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αs1-Casein Hydrolysate (Lactium / casein decapeptide)
A milk-derived bioactive peptide — a tryptic hydrolysate of bovine αs1-casein standardized to the decapeptide α-casozepine (Lactium) — marketed for stress, anxiety, and sleep. Honest appraisal: the mechanism is real and food-derived (α-casozepine binds the benzodiazepine site of the GABA-A receptor in vitro), and a handful of small human RCTs show modest reductions in stress symptoms and cortisol plus some sleep-diary improvements. But several trials are industry-linked, two well-designed sleep RCTs were null on their primary endpoint, and effects are small. Well-tolerated; this is an ordinary dietary supplement, not a drug.
What the evidence says
Most Casein Hydrolysate studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 2001–2024 with a typical study size of 63 participants.
Based on 11 studies · 7 RCTs · 458 total participants
Confidence
ModerateBy outcome
Casein Hydrolysate has an evidence score of 4/10 — emerging evidence based on 11 indexed studies. A milk-derived bioactive peptide — a tryptic hydrolysate of bovine αs1-casein standardized to the decapeptide α-casozepine (Lactium) — marketed for stress, anxiety, and sleep. Honest appraisal: the mechanism is real and food-derived (α-casozepine binds the benzodiazepine site of the GABA-A receptor in vitro), and a handful of small human RCTs show modest reductions in stress symptoms and cortisol plus some sleep-diary improvements. But several trials are industry-linked, two well-designed sleep RCTs were null on their primary endpoint, and effects are small. Well-tolerated; this is an ordinary dietary supplement, not a drug. Representative study: PMID 28218661.
The commonly studied dose of Casein Hydrolysate is 150 mg/day of standardized αs1-casein hydrolysate (Lactium), taken once daily; acute studies have used ~200 mg. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
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Last reviewed June 2026 · evidence from 11 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
A plausible food-derived GABA-A mechanism and several small RCTs show modest stress/cortisol and some sleep benefits, but effects are small, trials are partly industry-linked, and two combination sleep RCTs were null — keeping it emerging.
Casein hydrolysate in the stress/sleep context refers specifically to a tryptic enzymatic digest of bovine αs1-casein (milk protein) standardized to contain α-casozepine — a 10-amino-acid peptide (residues 91-100 of αs1-casein) sold under the brand Lactium.
Unlike whey or casein protein powders taken for muscle, this is a low-dose (~150 mg/day) bioactive-peptide ingredient taken for its calming properties.
The mechanism is genuinely food-derived: in the original 2001 characterization, α-casozepine showed benzodiazepine-like activity and affinity for the GABA-A receptor benzodiazepine site, and animal work shows oral αs1-casein hydrolysate increases sleep duration and modulates GABA-A receptor subunit expression.
Human evidence is modest. The most-cited positive trials are a 30-day double-blind crossover in 63 stressed women (150 mg/day reduced several stress-symptom domains) and an acute study in healthy volunteers showing blunted blood-pressure and cortisol responses to laboratory stress.
Sleep results are mixed: one crossover RCT in poor sleepers found improved sleep-diary measures and actigraphic sleep efficiency, but two more recent placebo-controlled trials of Lactium-containing combination products were NULL on their primary sleep endpoints (with only secondary sleep-diary signals).
A notable confound is that several of these trials were funded by or co-authored with the manufacturer (INGREDIA / Ingredia SA).
Taken together the evidence is best described as emerging-to-low-moderate: a plausible, food-derived anxiolytic mechanism with several small, partly industry-linked RCTs showing modest stress/cortisol/sleep effects.
It is well-tolerated and, being a milk-protein fraction, is a normal dietary supplement — the main caution is milk allergy.
The decapeptide α-casozepine shows benzodiazepine-like activity and affinity for the benzodiazepine binding site of the GABA-A receptor in vitro — the proposed basis for its calming, anxiolytic-like effect (a food-derived 'natural benzodiazepine-like' action, far weaker than a drug).
In rodents, oral αs1-casein hydrolysate increases sleep duration, shifts EEG toward slow-wave/theta activity, and elevates GABA-A receptor β1-subunit expression in the hypothalamus — supporting a GABAergic, sleep-promoting action.
How Casein Hydrolysate works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
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150 mg/day of standardized αs1-casein hydrolysate (Lactium), taken once daily; acute studies have used ~200 mg
Can be taken without food
| Form | Type |
|---|---|
| 💊αs1-Casein hydrolysate standardized to α-casozepine (Lactium) | Recommended |
| 💊α-Casozepine (Zylkene — marketed for pets) | Alternative |
Lactium is the human-trial-grade ingredient. Generic 'casein hydrolysate' protein products are not standardized to α-casozepine and should not be assumed equivalent.
Minimum: 2 weeks
Optimal: 4 weeks
Cycling: Not required
Note: Once daily; evening/before-bed for sleep, daytime for stress reactivity. Trials used 150 mg/day (chronic) up to ~200 mg (acute).
Dose-response data unavailable. The current published research for Casein Hydrolysate does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Lower stress-symptom scores (digestive, cardiovascular, emotional, social, intellectual domains) over 30 days at 150 mg/day in a crossover RCT in stressed women.
Smaller rises in blood pressure and cortisol during laboratory stressors (Stroop + cold-pressor) in healthy volunteers.
Improved subjective total sleep time, sleep efficiency, and wake-after-sleep-onset in some trials — but two combination-product RCTs were null on their primary sleep endpoints.
Polysomnography and group-level insomnia scales often show no significant between-group difference; benefits, when present, are mainly on subjective/actigraphic measures — though one ACH-monotherapy RCT did find a significant PSG reduction in sleep-onset latency.
As a milk-protein fraction at low dose, it is generally well-tolerated with adverse-event rates similar to placebo in trials.
Avoid — it is derived from bovine milk casein.
As a normal food-protein component it is likely safe, but dedicated pregnancy trials are lacking — use under guidance if desired.
Use caution due to the theoretical additive calming effect.
Theoretical additive sedation given the GABA-A benzodiazepine-site mechanism, though the effect is far weaker than a drug; use caution if combining with prescription sedatives.
Possible mild additive calming/sedative effect; no clinically significant interaction documented.
Tip: Take in the evening; reduce dose
Tip: Take with food
The best time to take Casein Hydrolysate is in the evening. It can be taken on an empty stomach. For sleep/relaxation, most trials dose once daily; an evening or before-bed dose is common when the goal is sleep, while daytime dosing has been used for stress reactivity.
Casein Hydrolysate is generally well-tolerated and considered safe for most healthy adults at recommended doses. The most commonly reported side effects are mild drowsiness, mild GI discomfort. Use caution if any of these apply to you: Milk / dairy protein allergy (it is a bovine milk-protein fraction).
Reduces cortisol and anxiety while improving sleep quality and physical recovery in stressed adults.
Human trials report blunted cortisol and blood-pressure responses to acute stress and lower serum cortisol over weeks, consistent with dampening of HPA-axis stress reactivity.