active
Apple Cider Vinegar
The wellness-aisle ingredient that crossed into clean haircare via Ouai, dpHUE, and Briogeo. Acetic acid (4–7%) acidifies the scalp and cuticle, helps remove product buildup, and tightens the hair shaft for shine. Skincare use is more cautious — high acidity requires careful pH buffering.
Benefits
- acidic clarifying for scalp and hair cuticle
- removes product buildup and mineral residue
- fermentation-derived, low-controversy supply chain
Example uses
- clarifying hair rinses (Ouai)
- scalp pre-shampoo
- scalp tonics
Mechanism of action
The active fraction is acetic acid (4–7% w/v in raw ACV) plus minor amounts of malic and lactic acid, polyphenols, and pectin. On scalp, the low pH closes the cuticle scale by neutralising the alkaline residue left by surfactant cleansers and disrupts malassezia and bacterial overgrowth. On skin, acetic acid is a weak keratolytic at high concentration and a buffer-disruptor at moderate concentration. The 'mother' culture in unfiltered ACV contains acetobacter cellulose and trace probiotic-derived metabolites — interesting but cosmetically secondary to pH itself.
Clinical evidence · Anecdotal
Strong tradition and consistent user reports for scalp clarifying; near-zero controlled skincare RCT data. The mechanism (pH) is real; the cosmetic claims often outrun it.
Effective concentration range
5–15% in scalp rinses (pH 3.5–4); rarely above 2% on facial skin
Formulation notes
Diluted to pH 3.5–4 in scalp rinses. Filtered for clarity in cosmetic-grade ACV (raw 'mother' is preferred in DIY but problematic at scale).
Watchouts
Undiluted ACV is too acidic for scalp use. Skincare use above 2% can damage barrier; clean facial use is cautious or absent.
Controversies & overclaims
Undiluted ACV produces well-documented chemical burns when used as a 'natural toner' — a recurring problem in DIY-skincare TikTok culture. The wellness-aisle 'detox' framing has no dermatological basis. Dental erosion from oral overuse is a separate but related red flag for ingestion influencers who also promote it for skin.
Market positioning
Sold as a clean, pantry-grade clarifier — the wellness-to-beauty crossover poster child. Real cosmetic value is narrow: pH-resetting scalp rinses. Facial skincare positioning typically swaps in better-studied AHAs at controlled pH, dressed up in apple-vinegar marketing.
Comedogenicity
0 / 5
Sensitisation risk
Moderate
INCI & aliases
Pyrus Malus (Apple) Vinegar
acv · fermented apple cider · acetic acid
Clean beauty perception
Strongly positive in haircare; cautious in skincare.
Brands using Apple Cider Vinegar
Related ingredients
Graph relationships
Timeline