RP Strength Podcast Caffeine, Tolerance, and Getting Your Pre-Workout to Work Again with Dr. Eric Trexler
Mar 30, 2026
Dr. Eric Trexler, an exercise scientist who studies supplements and performance nutrition. He discusses why caffeine is so common in fitness. He talks about dosing by bodyweight, how tolerance and habituation reduce effects, timing and delivery forms like gum or pills, and practical strategies to resensitize use without wrecking sleep.
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Eric's Confession About Heavy Caffeine Use
- Eric Trexler admits he's a heavy caffeine user and calls himself a "hardened criminal" warning listeners not to follow him.
- He estimates his typical intake around 600–1000 mg daily and described packing caffeine capsules when traveling because he feared mornings without it.
Habituation Blunts Caffeine Gains And Research Is Sparse
- Habitual caffeine reduces its ergogenic effect over time (habituation), but doesn't necessarily eliminate it; withdrawal may impair performance relative to having no caffeine.
- Trexler highlights a lack of simple longitudinal studies quantifying how quickly and how much performance declines with chronic use and withdrawal.
Dose By Bodyweight Explains High Preworkout Caffeine
- Ergogenic caffeine dosing is usually expressed per kg bodyweight and the effective range is roughly 3–6 mg/kg.
- For an 80 kg person that means ~240–480 mg; doses above ~9–10 mg/kg often become ergolytic and harm performance.