The Caffy Blog

Caffeine, sleep & science

Short, source-backed guides on how caffeine really works — and how to get its upside without wrecking your sleep.

July 2, 2026 · 5 min read

How long does caffeine stay in your body?

Caffeine's half-life is about 5–6 hours — here's what that means for the coffee you drank this afternoon, and when it finally leaves your system.

June 30, 2026 · 5 min read

What time should you stop drinking coffee for better sleep?

A 2023 meta-analysis put a number on the old “no coffee after 2 p.m.” advice: stop about 8.8 hours before bed to protect your sleep.

June 27, 2026 · 4 min read

How much caffeine is in coffee, tea, espresso and energy drinks?

Espresso, drip, cold brew, green tea, Red Bull — a clear, source-backed comparison so you know what you're really drinking.

400mg / day

June 23, 2026 · 4 min read

Safe daily caffeine limits: how much is too much?

The FDA and EFSA agree on 400 mg a day for most adults — and 200 mg in pregnancy. Here's what those numbers mean in cups.

June 18, 2026 · 5 min read

How to cut back on caffeine without the headaches

Quitting cold turkey is why people fail. A gradual 1–2 week taper — plus an earlier daily cutoff — keeps withdrawal at bay.