Alpha-lactalbumin and sleep

What 7 graded rows on alpha-lactalbumin agree on for sleep, and where they differ. Counted side by side, never averaged.

Consensus finder Rows from the Alpha-lactalbumin page, reviewed Oct 21, 2026 How it decides

What the rows agree on

Each block and row is one graded row from the Alpha-lactalbumin page, with its PubMed record.

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Alpha-lactalbumin and sleep

7 rows · 118 people

Split. 3 rows found an improvement, 3 found no difference and 1 had mixed results.

No difference or mixed

Improved

Each block is one evidence row, sized by how many people it enrolled, with its grade inside. Outlined: mixed results.

Grade C× 1
Grade D× 4
No effect× 2

Rows: 7
Trials: 14
People: 118; Pooled reviews may count some twice

Where they differ

From the rows

The best-graded row, grade C, is a systematic review of 8 people (2024) and reported mixed results. 2 rows are graded No effect, our grade for adequately powered trials that found no effect.

By our six checks (size, design, length, who was studied, year and grade), the two sides do not differ cleanly. The dose and how each outcome was measured are in the rows below. 1 row with mixed results is left out of this comparison.

The rows

3 improved · 3 no difference · 1 mixed

Grade DSleep stages and next-morning reaction time in trained people with sleep difficulties · Improved
Crossover RCT · n 19 · 2025 · Trained adults with sleep difficulties
40 g/night · 3 consecutive nights per condition
Plasma tryptophan rose; stage 2 non-REM sleep increased (216.5 vs 205.9 min) and REM sleep decreased (99.7 vs 110.8 min), and morning reaction time improved on several cognitive tests (p<0.05).
Row on the Alpha-lactalbumin page · PubMed 39832504 (opens PubMed)
Grade DSleep-onset time across a competition season · Improved
RCT · n 18 · 2023 · Semi-professional female rugby union players
40 g/night · Nightly through a season; sleep measured in four 7-day blocks
Sleep-onset latency fell in the alpha-lactalbumin group in the bye week (23.3 to 11.6 min) and away-game week (to 17.0 min) but not in the home-game week; it stayed unchanged on placebo. The abstract reports a significant effect only for sleep-onset latency.
Row on the Alpha-lactalbumin page · PubMed 37077794 (opens PubMed)
Grade DSleep and recovery after evening competition · Improved
Crossover RCT · n 16 · 2021 · Trained women
One beverage after evening competition (dose not stated in the abstract) · Single nights
Stage 2 non-REM sleep rose after alpha-lactalbumin but fell after the controls, and Yo-Yo test distance improved over 24 hours compared with both controls.
Row on the Alpha-lactalbumin page · PubMed 34649262 (opens PubMed)
Grade DSleep and recovery in elite female athletes (wearable-measured) · No difference
Crossover RCT · n 21 · 2026 · NCAA Division I female athletes aged 18–25
40 g/night · 3 consecutive nights per condition
No condition changed total sleep time, sleep-onset latency, sleep efficiency, resting heart rate, heart rate variability, or subjective sleep and recovery compared with placebo.
Row on the Alpha-lactalbumin page · PubMed 42897977 (opens PubMed)
No effectHabitual sleep and performance in athletes with sleep difficulties · No difference
Crossover RCT · n 24 · 2025 · Athletically trained people with sleep difficulties
40 g/night · 7 nights
Awakenings rose slightly (11.0 vs 10.3), jump height fell slightly, and evening negative emotions fell; the authors conclude it may not improve sleep or performance.
Row on the Alpha-lactalbumin page · PubMed 40218954 (opens PubMed)
No effectSleep quality and 4-km time trial in cyclists · No difference
Crossover RCT · n 12 · 2020 · Trained cyclists in two small studies (6 each)
40 g · 1–3 evenings
No differences in time in bed, total sleep time, sleep efficiency or time-trial performance.
Row on the Alpha-lactalbumin page · PubMed 32698123 (opens PubMed)
Grade CSleep onset and sleep quality · Mixed
Systematic review, 8 studies · n 8 · 2024 · 8 studies in adults (4 in athletes, 4 in healthy people)
20–60 g, usually in the evening · Single nights to several nights
Five of eight studies found a positive association with sleep, mainly shorter sleep-onset latency after evening intake; none found a negative effect.
Row on the Alpha-lactalbumin page · PubMed 38185736 (opens PubMed)

Read onRead the full evidenceThe full evidence chapter on its page, with every outcome and its sources.