Natural L(+)-lactic acid (Alpha Hydroxy Acid)
Assay: 87.5-88.5% w/w
Description: Natural L(+)-lactic acid, which is produced by fermentation from carbohydrates.
Molecular formula: CH3CHOHCOOH
Molecular weight: 90
Chemical name: 2-hydroxypropionic acid
CAS number: 79-33-4 (general 50-21-5) USA GRAS
Solubility: comletely soluble in water and alcohol.
pH (approximate values! You must do your own pH test!):
100% : pH 0.6
10%: pH 1.90
5%: pH 2.15
3%: pH 2.20
1%: pH 2.40
You must use an alkaline pH adjuster to bring to pH UP to 3.5
Usage: Lactic acid and lactates can best be added in the aqueous phase.
The presence of lactic acid depends on the pH. The benefits and usage levels of lactates depend on the desired functionality:
pH-regulation: < 0.5%
Moisturizing: 0.5 - 5 %
AHA effect: pH 4.0 - 5.0
Skin lightening: pH 3.5 - 7.0
- Do not use more than 10%
- Final formulation pH no less than 3.5
- CTFA recommends the addition of an SPF for AHA formulations.
- Alternatively you MUST wear a HIGH UVA and UVB sun protection product
Storage: Cool, dry place. Do not freeze. Keep away from light and moisture!
Country of manfacture: Thailand
Manufacturer: Purac (CSM - The Netherlands)
Formulating with L(+)-lactic acid
Difference between L(+), D(-) and DL (racemic) lactic acid
Lactic acid is the simplest hydroxy acid with a chiral carbon atom. Due to this chirality lactic acid exists in a racemic form and in two optically active forms: L(+) and D(-). Only the L(+) form is the natural form and is present in the human body (e.g. skin, muscles and brain). Tests show that only the L(+) form is recognized by the skin, and that it also exhibits the least irritation. The D(-) form lacks some of the benefits of the L(+) form and the racemic mixture only partly possesses the benefits of the L(+) form. L(+)-lactic acid: the natural isomer of lactic acid.
Our L(+)-lactic acid is a 100% natural products, with carbohydrates (such as beet sugar) as their raw material. The production process (fermentation with the aid of bacteria) is also natural. In addition to L(+)-natural lactic acid, there is also so-called synthetic lactic acid available on the market. This product is less suitable for use in cosmetic formulations because it triggers irritation and is only 50% active. If lactic acid or lactates are to be used in cosmetic products, always insist on natural L(+)-lactic acid!
Lactic acid and milk
Because lactic acid (officially known as 2-hydroxy propionic acid) was first discovered in 1780 by the Swedish chemist Scheele in a sample of spoiled milk, it was named lactic acid. There is no other relation to milk and PURAC L(+)-lactic acid and lactates (sodium and potassium lactate) are clear, water white and low-viscous liquids with a mild odor. All other mineral salts are powders.
L(+)-lactic acid is very stable, resulting in a shelf life of 5 years. L(+)-lactic acid is a self-preserving acid so the product does not come under attack by micro-organisms. In most commonly used temperature areas (0°C/32°F to 200°C/392°F), L(+)-lactic acid is completely stable.
Regulating the pH
L(+)-lactic acid can be used to regulate the pH in all kinds of toiletry and skin care products. In liquid products, the addition of 0.1-0.5% wt of L(+)-lactic acid is, in most cases, sufficient to produce a pH of 5-6 in the end product.
Stabilizing products containing hydroxy acids and their salts can be a problem, since typical usage levels can be relatively high. This can result in a formulation that is very acidic and/or has high levels of salt (ions). Thickening systems such as Carbopol thickeners are therefore not compatible. Most thickeners however are compatible. These include xanthan gum.
Mild formulations for (sensitive skin and no risk of irritation) with L(+)-lactic acid
L(+)-lactic acid is very effective in producing mild formulations. Commercial products for sensitive skin and/or baby products often contain L(+)-lactic acid. In order to obtain such a mild formulation it is important to set the pH of the formulation at 5.5 - 7.0. If formulated at these pH levels, mild and gentle cosmetic products can be obtained that are suitable for all skin types.
