The Safe and Effective Answer to Hyperpigmentation: 4-n-Butylresorcinol

Hyperpigmentation has a number of different causes, is triggered deeper in the Dermis and can be difficult and require a long term approach to treatment to treat.

There are 4 pathways through which topical depigmentation can be achieved:

  • Anti-oxidants: Eg. Vitamin C, which neutralise the signal created by UV exposure, to create melanin
  • Reduction of Melanin transfer: Eg. Vitamin B3 reduces the transfer of melanin (carried in melanosomes) to keratinocytes where it is deposited (as pigment)
  • Increased skin cell turnover: Eg. Glycolic acid and Vitamin A – flushes melanin in the skin
  • Tyrosinase inhibition: Eg. Hydroquinone (and 4-n-butylresorcinol) targets Tyrosinase, the precursor which is involved in creation of melanin.

While best results are available by targeting multiple pathways at the same time, Tyrosinase inhibition is the most effective pathway to tackle pigmentation. But it is also the slowest, with treatments often only starting to show results after 1 ½ to 2 months. That said, some depigmentation ingredients (like Vitamin A) can take 2 years to start showing results.

Not sure about the products for you? Take our Skin Quiz.

Of the Tyrosinase inhibition group, Hydroquinone is the “gold standard” ingredient , but it has for some time had a cloud over its safety profile and potential to irritate. The evidence for other ingredients in this group which includes Arbutin, Azelaic Acid, and Kojic Acid is not as strong as Hydroquinone, and these ingredients can be irritating and in the case of the Kojic Acid, also have some concerns around their safety. As a result there has been a significant amount of work done on alternate Tyrosinase inhibition ingredients in the search for one that is safe, well tolerated and effective.

A relative new-comer to this group is 4-n-Butylresorcinol – pronounced “4 N beautal resorcinol” – (a.k.a 4nB, 4 Butylresorcinol or Rucinol). The first study on 4nB was published in 1995, but it wasn’t until 2005 that another study was published, with the first trials on humans being published in 2007 . Since then, repeated human clinical trials have shown good results, low irritation, high tolerance and good safety results.

While there have been no head-to-head trials of 4nB and Hydroquinone the relative ability of common Tyrosinase inhibition ingredients to perform their core task has been studied. And when 4nB was compared to Hydroquinone, Arbutin and Kojic acid, it demonstrated superior tyrosinase inhibition ability.

Based on the evidence to date, in the search for an alternative to Hydroquinone, 4nB has been demonstrated to be the most effective depigmenting agent producing less irritation than the alternatives. But in the words of others taking into account its fast onset of action, once-a-day application, and a wide range of indications, this promising (4-n-Butylresorcinol based) product may be a revolution both in treatment of melasma and in skin rejuvenation.

Having found this, we created the Enlighten face cream (can be purchased individually or with a tailored kit) to specifically target hyperpigmentation and age spots using 4-n-Butylresorcinol. See how our Pigmentation Kit has improved the skin tone of customers:


A tyrosinase inhibitor (4-n-butylresorcinol) and antioxidant (Niacinamide) based cream to lighten and brighten skin appearance and provide a more even skin tone. Niacinamide provides visible improvements within 3 weeks. 4-n-butylresorcinol significantly improves outcomes after 2 – 3 months of continuous use.ESK-Enlighten



Follow us on social media or product highlights and exclusive content from Dr Ginni


Does improving the skin barrier function improve acne?
"Maskne" cutting through the BS to the Evidence

Invite & Earn

Signup to start sharing your link