Lactic acid 90%

Lactic acid 90% in short

Lactic acid 90% is a liquid alpha hydroxy acid that dissolves in water, alcohol and glycerin. It is the stronger of the two lactic acid grades in our range. Because it is more concentrated, you need less of it to reach the same acid content as the 80% grade. The supplier CoA confirms the concentration of each lot. Note that a concentrated acid is strongly acidic; always measure the pH of your diluted premix and of the finished product yourself.

Why choose the stronger grade

Professional peel-style products and salon formulas often need a high acid content in a small volume. Starting from a 90% solution leaves more room in the formula for water, humectants and soothing ingredients. It also reduces the water you add with the acid, which matters in low-water products.

Product formats

Exfoliating serums

Leave-on serums aim at smoother, brighter-looking skin over several weeks. Choose the acid level and pH carefully, and test comfort with a panel.

Peel-style masks

Rinse-off masks used for a few minutes can carry more acid than leave-on products. Clear timing instructions on the pack are essential, and salon versions need trained staff.

Body care

Smoothing body lotions for rough skin on arms, legs and heels are a popular use.

Acid adjusting

A few drops of a diluted premix lower the pH of creams, gels and cleansers.

Handling and dilution

Wear gloves and eye protection. Add the acid slowly to water, never water to acid. Making a 10% premix in water first makes small adjustments easier and safer.

Formulating tips

Glycerin dissolves lactic acid well, and a glycerin premix can make serums feel more comfortable. Partial neutralization with sodium lactate or sodium hydroxide gives a buffered, gentler product. Choose thickeners that work at low pH, such as some cellulose gums or acid-tolerant polymers.

Partners

Lactic Acid 80% is the milder grade for everyday products. Glycolic Peel G25 25% can add another AHA in salon peels. Soothing ingredients like panthenol and allantoin add comfort. See more in our actives catalog.

Safety and labeling

Add clear directions and a patch-test suggestion.

Testing

Measure pH at each step and after stability tests. Check that packaging, including pumps and caps, resists acids. A sensory panel can rate tingling and comfort.

Claims

Use appearance wording: smoother, brighter-looking, more even-toned skin; soft, smooth skin on the body after regular use.

Characteristics

Form: liquid. Concentration: 90%, confirmed on the CoA. Solubility: water, alcohol, glycerin. Type: alpha hydroxy acid. Uses: exfoliating serums, peel-style masks, body care, acid adjusting.

Original recipe: overnight smoothing serum, 100 g

Distilled water 80.20 g, glycerin 6.00 g, lactic acid 90% 5.00 g, sodium lactate 60% 3.00 g, hydroxyethylcellulose 1.00 g, panthenol 1.50 g, allantoin 0.30 g, sodium PCA 50% 2.00 g, preservative 1.00 g. Hydrate the cellulose in water, add glycerin, then premixed acid and sodium lactate slowly, then the rest; check the pH.

Planning salon products

Salon peels need instructions for staff, a neutralizing or rinsing step and aftercare products. Prepare a short protocol sheet with each product and train staff before launch.

Documentation

Keep records of the acid level, final pH and test results for each product. Retailers and salons often ask for this data before listing.

Record the lot number in your batch log so every production run can be traced back to its certificate of analysis. Retain a small sample of each lot for at least the shelf life of the finished product, since it makes later quality questions much easier to answer.

Storage

Store tightly closed at room temperature in an acid-resistant container.