Why Black Garlic balances oily scalps.
Most scalp-care formulas for oily scalps lean on harsh sulfates or salicylic acid to strip sebum away. The result is a clean feeling for about six hours, then the scalp rebounds — and the cycle repeats. Aged black garlic offers a different approach.
A 30-day transformation
Fresh garlic is fermented for 30 to 45 days under controlled humidity (60–80%) and temperature (60–80°C). During fermentation, the volatile sulfur compound allicin — responsible for the sharp smell and bite of fresh garlic — converts into S-allyl cysteine (SAC), a stable, water-soluble antioxidant.
SAC is what makes aged black garlic interesting cosmetically: it has none of the volatile sulfur smell, and it stays stable in formulation for 24+ months at room temperature. That stability is what most botanical extracts cannot offer.
What it actually does on the scalp
Three documented effects, in order of clinical strength:
- Calms 5-alpha reductase activity locally. The enzyme that converts testosterone to DHT (the hormone implicated in oily scalp and sebum overproduction) is modulated by SAC at topical concentrations. This is not the same as oral 5-alpha-reductase inhibitors — it is a gentle, local effect.
- Antimicrobial against malassezia. The fungal species most associated with sebum-related dandruff is sensitive to SAC.
- Antioxidant. Free radicals from heat tools, hard water, and pollution degrade scalp lipids and trigger compensatory sebum production. SAC neutralizes them.
Why it pairs with white willow bark
Our No. 03 Black Garlic series pairs SAC with white willow bark, a botanical source of natural salicylates. Salicylates exfoliate the scalp at very mild concentrations — clearing sebum buildup and dead skin from follicle openings without irritating the way synthetic salicylic acid can.
Together, SAC modulates sebum production at the source, while willow bark clears the buildup that already exists. The result is a scalp that feels lighter for 36–48 hours instead of six.
How to use it
Two to three times a week, alternating with No. 01 Hyaluronic Acid on dry days for balance. Apply to the scalp first, work down through lengths, leave 1–2 minutes, rinse. For severe oily-scalp cases, the No. 03 Hair Mask once a week extends the rebalancing effect.
Most users report a noticeable shift within 2–3 weeks: longer time between washes, a calmer scalp, less mid-day flatness at the roots. Patience matters — fermented ingredients work gradually, not overnight.
Aged black garlic is one of the rare ingredients where traditional fermentation and modern cosmetic chemistry meet at the same answer. We think it is the most underused scalp ingredient in the category.