What backs us up.

We say: That an alkaline shampoo mistreats hair.

This rests on: Gavazzoni Dias and colleagues measured the pH of 123 shampoos and reviewed the literature on the subject. They write that alkaline pH can raise the negative electrical charge on the surface of the hair fiber and therefore increase friction between fibers. Above the isoelectric point of hair, which they place at 3.67, more water gets in, the cuticle lifts, and fragmentation and cracks appear. The authors conclude that a shampoo should not go above pH 5.5.

International Journal of Trichology, 2014. Open access.

We say: That sulfates are harsh detergents and that milder options exist.

This rests on: The mildness of a cleanser is measured with the zein test, which evaluates how much protein it manages to dissolve: the less it dissolves, the milder it is. The method is published as a protocol of the Joint Research Centre of the European Commission. Separately, the Cosmetic Ingredient Review panel documents the irritation profile of sodium lauryl sulfate, which is the reference irritant in dermatological patch testing.

EURL ECVAM DB-ALM, protocol 26 · Cosmetic Ingredient Review. Both open access.

We say: That vegetable oils behave differently on the hair fiber.

This rests on: How coconut, avocado and argan oils penetrate virgin and bleached hair, and how that depends on prior damage, has been characterized with tensile, fatigue and Raman spectroscopy testing.

Cosmetics, 2024. Open access.

We say: That skin also lives at an acidic pH, and that alkaline products affect it.

This rests on: Ali and Yosipovitch reviewed the literature on the skin’s acid mantle and place the physiologic pH of the stratum corneum between 4.1 and 5.8. They document that an alkaline pH compromises that barrier and favors the growth of unwanted microorganisms, the same kind of harm the literature describes for the hair fiber.

Acta Dermato-Venereologica, 2013. Open access.

We say: That our bars sit between pH 4.5 and 5.

This rests on: Our own measurement. It is not a third-party study: it is a figure from our formula, and we publish it because declaring pH is not required in Mexico and almost nobody does. The authors of the study above ask for exactly that declaration to be standardized.

We say: That this is why we formulate every bar to the pH of what it touches.

This rests on: Soap, by the way it is made, ends up alkaline. If alkaline mistreats the hair fiber and weakens the skin barrier, and our bars can be formulated within that acidic range, the decision makes itself. This conclusion is ours, not a study’s.

We say: That a bar with no water does not need the same preservatives as a bottle.

This rests on: Parabens are preservatives that stop microorganisms growing in products that contain water. Our bars contain no water. This is not a position on parabens: it is a consequence of the format.