Lactalbumin

ProteinBest before bed

What is it

Lactalbumin (primarily alpha-lactalbumin) is a small, tryptophan-rich whey protein found in human and bovine milk. It is the major whey protein in human breast milk and is used in supplement form for protein, sleep support, and as an infant formula ingredient.

Evidence for 3 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Sleep quality / stress response

Good Evidence

Multiple small RCTs in stress-vulnerable individuals show modest improvements in sleep quality and alertness on waking after evening alpha-lactalbumin consumption.

Muscle protein synthesis

Good Evidence

Complete, highly bioavailable protein supporting muscle synthesis comparable to other quality whey fractions.

Infant nutrition

Good Evidence

Alpha-lactalbumin-enriched infant formulas demonstrate better tolerability and growth outcomes closer to breast-fed standards than standard whey-casein formulas.

How it works

Alpha-lactalbumin is exceptionally rich in tryptophan (~6% by weight), the precursor to serotonin and melatonin. When consumed, especially without competing large neutral amino acids, it can increase brain tryptophan availability, supporting sleep, mood, and stress regulation. Lactalbumin is also a complete, highly bioavailable protein with excellent BCAA and total essential amino acid content for muscle protein synthesis and overall protein nutrition. In infants, it supports lower renal solute load and a protein profile closer to breast milk.

Dosage

For sleep/stress support: 10-40 g/day, often in the evening. For protein/muscle support: 20-40 g per serving as part of total daily protein intake.

When and how to take it

WHEN: Evening for sleep/stress support (1-2 hours before bed). Around exercise for protein synthesis. HOW: Mix with water, milk alternative, or beverage.

3 commercial forms

Compare the main delivery options and what they’re best suited for.

Alpha-lactalbumin isolate

Primary form for sleep/stress applications.

Most concentrated form

Alpha-lactalbumin-rich whey peptides

Sports nutrition and clinical use.

Pre-digested for absorption speed

Hydrolyzed lactalbumin

Used in protein-sensitive populations.

Faster absorption

Safety

Generally well tolerated. As milk-derived, avoid in cow's milk allergy. Lactose is minimal in purified isolates.

Who should be cautious

Avoid in cow's milk allergy. Use cautiously with serotonergic medications. PKU patients should verify phenylalanine content.

Interactions

Theoretical additive effect with serotonergic medications (SSRIs, MAOIs) due to tryptophan content; rarely clinically significant at dietary doses. May affect absorption of medications taken simultaneously with high-protein meals.

Food sources

Whey protein concentrate/isolate

Amount
Variable
%DV
—

Cow's milk

Amount
1 cup contains ~0.7-1 g whey proteins
%DV
—

Human breast milk

Amount
Major whey protein
%DV
—

Frequently asked questions

Does alpha-lactalbumin make you sleepy?⌄

It can support sleep quality when taken in the evening, particularly in people with stress-related sleep issues. Effects are modest, not sedating like a sleep drug.

Is alpha-lactalbumin better than regular whey protein?⌄

For sleep/stress applications, the higher tryptophan content provides advantages. For muscle building, regular whey protein works well and is more affordable.

References

Lactalbumin on Wikidata — Wikidata link

Lactalbumin on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Lactalbumin (PubMed search) — PubMed link

Track Lactalbumin with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.