Lactose
molecular structure · PubChem
AKA: Milk sugar, CHEBI:17716, Beta-D-Gal-(1->4)-D-Glc, Beta-D-Galp-(1->4)-D-Glcp, (+)-Lactose, 1-beta-D-Galactopyranosyl-4-D-glucopyranose, Beta-D-galactopyranosyl-(1->4)-D-glucopyranose, Lactin, Anhydrous lactose
Synthetic
Humectant
Skin Conditioner
Not Clean
Lactose is a glycosylglucose disaccharide, found most notably in milk, that consists of D-galactose and D-glucose fragments bonded through a beta-14 glycosidic linkage. The glucose fragment can be in either the alpha- or beta-pyranose form, whereas the galactose fragment can only have the beta-pyranose form. It has a role as a human metabolite.
Solubility 50 to 100 mg/mL at 68 °F (NTP, 1992)
Formula
C12H22O11
Mol. Weight
342.30
CAS #
63-42-3
Form
Powder
State
Lactose is a white hard crystalline powder. (NTP, 1992)
Functions
Humectant
A moisture magnet. Pulls water from the air and deeper skin layers up to the surface to keep skin plump and hydrated.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Locks In Moisture
Traditional Use
Lactose, a naturally occurring milk sugar, has been used in traditional skincare preparations for centuries, particularly in Ayurvedic medicine for skin softening. Modern cosmetics use it as a humectant and skin-conditioning agent.
Skin Types
●all-skin-types
Best For
Dryness
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed1 review →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR