# Lactium (alpha-s1 casein hydrolysate)

Milk-protein decapeptide for stress and sleep; gentle, non-sedating, slow to build.

- Page: https://peprank.xyz/peptides/lactium
- Category: Sleep (Supplement)
- Also known as: alpha-casozepine; bioactive milk peptides; casein decapeptide; Zylkene (the veterinary version)
- Routes: Oral
- Sequence: YLGYLEQLLR (representative: αs1-casein f91-100 (α-casozepine) within a casein hydrolysate mixture)
- Safety tier: Strict: Clean · Balanced: Clean · Evidence only: Clean
- Risk axes (0 none to 3 severe): Seen harm 0, Mechanism 0, Data gap 1, Silent harm 0, Product 0
- Positive: 52% of 11 graded reports glowing or positive, shrunk toward the 49% all-report average by 8 reports' weight
- Rank: #7 of 23 supplements
- Graded reports: 11 (Glowing 1, Positive 5, Mixed 3, Nothing 2)
- Evidence: Human RCTs — N of 36-63; on stress symptoms, blood-pressure response to stress and sleep; mixed objective results, and much of the trial base is manufacturer-linked
- Access: Supplement
- Onset: Some feel calmer within hours; trials and users describe the sleep effect building over 1-4 weeks.
- Lasts: Taken nightly or as needed; no carry-over once stopped.
- Cost per month: ≈ €12–23 (at 150–300 mg/day, iHerb at €2.59/g)
- Updated: 2026-10-30

## What users report

Few people talk about it, and the reports are short. Users who like it describe a quiet calm with no sedation, help getting back to sleep when stress or 'high cortisol' wakes them, and an effect that builds over a few days. Several of the warmest reports come from blends with jujube and hops, so Lactium's share of the effect is unclear. A minority feel nothing. A few relaxed users still wake more often or feel flat or crash in the afternoon, and one person could not tolerate it. Felt nothing: ~20% of reports; Reddit coverage is thin (about a dozen first-hand reports).

**Effects:** calmer under stress without sedation; easier to fall back asleep after night waking; builds over several days

**Downsides:** fragmented sleep or extra waking for some; afternoon fatigue or flatness at higher doses; many products are blends, so hard to judge alone; dairy-derived (milk allergy)

**Caveat:** Most trials are small, many were funded by the ingredient maker, and subjective sleep scores often improve as much on placebo. The veterinary version (Zylkene) is widely used for anxious pets, but owners' reports about pets are not first-hand evidence. A dairy protein with no safety signal in humans.

**Typical use:** 150-300 mg/day (trials used 150 mg for stress, 300-600 mg for sleep), at bedtime or split morning and night.

**Getting it:** Sold as Lactium (Ingredia) in stress and sleep capsules, e.g. Swanson 'Women's Anti-Stress', Life Extension 'Bioactive Milk Peptides' and Nature's Own Advanced Sleep, often blended with jujube, hops or L-theanine.

**Stacked with:** L-theanine (commonly paired for daytime calm; one trial tested the two head to head); jujube seed and hops (the Australian 'Advanced Sleep' blend behind the strongest report); magnesium glycinate (common bedtime pairing)

## Risk profile

- **Seen harm 0/3:** Small RCTs found it well tolerated and first-hand reports mention only fragmented sleep or daytime flatness.
- **Mechanism 0/3:** A milk-protein hydrolysate whose active decapeptide (alpha-casozepine) acts weakly on GABA-A receptors; no pathway to serious harm is known.
- **Data gap 1/3:** A dairy-derived ingredient with a 2004 US new-dietary-ingredient notification and several small RCTs (n=36-63), many maker-funded; EFSA assessed only its efficacy claim.
- **Silent harm 0/3:** Any effect is felt the same night or day and stops with the product.
- **Product 0/3:** OTC capsules from mainstream supplement brands, often in blends.
- **Never if:** Cow's milk allergy

