"A practical supplier guide to DL-Mandelic Acid (CAS 90-64-2, C8H8O3, EINECS 202-007-6): what this lipophilic alpha-hydroxy acid is, how it compares with glycolic and salicylic acid, its specification (white crystalline powder, mp 119-121 C, solubility 139 g/L, pKa 3.85, store below +30 C), its cosmetic and pharma/intermediate uses, and how it links to the glycolic/salicylic/azelaic/brightening cluster."
-Deshangchemical-chemechemi
DL-Mandelic Acid (CAS 90-64-2): The Lipophilic AHA That Exfoliates Gently and Fights Acne
DL-Mandelic acid is the racemic form of mandelic acid, also written as α-hydroxyphenylacetic acid. As a supplier, we list it under CAS 90-64-2, molecular formula C8H8O3, molecular weight 152.15, and EINECS 202-007-6. On the bench it is a white crystalline powder with a melting point of 119–121 °C and a density around 1.30 g/cm³. It dissolves in water at roughly 139 g/L and shows a pKa of 3.85 at 25 °C, which puts it in the same acidic range as the other alpha-hydroxy acids used in topical formulations.
What separates mandelic acid from the smaller AHAs is its structure. It carries a phenyl group, which makes it lipophilic rather than purely water-loving. That single change has practical consequences for formulators, and it is the reason mandelic acid keeps showing up in peels and leave-on products aimed at oily and blemish-prone skin.
Physical and chemical profile
The numbers below are the ones buyers actually check when they grade a shipment. They come straight from the product specification and are the same figures we quote on the COA.
| Property | Value |
|---|---|
| CAS number | 90-64-2 |
| EINECS | 202-007-6 |
| Molecular formula | C8H8O3 |
| Molecular weight | 152.15 |
| Appearance | White crystals or crystalline powder |
| Melting point | 119–121 °C (lit.) |
| Boiling point | 214.6 °C (estimate) |
| Density | 1.30 g/cm³ |
| Solubility in water | ~139 g/L |
| pKa | 3.85 at 25 °C |
| Specific rotation [α]D20 | -0.5 to +0.5° (c=2, H2O) — racemic |
| Storage | Store below +30 °C |
Because it is the DL (racemic) grade, the optical rotation sits near zero. Customers who need a single enantiomer for a specific synthetic route should say so up front, since the L and D forms are sourced and priced differently.
Why formulators pick mandelic acid over glycolic acid
Glycolic acid (CAS 79-14-1) is the smallest AHA and penetrates fast, which is exactly why it can sting. Mandelic acid is larger and oil-compatible, so it moves into the skin more slowly and tends to feel milder on sensitive or reactive skin. That trade-off — slower, gentler, still effective — is what makes it a common choice for in-clinic peels and for daily serums where the user cannot tolerate stronger acids.
The lipophilic side also helps it sit in sebum-rich areas. In practice this means it works where blemishes form: inside the follicle and along the sebaceous duct. It loosens the bonds between dead cells on the surface and, at the same time, shows antibacterial activity against Cutibacterium acnes (formerly Propionibacterium acnes). For a formulator, one raw material that both exfoliates and suppresses the acne-related bacterium is a tidy combination.
What it does in the finished product
The benefits that show up in marketing copy all trace back to those two actions — surface renewal and antibacterial control:
- Exfoliation. It removes the layer of dead cells that makes skin look dull and rough, which is the baseline job of any AHA.
- Pore cleaning. Its penetration lets it reach the debris and oil trapped below the surface, so products feel like they are actually doing something rather than sitting on top.
- Cell renewal. By clearing the old layer, it signals the deeper skin to bring fresh cells up, which is the mechanism behind the "smoother" claim.
- Brightening. As the thickened stratum corneum thins out, uneven tone and post-blemish marks look less obvious. For pigment work it is often paired with kojic acid (CAS 501-30-4) or alpha-arbutin (CAS 84380-01-8).
Mandelic acid is not the only acid used for this, and it is worth knowing the neighbours. Salicylic acid (CAS 69-72-7) is the classic BHA and is oil-soluble too, so the two are sometimes combined for a broader action. Azelaic acid (CAS 123-99-9) covers a similar acne-and-pigment lane, while capryloyl salicylic acid (CAS 78418-01-6) is the lipophilic ester form of salicylic used when a gentler, slower release is wanted. Knowing which one fits the formula is part of the brief we ask customers to send us.
Beyond cosmetics: the pharma and intermediate side
Mandelic acid is classified on our product page under four types — food additives, cosmetic raw materials, APIs, and organic raw materials — and the non-cosmetic uses are the part buyers undervalue.
As a chiral molecule, it is a useful building block in fine chemical and pharmaceutical synthesis. It appears in the route to cyclomannitate, a vasodilator, and its structure has made it a standard chiral intermediate for labs that need a defined stereocenter. Historically it was used orally as an antibacterial for urinary tract infections, a reminder that the same compound that smooths skin also has a documented antimicrobial track record. We mention this to show range, not to encourage off-label use; the cosmetic and intermediate grades are handled and documented separately.
How buyers should specify it
When you request a quote, the details that prevent a second round of sampling are:
- Grade. Cosmetic, food, or pharma/API — each has a different impurity and documentation bar.
- Assay and appearance. We typically ship white crystalline powder at the specification above; confirm the minimum assay your process requires.
- Microbiology and heavy metals. For leave-on cosmetic use these limits matter more than for an industrial intermediate, so set them early.
- Packaging. Mandelic acid stores below +30 °C and is stable in a sealed, dry container; we can pack to your requested size and label format.
For finished-skin routines, mandelic acid pairs well with a humectant such as urea (CAS 57-13-6) or an emollient like squalane (CAS 111-01-3) to offset any tightness, and with L-ascorbic acid (CAS 50-81-7) or citric acid anhydrous (CAS 77-92-9) where an antioxidant or pH-adjustment step is needed. A mild cleanser base such as sodium lauroylsarcosinate (CAS 137-16-6) rounds out an acne-focused regimen without adding harshness.
Sourcing from Chemechemi
We supply DL-mandelic acid as a white crystalline powder against the specification listed above, with COA, packing list, bill of lading, and origin certificate provided per batch. Every lot is tested before release, and we reply to inquiries within 24 hours so your formulation timeline does not slip. If you need the L or D enantiomer, a different particle size, or a specific document set for your market, tell us in the first message and we will quote accordingly.
Mandelic acid sits in a useful middle ground: more skin-compatible than the smallest AHAs, more directly antibacterial than most exfoliants, and versatile enough to serve both the cosmetic bench and the fine-chemical intermediate shelf. That combination is why it stays on our core raw-material list.
