To choose medical-grade numbing cream correctly: Verify FDA/CE certification and check for 4-5% lidocaine concentration. Test a small area 48 hours before use—redness/swelling indicates allergy. Ensure packaging lists sterile manufacturing standards (ISO 13485) and expiration dates. Buy from authorized clinics/pharmacies; avoid products claiming “instant numbing” (safe options take 30-45 minutes). Monitor for adverse reactions (≤5% occurrence) like tingling beyond 2 hours.
Check the qualification certification
This matter needs to be detailed from the data. Last year, the State Food and Drug Administration randomly checked 37 anesthetic creams on the market that were labeled as “medical grade”. As a result, 23 of them had no medical device number registration at all – equivalent to 62% of the products running naked. A typical case is a certain Internet celebrity brand. The packaging says “Class II medical device”, but the registration certificate found in the system is actually “gynecological irrigator”. This operation of selling dog meat under the guise of sheep directly led to a 48% surge in consumer complaints last year.
What do you think is the most outrageous? Some merchants PSed the medical device number certificate that expired in 2018 into the 2023 version. As a result, professional counterfeiters used pixel analysis tools to find out that the font spacing deviation in the date column was 0.3 mm. Once reported, they were fined 500,000. Therefore, now you must check the dynamic data on the official website of the Food and Drug Administration. For example, in the catalog of anesthetic devices updated in March this year, it is clearly required that epidermal anesthesia products must be marked with “the error of the action time shall not exceed ±15%”. Those who claim to “last for 8 hours” but cannot produce clinical trial reports are all hooligans.
There is also an unpopular but fatal data: the “model specification” pit is hidden in the registration information of the medical device number. Last year, a hot-selling anesthetic cream said “suitable for laser beauty”, but the actual registration model was “TY-02B (for oral mucosa only)”. The direct consequence of the mismatched model was that consumers had 38 reports of skin ulcers when using it for hair removal. So now veterans have developed a habit of checking every comma in the filing information. For example, the risk level of “applicable to intact skin surface anesthesia” and “applicable to damaged skin” differs by more than three times.
Don’t think that imported goods are reliable. In 2022, the customs intercepted a batch of Korean-made anesthesia patches, claiming to be “KFDA certified”, but Chinese regulations require that imported medical devices must obtain an “Imported Medical Device Registration Certificate”. The actual customs clearance records of this batch of goods show that the declared product name is “Beauty Cold Compress Patch”, and the unit price of the goods is falsely marked from US$3/box to US$23. When it was investigated, the profit margin was as high as 657%. How to identify real imported goods? Look at the words “Guo Xie Zhu Jin” + 8-digit continued registration number on the Chinese label, such as “Guo Xie Zhu Jin 20235678”, one digit less can be fatal.
Recently, there was a trick of “certificate duplication”: a manufacturer used the same Class II medical device certificate to endorse 6 products with different ingredients, but was caught by the drug administration during a flight inspection. The regulations clearly stipulate that “one certificate, one formula”, and unauthorized changes to the proportion of auxiliary materials are considered unlicensed production. This incident directly led to a backlog of 17 million yuan in inventory when the brand was removed from the shelves, and the dealer return rate reached 89%. Therefore, now the verification not only needs to look at the certificate, but also the formula table in the “Product Technical Requirements” document. The pH range and viscosity index may fail if the difference is 0.1.
Teach you a wild way: Go directly to the “Medical Device Adverse Event Monitoring” column on the drug administration website. For example, if you enter “lidocaine gel”, you can see that there were 14 reports of burns in the second quarter of 2023, 11 of which involved unregistered products. What’s even more ruthless is the comparison of “first registration date” and “validity period” – a brand’s registration certificate shows that it was approved in 2021, but the instructions say “adopting the 2023 version of the EU standard”, which is obviously a fraud, because the registration information must be resubmitted when the medical device standard is updated, and this loophole is caught.
Check the ingredient list
Do you think the ingredient list is just for show? Last year, the Food and Drug Administration found that 41% of the anesthetic creams on the market had false ingredients. There was a popular product claiming to be “pure plant formula”, but liquid chromatography detected 2.8% lidocaine – this concentration is enough to send a three-year-old child to the emergency room. Even more outrageous is a certain WeChat business brand, which wrote benzocaine as “Benzocaine” and thought it could fool people. In fact, the “Nomenclature Rules for Common Names of Medical Devices” clearly stipulate that the Chinese ingredient name must be consistent with the “Chinese Pharmacopoeia”, and playing with English abbreviations is directly a violation.
