L-Lactic acid (2-hydroxy propionic acid) (CAS 79-33-4) — Citrus Top to middle Note Fragrance Ingredient
L-Lactic acid (2-hydroxy propionic acid)
CAS 79-33-4
What Is L-Lactic acid (2-hydroxy propionic acid)?
L-lactic acid is a naturally occurring organic acid found in foods like yogurt and sourdough bread, and also produced by our bodies during exercise. In fragrances, it’s used in tiny amounts to add subtle sour or tangy nuances. While not a major scent player itself, it helps create realistic fruit and dairy notes in perfumes and body products.
Safety Profile
GENERALLY SAFEWhat Does L-Lactic acid (2-hydroxy propionic acid) Smell Like?
L-lactic acid presents a clean, slightly sharp sourness reminiscent of fresh yogurt or buttermilk at full concentration, though it’s rarely used neat in perfumery. At dilution, it contributes a subtle tang that can enhance fruity top notes – particularly berry and citrus accords – with a naturalistic fermented quality. Unlike harsher synthetic acids, its odor profile remains smooth and slightly milky in the dry-down, blending well with lactonic and musky bases to create skin-like warmth.
Chemistry, Properties & Perfumer Guide
The Chemistry
L-lactic acid (2-hydroxypropanoic acid) is the levorotatory enantiomer of this α-hydroxy acid, differing from its D-form counterpart in optical rotation and some biological interactions. While naturally produced via bacterial fermentation of sugars, fragrance applications typically use synthetic versions for consistency. Industrial production involves chemical synthesis from acetaldehyde and hydrogen cyanide followed by hydrolysis, or increasingly via bioengineering methods using genetically modified microorganisms for sustainable production.
Physical & Chemical Properties
| Boiling Point | 122 °C (at 15 mmHg) |
|---|---|
| Melting Point | 52-54 °C |
| Density | 1.206 g/cm³ (at 20 °C) |
| Solubility | Miscible in water, ethanol |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | As a modifier in fruit accords |
| Body Products | 0.5-2% | Up to 5% | For pH adjustment and subtle tang |
| Functional Fragrances | 0.01-0.1% | Trace amounts | To enhance freshness in detergents |
Classic Accords
Tip: Use in micro-doses with ionones to create nuanced strawberry effects without harshness.
Alternatives & Comparisons
Racemic mixture offering similar sourness at lower cost, though slightly less refined in odor profile.
Gentler acid with slower release, useful for extended-release sour notes in functional products.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted by IFRA – considered safe at all typical usage levels in fragrance applications.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safety in cosmetic applications at current use levels.
Sustainability
Increasingly produced via sustainable fermentation processes using agricultural byproducts as feedstock. Synthetic routes remain common but carry higher carbon footprint. Biodegradable and non-bioaccumulative, posing minimal environmental risk at fragrance usage levels.
Explore L-Lactic acid (2-hydroxy propionic acid)
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- PubChem Compound Summary for L-Lactic acid PubChem CID: 107689
- EFSA Panel on Food Additives (2015). Safety of lactic acid for use in foods. EFSA Journal 13(11):4241
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data error
