There is a particular satisfaction in beginning something properly, and the 30ml Hirudin Serum was formulated with exactly that in mind. This is the size for those just starting their study of Hirudin & Co. — substantial enough to become a genuine part of an evening ritual, modest enough to feel like an invitation rather than a commitment.

At its center is our hero active: a rare, precision-formulated bioactive ingredient, the focus of decades of independent research, paired here with a small number of complementary botanicals chosen to support its texture and finish. On skin, the serum settles like silk pulled taut — weightless, fast-absorbing, leaving behind a soft luminosity rather than a film. With continued nightly use, skin begins to take on a visibly smoother, more refined-looking texture and a luminous, even-toned quality.

The 30ml size is housed in the same hand-finished amber glass as the rest of the collection, fitted with a brass dropper designed for precision — two to three drops is all the ritual asks for. It is formulated in small batches, independently tested for tolerability and stability, and intended as a quiet, deliberate addition to the closing hour of the day.

For those new to the collection, this is where to begin. For those returning to it, the 30ml is a considered companion to keep at a second vanity, in a travel case, or simply in reserve.