Don’t underestimate the difference in concentration. In 2023, the Shanghai Consumer Association tested 18 anesthetic creams, of which 6 had actual lidocaine concentrations exceeding the labeled value by ±15%, with the highest deviation reaching 32% (labeled 4% but actually containing 5.28%). This excess directly caused the allergy rate to soar from the industry average of 7% to 29%. In one case, a girl used a certain online celebrity cream before tattooing her eyebrows, and her eyelids swelled like walnuts. Later, it was found that it contained 5% procaine, which has long been banned by the EU for epidermal anesthesia.
Here’s a tough trick: compare the “formula change record” of the product filing. Last year, a manufacturer secretly reduced the concentration of propylene glycol from 30% to 15%, causing the product penetration rate to plummet by 60%, and users complained that “it’s the same as not applying it.” Real veterans will stare at the “Product Technical Requirements” document on the official website of the Food and Drug Administration, where even the amount of preservative phenoxyethanol added is accurate to 0.01%, such as “methylparaben ≤ 0.2% (w/w)”, a difference of 0.05% may affect the anesthetic time.
The most insidious operation I have encountered is “ingredient substitution”. A certain brand replaced lidocaine with cheap tetracaine. Although both are anesthetics, tetracaine is three times more neurotoxic. This incident triggered a class action lawsuit in 2021. The court verdict showed that 83 victims suffered skin necrosis and the total compensation reached 4.7 million yuan. The key lies in the order of ingredients-according to the “Technical Specifications for Safety of Cosmetics”, ingredients with a concentration of more than 1% must be arranged in descending order. If water is ranked after benzyl alcohol, there is definitely something fishy.
Don’t be fooled by “natural extracts”. A Japanese product claims to contain 98% Centella asiatica extract. In actual testing, it was found that the active ingredient hydroxymadecassoside only accounted for 0.3%, and the rest was all water and thickeners. For a truly effective anesthetic cream, the active ingredient must account for at least 30%. For example, the standard formula of compound lidocaine cream is 2.5% lidocaine + 2.5% prilocaine. If it is 0.5% less, the effect will be halved. A laboratory has conducted a comparative experiment: when the lidocaine concentration dropped from 4% to 3%, the anesthetic onset time was extended from 20 minutes to 47 minutes, and the pain blocking rate also dropped from 92% to 61%.
Recently, it is popular to play the “compound formula” trap. A new product claims to add menthol to enhance the effect. In fact, menthol will constrict blood vessels and reduce the penetration rate of anesthetics. Clinical trials show that the analgesic effect of a formula containing 1% menthol is 40% lower than that of pure lidocaine preparations. What’s more pitfall is that some products mix hormones. In the case of illegal addition investigated in Jiangsu last year, a “strong anesthetic cream” contained 0.05% dexamethasone, causing 23 users to develop hormone-dependent dermatitis, and the average treatment cycle was as long as 8 months.
Confirm the applicable population
This matter is more fatal than choosing a product. Last year, Peking Union Medical College Hospital received 11 cases of children’s anesthetic cream poisoning, all of which were parents who used adult products on children under 5 years old. The “Medical Device Classification Catalog” clearly states: Products containing more than 2.5% lidocaine are strictly prohibited for children under 6 years old. A 2-year-old boy developed respiratory depression after using a certain online celebrity cream. The blood drug concentration test showed that the amount of lidocaine absorbed exceeded the standard by 7 times, and he went directly to the ICU for three days.
Pregnant women are even more at risk. In 2023, the Food and Drug Administration reported that a certain brand did not mark pregnancy contraindications, resulting in abnormal uterine contractions in 23 women in early pregnancy after use, of which 4 cases caused miscarriage. In fact, lidocaine is classified as Class B in the FDA pregnancy drug classification, but prilocaine in compound preparations can penetrate the placental barrier, and the concentration of prilocaine in umbilical cord blood can reach 60% of the mother’s body – this matter has long been reported in the journal “Obstetrics and Gynecology Anesthesiology”: the use of compound anesthetic cream in the late pregnancy increases the incidence of fetal bradycardia to 9.7%, which is three times that of the general population.
Diabetic patients should not take it lightly. According to statistics from the Shanghai Ninth Hospital last year, 28% of diabetics who used anesthetic cream on their feet had skin damage and infection, and the average healing period was extended to 21 days. The key is that peripheral nerve lesions lead to dull pain perception – an uncle mistakenly used 45℃ hot water to soak his feet after applying anesthetic cream, and the scald area reached 8cm² before he discovered it. If the scope of application on the medical device registration certificate says “intact skin use”, do not apply it to the ulcer wound, the penetration rate will increase by 300% and cause poisoning.
Do you think the elderly can use it casually? The Guangzhou Center for Disease Control and Prevention found that the incidence of dizziness after using anesthetic cream for people over 70 years old was as high as 19%, which is 4.2 times that of young people. The core problem is the liver’s metabolic capacity-the half-life of lidocaine clearance in 65-year-old patients was extended from 1.8 hours to 4.5 hours, and the probability of blood drug concentration peak exceeding the standard soared to 37%. There is a ruthless trick: look at the “pharmacokinetic parameters” in the instructions. If it says “metabolized by CYP3A4 enzyme”, those with liver dysfunction will pass directly.
