 3 weeks. Johnson tracked resting heart rate, HRV, and sleep quality throughout. All three metrics worsened: RHR increased 3 bpm, HRV dropped 7 points, and sleep quality declined 10%. He stopped at 3 weeks and published the exact numbers. This is one of the most data-rich peptide discontinuation reports available.
Who Should Use This
This protocol is discontinued. It's documented because Johnson published exact biomarker numbers that are hard to find elsewhere. If you're starting tirzepatide, this data provides a useful baseline comparison. Johnson already had optimal metabolic markers before starting, which may explain why the risk outweighed any benefit. People with metabolic dysfunction (high A1c, elevated fasting glucose) may respond differently since they have more room for improvement.
What the Research Says
Tirzepatide is FDA-approved for type 2 diabetes (Mounjaro) and obesity (Zepbound). The SURMOUNT-1 trial (Jastreboff et al., PMID 35658024) showed 22.5% weight loss at the 15mg dose in 2,539 participants. Standard titration starts at 2.5mg weekly. Johnson's 0.5mg dose (1/5th the starting dose) has no published clinical trial data. His cardiovascular metric changes (elevated RHR, reduced HRV) are not commonly reported in trials at standard doses, which may reflect individual sensitivity or the high baseline optimization of his health markers.
Important Notices
- DISCONTINUED after 3 weeks due to adverse biomarker changes
- Even at 1/5th standard dose, measurable negative effects on cardiovascular and sleep metrics
- Johnson already had optimal metabolic markers — risk outweighed benefit
Protocol Overview
Dosing Details
| Peptide | Dose | Frequency | Route | Weeks |
|---|---|---|---|---|
| 500mcg | Weekly | subcutaneous (abdomen) | Weeks 1-3 |
Tirzepatide: 0.5mg weekly. DISCONTINUED after 3 weeks: +3bpm RHR, -7pts HRV, -10% sleep quality.
Metrics Tracked
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Peptide Profiles & Calculators
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