A spec sheet lists an acid by its initials and moves on, as if AHA, BHA and LHA were three flavors of the same ingredient. They are not. The letters describe where a hydroxyl group sits relative to a carboxylic acid, and that position changes how the molecule dissolves, where it distributes in skin, and which mechanism of desquamation it is built to drive.
A practice does not need the organic chemistry to run a protocol, but it does need enough of it to read a formulation sheet honestly, especially when LHA appears next to the more familiar AHA and BHA labels on the same page. Here is the distinction at the level it actually matters for evaluating what is in front of you.
AHA and BHA are defined by where the hydroxyl sits, not by what they do
An alpha hydroxy acid has its hydroxyl group on the carbon adjacent to the carboxylic acid, the alpha position. Glycolic and lactic acid are the common examples. They are small, water-soluble molecules, which means they partition readily into the aqueous, hydrophilic environment at the skin’s surface and into water-based vehicles.
A beta hydroxy acid has the hydroxyl one carbon further out, at the beta position. Salicylic acid is the reference compound. That structural shift makes the molecule meaningfully less water-soluble and more lipophilic than an AHA of comparable size, giving it affinity for the lipid-rich environment of sebaceous follicles and intercellular lipids rather than the aqueous surface layer.
The naming convention is structural, not a ranking of strength or a guarantee of a particular outcome. Knowing which letter is on the label tells you about solubility and likely distribution. It does not tell you a result.
LHA is a salicylic acid derivative, not a third parallel family
LHA, lipo-hydroxy acid, is commonly known in cosmetic chemistry as capryloyl salicylic acid: a salicylic acid molecule with a fatty acid chain attached. That makes it a derivative of the BHA family rather than an independent third category sitting alongside AHA and BHA as equals.
The added fatty chain is the entire story. It increases the molecule’s lipophilicity well beyond underivatized salicylic acid, which in turn is understood to slow its rate of diffusion across the skin and favor a more superficial, lipid-associated distribution. That combination, larger and more oil-affine, is the structural basis for describing LHA as a slower-acting, more lipophilic relative of salicylic acid rather than a different mechanism entirely.
This is a description of molecular behavior, not a measured outcome. No penetration depth, concentration or comparative speed is established here beyond the structural reasoning: a bigger, more lipophilic molecule moves through the barrier differently than a smaller, water-soluble one or than its own non-derivatized parent compound.
What the solubility difference changes about where each acid can act
Water solubility determines which compartment of the skin a molecule reaches first and stays in longest. An AHA’s affinity for the aqueous phase keeps it working at the surface, where it is associated with loosening the bonds between corneocytes. A BHA’s lipophilicity gives it a route into oil-rich areas that an AHA does not have on the same terms.
LHA’s added lipophilicity pushes that tendency further in the same direction salicylic acid already points, while the larger molecular size is the structural reason it is characterized as slower to diffuse. Slower diffusion and a lipid-associated distribution are the mechanistic basis for describing LHA’s desquamation as more gradual and more surface-restricted than an acid that moves through the barrier faster. That is a statement about chemistry, not a claim about comfort, downtime or result, which remain separate questions a mechanism description does not answer.
Where LHA sits in the LHALA Peel formulation
LHALA Peel, available in Basic and Ultra formats, combines LHA with INCUBE 504, H2sol and a lipid base. INCUBE is the MOF-based component built to adsorb and remove inflammation-inducing substances during peeling, which is the mechanism that anchors the product’s fourth-generation category label. H2sol is a separate active in the same formulation, currently a pending Korean patent application, not a granted patent, and should not be described as patented until that status changes.
LHA’s role in that combination follows directly from the chemistry above: a lipophilic, slower-diffusing salicylic derivative sitting alongside a lipid base and an adsorption-focused active, rather than an AHA brought in for a faster, more surface-level effect. That is a statement about which acid family is present and why it was likely selected for this kind of formulation, not a claim about what the combination accomplishes on skin.
What supports what. LHALA Peel Basic and Ultra each completed their own skin irritation test, 30 volunteers per format, non-irritant result for each. That is tolerance data, specific to those two formats, not an efficacy study of LHA, INCUBE 504 or H2sol individually or in combination. H2sol is a pending Korean patent application (KR 10-2024-0109462), with no grant identified; INCUBE’s underlying patents are granted to LabInCube and, for one of the two, Sookmyung Women’s University, not to LHALALA or H2MEDI.
Ask which acid family you are actually adding to the menu
An ingredient list that names LHA without explaining it as a salicylic derivative is asking a practice to take solubility and distribution on faith. The useful question for any peel under consideration is narrow: is this an AHA, a BHA, or a lipophilic BHA derivative, and what does that structural fact imply about where it is likely to act, independent of whatever the marketing language around it claims.
That question applies whether the acid in question is LHA or anything else on a competing spec sheet. If you want the testing status and the active breakdown for a specific LHALA Peel format before it goes on your protocol menu, the U.S. team can walk through what is on file and what is still pending.