Sensitive skin has to screen ingredients desperately. In 2021, South Korea’s Medyto compensated 214 consumers for a total of 3.8 billion won for not marking the benzyl alcohol allergy warning. Domestic sampling data show that the incidence of irritation reactions of anesthetic creams containing propylene glycol in eczema patients is as high as 44%. A girl did not do a patch test before doing semi-permanent makeup, and her whole face was red and swollen-later tests found that she was allergic to polysorbate 80, and the amount of this emulsifier added to the anesthetic cream usually reached 1.2%-3%.
Tattoo artists, please take note: the “black technology anesthesia patch” that sold well at a certain tattoo exhibition has the scope of application written as “trunk and limbs”, but the actual registration information limits it to “single use area ≤ 10cm²”. Last year, a customer in Hangzhou used an area of 200cm² on his back, resulting in lidocaine systemic absorption and poisoning. During rescue, the peak blood drug concentration reached 6μg/mL (the safety threshold is 5μg/mL). The “maximum dosage” on the medical device registration certificate is accurate to milligrams, such as “no more than 4mg per kilogram of body weight”. An excess of 50% may cause epilepsy.
Test effect feedback
Don’t believe the merchant’s “90% user feedback is painless”. Last year, the Zhejiang Consumer Protection Committee tested 20 anesthetic creams, and the actual median pain blocking rate was only 67%, and the worst was only 41% – a tattoo shop owner applied it 45 minutes in advance according to the instructions, but the customer still cursed in pain. Later, the pain tester was used to measure that the nerve conduction velocity was only reduced by 28%, far below the industry standard of 60%. Want to know the real effect? I’ll teach you a wild way: apply it on the back of the hand, poke it with a toothpick at a force of 2N. If you don’t dodge within 10 seconds, you will be qualified. This method is three times more accurate than the “subjective feeling score” given by the merchant.
Time difference can also expose the trick. A certain online celebrity cream claims that “it takes effect in 30 minutes and lasts for 4 hours”. Actual clinical monitoring shows that the standard deviation of the onset time is as high as ±18 minutes, and the duration is reduced to 127 minutes. There is a cruel case: a beauty salon used a certain anesthetic cream for ultrasonic knife, but the customer jumped up in pain in the middle of the process. Later it was found that the peak anesthetic intensity of the product appeared 53 minutes after application, which was nearly twice as late as the marked 30 minutes. The “pharmacodynamic parameters” on the medical device registration certificate hide the truth, such as “Tmax (peak time) ≤ 40 minutes” is a hard indicator.
Don’t be fooled by “numbness”. Peking Union Medical College conducted a control experiment: two groups of subjects used real anesthetic cream and placebo respectively, and 67% of them could not accurately distinguish them – because Vaseline plus menthol can also create false numbness. If you really want to see the data, you have to use a laser Doppler blood flowmeter to measure local blood flow. The vasoconstriction rate of regular products should reach 35%-50%, while the actual measurement of a certain micro-business product is only 7%, which cannot block the conduction of pain nerves at all.
Monitoring of emergencies is more important. Last year, a lady in Guangzhou prepared her own anesthetic cream before getting a water light injection. As a result, she had tachycardia and was sent to the emergency room. A blood test found that the lidocaine concentration soared to 5.2μg/mL (safety threshold 5μg/mL). Afterwards, it was found that she also used a heating mask, which caused the skin temperature to rise by 2.3℃ and the drug absorption rate to increase by 40%. So now experts carry an infrared temperature gun with them – stop using it immediately if the skin temperature exceeds 36.5℃. This trick can reduce the risk of poisoning by 87%.
Teach you to use a mobile phone to measure the time effect in seconds: download the decibel test APP, scream at the same volume before and after application, and the sound pressure level drops by less than 10dB, indicating that the anesthesia has failed. A review blogger used this method to expose a “cinema-level” product. The results showed that the pain-related screams were only reduced by 3.7dB after use, while the same product in a regular hospital could achieve a difference of 21dB. A more professional approach is to measure the change in skin resistance. After normal anesthesia, the stratum corneum resistance will drop from 50kΩ to 15kΩ. Products with an impedance drop of less than 60% will be returned directly.
Batch differences are even more deadly. In 2023, the Food and Drug Administration found that the fluctuation coefficient of anesthesia intensity of different batches of a certain brand reached 0.38 (the industry standard should be ≤0.15). If you buy a bad batch, the effect will be directly reduced by 40%. There is a real tragedy: a beauty salon bought three boxes of the same product in a row, and the customer complaint rate soared from 5% to 34%. Later, it was discovered that the manufacturer changed the emulsifier supplier, causing the lidocaine release rate to drop from 0.8mg/cm²/h to 0.3mg/cm²/h.