## Top reports

- Glowing, sleep, 112.5 mg Lactium in a blend: “I take Nature's Own Advanced Sleep - best sleep of my life; deep, refreshing and uninterrupted with no hangover. Stuff is a deadset miracle for me and I have tried everything.” — [r/Supplements](https://www.reddit.com/r/Supplements/comments/s4w31x/best_supplement_that_helps_you_stay_asleep/hsuf8di/)
- Positive, anxiety: “While you're figuring it out, the 2 most helpful products I've found are [lactium]” — [r/Biohackers](https://www.reddit.com/r/Biohackers/comments/1ppqxc8/sick_of_being_tired_but_wireddoes_anything/nuopy7k/)
- Positive, sleep: “Check out Lactium, a milk peptide that helps with cortisol levels. Available from Swanson. Helps me a lot.” — [r/Supplements](https://www.reddit.com/r/Supplements/comments/sbyiil/need_something_for_falling_and_staying_asleep/hu4f2jk/)
- Positive, anxiety, three times a day: “I have tried it and it did help. My morning cortisol was in the normal range after using it.” — [r/Supplements](https://www.reddit.com/r/Supplements/comments/1e6gr7o/lactium_for_stressanxiety/lo1pqay/)
- Positive, sleep: “Other things that have helped me over the years are bioactive milk peptides, casein powder with warm milk, L theanine” — [r/Supplements](https://www.reddit.com/r/Supplements/comments/h0qc2h/magnesium_causing_trouble_in_sleeping/ftpq2pw/)

## Studies

- [Kim et al., Efficacy of alphas1-casein hydrolysate on stress-related symptoms in women (Eur J Clin Nutr 2007)](https://pubmed.ncbi.nlm.nih.gov/17136040/) (rct, n=63, 2007): Crossover: 30 days of 150 mg/day reduced self-rated stress symptoms (digestive, cardiovascular, intellectual, emotional, social) vs placebo; part-funded by the maker, Ingredia.
- [Messaoudi et al., Tryptic hydrolysate of bovine alphaS1-casein and hemodynamic responses to mental and physical stress (Eur J Nutr 2005)](https://pubmed.ncbi.nlm.nih.gov/15517308/) (rct, 2005): Three doses of 400 mg before a Stroop and cold-pressor test blunted the rise in blood pressure and lowered cortisol vs a milk-powder placebo.
- [Kim et al., Crossover trial of alpha-s1 casein hydrolysate on sleep disturbance (Nutrients 2019)](https://pubmed.ncbi.nlm.nih.gov/31252661/) (rct, n=48, 2019): Questionnaires improved equally on Lactium and placebo; sleep diaries and 4-week actigraphy favoured Lactium, polysomnography did not differ.
- [Chang et al., Alpha-s1 casein hydrolysate in chronic insomnia, randomized double-blind trial (Clin Nutr 2024)](https://www.clinicalnutritionjournal.com/article/S0261-5614(24)00397-2/abstract) (rct, n=36, 2024): 600 then 300 mg/day for 4 weeks shortened polysomnographic sleep onset by about 8 minutes vs placebo and improved one sleep-disorder score.
- [Thiagarajah et al., Alpha-S1-casein tryptic hydrolysate and L-theanine on poor sleep quality, crossover RCT (2022)](https://pmc.ncbi.nlm.nih.gov/articles/PMC8838692/) (rct, n=39, 2022): A Lactium plus L-theanine blend (RLX2) improved PSQI sleep duration and efficiency in poor sleepers; other gains held in only one of two analyses.

## Sources

- [Miclo et al., Characterization of alpha-casozepine, a tryptic peptide from bovine alpha(s1)-casein with benzodiazepine-like activity (FASEB J 2001)](https://pubmed.ncbi.nlm.nih.gov/11481228/)
- [Kim et al. 2019, full text (PMC)](https://pmc.ncbi.nlm.nih.gov/articles/PMC6682925/)