Skin lightening properties of L(+)-lactic acid
The lightening properties of L(+)-lactic acid is are based on the suppression of the formation of tyrosinase. As a result, the lightening effect can be achieved at (skin) neutral pH conditions (pH 5.5-7.0).
Only a few active ingredients are currently known to have tyrosinase-formation suppression abilities. The best known active is L(+)-lactic acid and its salts.
Good skin-lightening properties have been reported at higher concentrations (>5% equivalent lactic acid), making use of the independent melanogenic controlling function of the viable pigment cell.
If formulated at lower pH levels, it is presumed that the exfoliative action of L(+)-lactic acid in some way could contribute to the lightening effects of the compositions tested.
Higher concentrations of lactates
It is possible to formulate with high concentrations of L(+)-lactic acid. Concentrations up to 15% have been reported in commercial products. The most important parameter to watch is the pH of the final formulation. As long as the pH of the formulation is higher than 5.0, mild and gentle products can be formulated with higher concentrations of L(+)-lactic acid.
Note that the final CIR report from June 1997 states that lactic acid is safe in concentrations =10% at a final formulation pH of = 3.5.
BulkActives' lactic acid is the natural form, L (+) Lactic Acid. Lactic acid is a naturally occurring alpha-hydroxy acid that is fermented from milk for use in cosmetics, lotions and cleansers to assist in smoothing and moisturizing the skin. Lactic acid is of great use in any healthy skin regimen, as it aids in the sloughing of dead skin cells, increasing cellular turnover while hydrating the skin for a fresh and rejuvenated complexion. Lactic acid can be used for many skin problems including the management of acne, wrinkles, psoriasis, keratosis pilaris and hyperkeratosis, and can even be used on slightly sensitive or allergy-prone skin.
Lactic Acid in Skin Care - Research:
Topically applied L Lactic Acid may:
Reduce fine lines and wrinkles: 
repair and treat sun damage:  
prevent and treat acne: 
lighten and brighten skin (treat melsama/hyper pigmentation): 
Side Effects of Alpha Hydroxy Acids
The two major side effects of alpha hydroxy acids are irritation and sun sensitivity. Symptoms of irritation include redness, burning, itching, pain, and possibly scarring.
People with darker colored skin are at a higher risk of scarring pigment changes with alpha hydroxy acids.
The use of alpha hydroxy acids can increase sun sensitivity by 50%!
Alpha hydroxy acids may be able to reverse some of the damage caused by photoaging, but at the same time they make the skin more susceptible to photoaging.
Anyone using alpha hydroxy acids must use a good sunscreen that contains UVA and UVB protection.
References (full abstracts here)
6. Smith WP. Epidermal and dermal effects of topical lactic acid. J Am Acad Dermatol. 1996 Sep;35(3 Pt 1):388-91. PMID: 8784274 [PubMed - indexed for MEDLINE]
5. Thueson DO, Chan EK, Oechsli LM, Hahn GS. The roles of pH and concentration in lactic acid-induced stimulation of epidermal turnover. Dermatol Surg. 1998 Jun;24(6):641-5. PMID: 9648571 [PubMed - indexed for MEDLINE]
4. Smith WP. The effects of topical l(+) lactic Acid and ascorbic Acid on skin whitening. Int J Cosmet Sci. 1999 Feb;21(1):33-40. PMID: 18505528
3. Rendl M, Mayer C, Weninger W, Tschachler E. Topically applied lactic acid increases spontaneous secretion of vascular endothelial growth factor by human reconstructed epidermis. Br J Dermatol. 2001 Jul;145(1):3-9. PMID: 11453900
2. Garg T, Ramam M, Pasricha JS, Verma KK. Long term topical application of lactic acid/lactate lotion as a preventive treatment for acne vulgaris. Indian J Dermatol Venereol Leprol. 2002 May-Jun;68(3):137-9. PMID: 17656910
1. Yamamoto Y, Uede K, Yonei N, Kishioka A, Ohtani T, Furukawa F. Effects of alpha-hydroxy acids on the human skin of Japanese subjects: the rationale for chemical peeling. J Dermatol. 2006 Jan;33(1):16-22. PMID: 16469079