Can topical metronidazole treat acne and remove blackheads?

Recently, many friends have heard that metronidazole can remove blackheads. Is this true? What is metronidazole, what are its effects, and is it really effective in removing acne? Let's take a look!

Can metronidazole remove blackheads?

After the wet compress, blackheads and whiteheads can be easily removed. Isn't this too effective? Well, it is effective, but unfortunately it is not the credit of metronidazole.

Essentially, blackheads and whiteheads are oil that accumulates in the hair follicles and is not discharged to the surface of the skin. If the surface of the oil particle is covered with a layer of keratin, it is a whitehead; if it is not covered with keratin and directly contacts the air, 80% of the oil will be oxidized into black and become a blackhead. The newly secreted sebum is liquid at room temperature, and the sebum that cannot be discharged will often increase its melting point due to oxidation, that is, it will solidify into hard particles embedded in the pores and can be felt by hand. They are not infected by Propionibacterium acnes (one of the causes of acne), so they will not turn red.

Let's first look at what the original author did before cleaning the blackheads: prepare metronidazole solution, apply wet compress for two hours, and take a bath. During the wet compress and bathing process, the water content of the stratum corneum will increase, and the skin temperature will rise at the same time. The most direct effect of the increase in skin temperature is that the oil particles that are solidified and stuck in the pores will melt into liquid and be discharged to the surface of the skin through the opening of the hair follicles. Even if it is not completely melted, it is no longer stuck firmly and can be easily cleaned out under the action of external force. The stratum corneum has a high water content and will loosen over time. In layman's terms, "the skin is softened by soaking." It is not tightly bonded to blackheads or whiteheads, which is also conducive to external force cleaning. As for this external force, it can be a nail scraper, an acne needle, or a nose patch. Regardless of which is better or worse, the principle is the same.

Metronidazole is an antibiotic that targets anaerobic microorganisms (for example, it is used to treat intestinal and extraintestinal amebiasis, vaginal trichomoniasis, balanitis, skin leishmaniasis, and guinea worm infection, etc.), and is not effective against blackheads or whiteheads that are not related to infection. In other words, the effect of "all the blackheads and whiteheads on the nose and chin can be removed by scraping with fingernails" in the rumor on Weibo is only related to wet compresses and bathing, and has nothing to do with metronidazole.

Regardless of the purpose, wet compress is not recommended. Excessive water retention for a long time will damage the stratum corneum, reduce the skin barrier function, and cause more skin problems.

Does Metronidazole cure acne?

Acne is actually a type of acne. Depending on the severity of the disease, acne can be divided into several different stages. Blackheads and whiteheads are called "acne", and papules, pustules and even nodules caused by bacterial infection are usually called "acne".

The three main factors that cause acne are: excessive sebum secretion, adhesion of keratin in the funnel of hair follicles, and proliferation of acne bacteria. The overly thick stratum corneum covers the opening of the hair follicles, preventing the smooth discharge of sebum, which becomes a nutrient for acne bacteria. Acne bacteria decompose sebum into free fatty acids, which stimulate the hair follicles and cause inflammation. Controlling any one or more of these three factors can improve the acne situation.

As an antibiotic targeting anaerobic bacteria, metronidazole can theoretically inhibit the reproduction of Acnecae and reduce free fatty acids, so it seems feasible to use topical metronidazole to treat acne. But in reality, for various reasons, doctors rarely let patients use the drug in this way. Doctors prefer non-antibiotic topical drugs. If they are ineffective or difficult to tolerate their side effects, they will use topical or oral antibiotics, such as erythromycin and tetracycline.

But at the same time, the problem also lies with antibiotics. Long-term use of a certain antibiotic will inevitably make bacteria resistant to it. As an antibiotic that has been used very widely for many years, the drug instructions for metronidazole injection have already stated that "Propionibacterium is resistant to this product." If you want to treat acne caused by Propionibacterium acnes, it may disappoint you.

Therefore, metronidazole is not recommended for treating acne. There are better ways.

The polyphenol-refreshing acne-removing combination is divided into polyphenol-refreshing herbal tea and polyphenol-refreshing vitality tablets. What are their functions? The internal-regulating herbal tea is the "commander" that regulates endocrine and controls oil, and inhibits the vigorous secretion of oil through internal regulation; the external-use polyphenol-refreshing vitality tablets are the "cleaner" that accelerates skin metabolism, and by enhancing the activity of skin EGF, timely dredges pores and garbage, remove acne and acne marks at the source, and acne will no longer recur.