What benefits does bakuchiol offer the skin?

• Bakuchiol has antibacterial activity.

  Another benefit of bakuchiol for acne-prone skin is its ability to inhibit the growth of C. acnes. Indeed, according to studies conducted in vitro, this active ingredient has an IC50 (50% inhibitory concentration) of 0.6 µg/mL, much lower than that of salicylic acid (27 µg/mL), which shows its ability to limit bacterial proliferation responsible for inflammatory acne lesions. For reference, IC50 denotes the minimal concentration leading to 50% inhibition of a bacterial population. Diffusion tests were also performed and the inhibition zone was measured: it was 37 mm with bakuchiol, compared with 12 mm for salicylic acid.

• Bakuchiol exhibits anti-inflammatory activity.

  Bakuchiol has anti-inflammatory activity and caninhibit cyclo-oxygenases (COX), pro-inflammatory prostaglandin enzymes. A study showed this compound has strong activity against COX-1 (IC50 = 14.7 µg/mL) and moderate activity against COX-2 (IC50 = 514 µg/mL). It reduces nitric oxide production, a pro-inflammatory mediator involved in the worsening of acne lesions. These anti-inflammatory effects of bakuchiol help lessen the redness associated with blemishes.

What do clinical studies show about bakuchiol’s effect on acne?

The effects of bakuchiol on blemishes have been confirmed in several clinical studies. One study compared four formulations: 1% bakuchiol, 2% salicylic acid, a combination of 1% bakuchiol and 2% salicylic acid, and a placebo. Sixty volunteers with acne applied one of these creams to the face twice daily for six weeks. Their efficacy was assessed using the Global Acne Grading System, used in clinical studies. The results, presented in the table below, show a significant decrease in the number of acne lesions, both inflammatory lesions (papules, pustules, nodules) and non-inflammatory lesions (open and closed comedones).

The efficacy of bakuchiol in reducing wrinkles has been demonstrated in several clinical studies. One study involved 44 subjects who applied a 0.5% retinol cream or a 0.5% bakuchiol cream each day for twelve weeks. At the end of the twelve weeks, a significant reduction in wrinkles was observed in participants from both groups, slightly greater in the retinol group. However, retinol was associated with more adverse effects: 20% of volunteers in that group reported skin flaking compared to 10% of the bakuchiol group.

Bakuchiol also reduces hyperpigmentation. It can act in several ways on the melanogenesis, the process of melanin synthesis. Bakuchiol can first inhibit the enzyme tyrosinase, which converts tyrosine into melanin. It also lowers the expression of proteins associated with melanogenesis, such as TRP-1 (tyrosinase-related protein 1) and TRP-2. These proteins are involved in later stages of melanin maturation and help stabilise the pigment within melanosomes, the organelles where melanin is synthesised.

In addition to affecting melanin production, bakuchiol influences its transport. It inhibits dendrite formation, these cellular extensions that allow melanocytes to transfer melanin to neighbouring keratinocytes, thus contributing to its diffusion at the skin surface. This inhibition is achieved through modulation of several cellular signalling pathways, including Rac/Cdc42/α-PAK, which is involved in cytoskeletal dynamics. Bakuchiol can interfere with primary cilium formation in melanocytes — a cellular structure involved in pigmentation regulation.

The study mentioned earlier, in which 44 participants applied a cream containing either 0.5% retinol or 0.5% bakuchiol each day for twelve weeks, also examined the impact of these treatments on pigmentation. The results showed a significant improvement in skin tone uniformity in users of both products.

Bakuchiol is known for its antioxidant action due to a chemical structure rich in phenolic groups. These groups give it the ability to neutralise reactive oxygen species (ROS), unstable molecules generated by UV exposure or pollution. When produced in excess, free radicals trigger an oxidation cascade that damages membrane lipids, structural skin proteins such as collagen and elastin, and cellular DNA. Bakuchiol can trap these free radicals before they attack skin molecules and regulate signalling pathways involved in ROS production, such as NF-κB and MAPK.

A study examined the antioxidant capacity of bakuchiol and compared it with that of vitamin E, a well-known antioxidant. The ability of these molecules to inhibit multiple free radical species was tested and their IC50 values were measured. The results are presented in the table below and show that bakuchiol has broad antioxidant activity against various free radical species.

Bakuchiol may support skin healing by exerting a positive effect on the extracellular matrix. The matrix, comparable to a scaffold for the dermis, consists of collagen, elastin, laminin and fibronectin. During the healing process, a remodelling of this matrix is necessary : new fibres form while metalloproteinases, enzymes such as collagenase and elastase, degrade existing structures. However, excessive activity of these enzymes can weaken forming tissue and impair skin healing. One study showed that bakuchiol could inhibit collagenase (IC50 around 0.1% w/w) and elastase (IC50 between 1 and 5 µg/mL). By limiting degradation of collagen and elastin, it favours a more stable environment conducive to dermal fibre regeneration.

Bakuchiol may protect the dermal structure during healing, but these promising in vitro effects require further clinical validation.

Bakuchiol may soothe mild skin irritation as it can modulate the production of certain pro-inflammatory mediators. Studies on murine macrophages activated by interferon-γ (IFN-γ) or bacterial lipopolysaccharide (LPS) show that bakuchiol reduces expression of inducible nitric oxide synthase (iNOS), a key enzyme in macrophage activation during inflammatory states. This decrease is attributed to bakuchiol’s inhibition of nuclear factor κB (NF-κB), a central mediator in the inflammatory cascade. When activated, NF-κB drives production of pro-inflammatory cytokines such as IL-6.

Moreover, studies conducted in vivo in rats have shown that bakuchiol application could reduce the formation of induced oedema, confirming its anti-inflammatory potential in a living organism. However, despite these promising results, no clinical trial has yet been conducted in humans to validate these anti-inflammatory effects on the skin. These findings call for caution and further clinical research.