4-Butylresorcinol

This laboratory-produced phenolic molecule is a targeted inhibitor of the enzyme tyrosinase. It is used in cosmetics at low concentrations, as it is effective even at tenths of a per cent. It is sensitive to oxidation and requires a suitable solvent system, protection from light and a carefully adjusted pH.

4-Butylresorcinol blocks tyrosinase and the protein TRP-1, two important components of melanin production. It therefore helps reduce the intensity of melasma, sun spots and post-inflammatory hyperpigmentation. It does not remove pigment immediately or act as a bleaching pigment. Visible changes appear gradually as the epidermis renews itself. Daily protection against both UVA and UVB radiation is essential for lasting results.

It is particularly beneficial for pigmented, mature and acne-prone skin with post-inflammatory marks. It is also suitable for people looking for a targeted alternative to hydroquinone. Those with sensitive or reactive skin should introduce it gradually, as higher doses or combinations with acids may cause stinging, redness or a contact reaction.

In a randomised, double-blind study, a 0,1 per cent cream was applied to one half of the face in people with melasma. After four weeks, the melanin index on the treated side decreased significantly, and the product was well tolerated (Annals of Dermatology, 2010). Further clinical data showed a good response to a 0,3 per cent serum used for 18 to 24 weeks.

Typical cosmetic concentrations are approximately 0,1 to 0,3 per cent. The raw ingredient needs a suitable solvent system and antioxidants, as it may crystallise or change colour. Opaque packaging, stability testing and clear instructions on using SPF alongside it are recommended.

When using targeted active skincare, it is best to start gradually and avoid changing several products at once during the first few weeks. This makes it easier to distinguish the effects from irritation. Visible changes in texture or tone usually require several weeks of regular use. Daily SPF protection, gentle cleansing and a well-functioning skin barrier have a significant influence on whether the results are good and lasting.