Pimples: Can calendula help to reduce them?

Does calendula have effects on pimples?

The emergence of a pimple is a process involving three major factors: an increase in sebum production, an accumulation of dead cells on the skin surface, both of which can clog pores, and an increase in bacterial populations of Cutibacterium acnes, creating skin inflammation. To combat blemishes, many seek natural solutions, such as calendula macerate. Mainly known for its ability to soothe irritated or weakened skin, this ingredient could act on two characteristic factors of pimple formation, namely bacterial proliferation and skin inflammation. These potential actions of calendula would be made possible by its rich biochemical composition.

The oil macerate of calendula to limit bacterial proliferation?

The calendula oil macerate is believed to have interesting antimicrobial properties that can prevent and act against skin eruptions. A recent study examined the antibacterial action of a 30 mg/mL calendula extract against various bacterial cultures, such as E. coli, P. aeruginosa, B. cereus, S. aureus and K. pneumoniae. For this, the circular inhibition zone was measured, which corresponds to an absence of bacterial growth around the calendula extract placed in the center of the Petri dish. The more sensitive the bacteria is to the extract, the larger the inhibition zone. The various inhibition zones measured are presented below and were deemed comparable to those obtained for fluconazole, used as a control.

Bacteria	Circular inhibition zone (mm)
Escherichia coli	21 ± 2
Pseudomonas aeruginosa	19 ± 2
Bacillus cereus	15 ± 2
Staphylococcus aureus	18 ± 2
Klebsiella pneumoniae	16 ± 1

Characterization of the antibacterial activity of calendula extract by measuring circular inhibition zones for various bacteria.

The oil macerate of calendula demonstrated good antibacterial activity in this study, effective against both Gram-positive and Gram-negative bacteria. This property is believed to be due to its flavonoid content, compounds capable of halting bacterial growth by inhibiting the bacterial efflux pump, a membrane transporter that helps bacteria resist antibiotic treatments by allowing their expulsion from the bacteria. However, the antibacterial ability of calendula has not been tested against Cutibacterium acnes, which is implicated in the occurrence of pimples. Therefore, even though a similar mechanism of action can be assumed, additional studies are necessary for a complete understanding.

Calendula macerate to halt inflammation?

Beyond its antibacterial properties, the oil macerate of calendula is also believed to have anti-inflammatory effects, which can soothe redness and irritations associated with a pimple. The anti-inflammatory capacity of calendula has been demonstrated in numerous studies, conducted both in vitro and in vivo. Its mechanisms of action are manifold. Notably, the calendula macerate is capable of inhibiting certain pro-inflammatory cytokines, such as interleukins-1β and 6, tumor necrosis factor alpha, and interferon gamma, as well as the activity of cyclooxygenase 2, an enzyme that catalyzes the conversion of arachidonic acid into prostaglandin H2. These effects could be relevant in curbing the inflammation involved in the formation of certain pimples.

Thanks to its antibacterial and anti-inflammatory properties, the calendula macerate could help to alleviate some pimples. However, its action is limited as it does not act on excess sebum or the accumulation of dead cells, two key factors in their appearance.

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Concrete evidence of the action of calendula macerate on blemishes?

Although calendula shows promising results in reducing pimples, current clinical studies are scarce and do not solely examine this ingredient. However, one can be mentioned, conducted with 60 people suffering from inflammatory acne and focused on a herbal-based formulation, which among other things contained 8% calendula. The volunteers were divided into two groups: the first received the herbal-based cream while the second received a placebo, with instructions to apply it once a day for four weeks. The researchers evaluated several characteristics of inflammatory acne before and after treatment. While no significant difference between the groups was initially observed, the results show a significant improvement in the skin of the patients in the test group after four weeks, particularly in terms of the number of papules and overall inflammation.

Comparaison de caractéristiques de l'acné inflammatoire entre les groupes. — Comparison of inflammatory acne characteristics between groups.
Source: MALAYERI A. & al. Clinical trial of a herbal topical cream in the treatment of Acne vulgaris. American Journal of PharmTech Research (2012).

The application of the cream based on calendula appears to have had a significant impact on the participants' blemishes. However, it is important not to jump to conclusions about the effectiveness of the calendula macerate alone, as the studied formulation also included other ingredients, such as Rosa canina, Zataria multiflora , and Trigonella foenum-graecum. Therefore, it is challenging to precisely determine the effect of calendula. Additional research, focused solely on this plant, is necessary to confirm its action on blemishes.

The key takeaway.

The calendula macerate could prevent bacterial colonization, one of the triggering factors of pimples.
The calendula macerate could reduce inflammation and prevent the worsening of blemishes.
Clinical studies conducted on volunteers prone to blemishes and specifically targeting calendula are still needed to assert that this ingredient is an ally for skin with imperfections.