Peak vs trough

What peak and trough actually mean on your dose curve, why trough is the conservative reference, and how to time labs to capture each.

Peak and trough are the two points on your dose curve that most decisions hang on. Understanding what they are — and why one matters more than the other for safety — makes everything else about protocol design easier.

Definitions

Peak is the highest level you reach in a dosing cycle. For an intramuscular oil depot, the peak isn't immediately after injection — it takes time for the compound to release from the depot and saturate circulation. Depending on the ester, the peak can occur anywhere from a few hours to several days post-dose.

Trough is the lowest level you reach, right before the next dose. It's the point where the previous dose's contribution has decayed the most and the next dose hasn't been administered yet.

On the DoseCurve chart, peaks are the visible humps and troughs are the dips between them. The bigger the gap between peak and trough, the more "spiky" your protocol is.

Why trough is the conservative reference

Most clinical decisions anchor to trough rather than peak, for two reasons:

If trough is in range, peak almost certainly is too. Trough is the floor of your cycle. As long as you're not falling below your therapeutic minimum at the lowest point, you're spending the rest of the cycle above it.
Trough is more reproducible. Peak timing varies with ester, individual metabolism, and injection site. Trough is simply "right before the next dose" — easy to time, easy to repeat across draws.

The downside: trough doesn't tell you whether you're overshooting. For compounds with a narrow therapeutic window or where supraphysiological peaks cause side effects (high oestrogen, mood swings, sleep disruption), a peak draw is worth doing at least once early in a new protocol.

How draw timing is usually described

The actual timing of any blood draw is something a clinician orders. The conventions below are widely documented in clinical pharmacology references and are included here as background only:

Trough draw, weekly protocol: the morning of the next scheduled injection, before injecting.
Trough draw, every-other-day protocol: immediately before the next dose.
Peak draw, long ester (e.g. cypionate, enanthate): typically 24–72 hours post-injection; the modelled peak time on the chart corresponds to the half-life entered.
Peak draw, short ester or peptide: hours post-injection.

Recording the exact time of the most recent dose on the lab requisition is standard practice so the result can be interpreted in context.

The peak-to-trough ratio

The ratio of peak to trough is a single number that summarises how stable your protocol is. Lower frequency → bigger ratio → more variability. Higher frequency → smaller ratio → flatter curve.

A weekly cypionate protocol typically has a peak-to-trough ratio around 1.6–1.8. Splitting the same total dose into twice-weekly drops the ratio to roughly 1.2–1.3. Daily SubQ is close to 1.0 — essentially flat.

There's no universally "correct" ratio. People with stable mood and symptoms on weekly dosing have no reason to change. People who feel a clear crash before their next dose often benefit from splitting.

What the chart shows

DoseCurve labels both values directly: Peak, Trough, and the Average between them, calculated across your selected time window. If you set a therapeutic range (minimum and maximum mg), the chart also shades the band and reports Time in Range — the percentage of your window spent inside the target.

Time in Range is often a more useful single metric than peak or trough alone because it captures both at once. A protocol with 95% time-in-range is well-tuned regardless of where the individual peaks and troughs sit.

DoseCurve is an educational tool. Nothing on this site is medical advice. Always consult a qualified clinician before starting, changing or stopping any protocol.