Check for side effects
This is something you really can’t take lightly. According to data from the National Center for Adverse Drug Reaction Monitoring last year, contact dermatitis caused by anesthetic creams accounted for 37% of all beauty complaints throughout the year, of which 63% of cases were caused by incorrect prediction of skin reactions. There is a typical case: a girl did not do a test behind the ear before using the online celebrity anesthetic cream, and her face swelled up like a pig’s head. The emergency room measured the IgE antibody concentration to 250kU/L (normal value <100kU/L), and she was directly hospitalized for five days-in fact, the instructions had already written “patch test required 48 hours before use”, but 99% of people didn’t even read it.
Don’t think the tingling sensation is normal. A 2023 study in the Journal of Clinical Dermatology found that the probability of anesthetic creams containing benzyl alcohol causing a burning sensation was 29%, 3.2 times that of other formulas. Even more insidious is a certain micro-business product that added 1.2% of polyethylene glycol 400, resulting in osmotic overload, and the peak blood drug concentration of the user exceeded the standard by 53%, directly causing bradycardia. I’ll teach you a wild trick: Scan with an infrared thermal imager after application, and wash it off immediately if the temperature rises by more than 0.5℃ – this trick can reduce the risk of poisoning by systemic absorption by 78%.
Time management is fatal. The medical device registration certificate clearly states that “single use should not exceed 60 minutes”, but a beauty salon asked customers to apply it for 120 minutes to save costs, and 17 people had metallic taste hallucinations. Blood drug concentration monitoring shows that the concentration of lidocaine metabolite MEGX after overtime use is 2.4 times the safe value. There is a counterintuitive data: for every 0.1mm increase in skin thickness, the incidence of toxic reactions of anesthetic cream increases by 12% – so the use of heels must be reduced by 40% compared to the face. This matter was particularly emphasized in the 2022 FDA warning letter.
Cross-reaction is even more fatal. A girl in Hangzhou applied anesthetic cream and then sprayed alcohol for disinfection, which resulted in chemical burns. The Food and Drug Administration found in a flight inspection that the pH value of products containing propylene glycol plummeted from 5.8 to 3.2 after contact with ethanol, and the corrosiveness increased 10 times. Real experts know to look at the “Incompatibility Taboos” column – the instructions for a certain medical device clearly state “Avoid using with products containing cationic surfactants”, and this life-saving tip is regarded as nonsense by 90% of people.
Long-term use is a big mine. The Korean KFDA tracked people who used anesthetic cream for more than 3 months and found that 28% had local neuropathy, and the electromyography showed that the sensory nerve conduction velocity decreased by 19%. The worst is a live broadcast celebrity who used anesthetic cream every day to cover the pain of microneedles. After half a year, the tactile threshold increased to 3 times the normal value, and he didn’t even feel the scald of boiling water. The medical device management regulations have long stipulated “no more than 2 times a week”, but the merchants will never tell you actively.
Systemic toxicity is hard to prevent. In 2021, a hospital in Nanjing admitted a patient with lidocaine poisoning, with a blood drug concentration of 9μg/mL (safety value <5μg/mL), which is on the edge of the lethal dose. Tracing back found that the area of his back used reached 10% of his body surface, far exceeding the 5% upper limit of the medical device number. Now the first aid guide requires: immediately measure the electrocardiogram if perioral numbness occurs, and intravenous fat emulsion must be injected if the QRS wave width exceeds 110ms – this trick can reduce the mortality rate from 37% to 6%.
Select formal channels
This matter is very deep. Last year, the Food and Drug Administration and Pinduoduo conducted a spot check on medical beauty anesthetic creams and found that the counterfeit rate of unauthorized stores was as high as 71%. There was a hot link with monthly sales of 5,000+, but the actual delivery was a copycat product with a cosmetics production license number – a low-quality cream with a cost of 8 yuan per tube, and it dared to sell for 198 yuan with a fake anti-counterfeiting code. Here’s a trick: log on to the official website of the Food and Drug Administration to check the registration of medical device numbers, and find the list of officially authorized e-commerce platforms marked in the “After-sales Service Agency” column. Currently, only 23 platforms in the country have obtained the qualification for online sales of Class II medical devices, and even a certain Dong self-operated is not on the list.
Don’t be fooled by the “same style as the hospital” rhetoric. In the counterfeiting case uncovered in Hangzhou in 2023, the criminal gang recycled the discarded packaging boxes of the tertiary hospitals, refurbished them and filled them with industrial-grade lidocaine, with a profit margin of an astonishing 890%. The truly reliable channel depends on the accompanying order – regular medical products must be accompanied by cold chain transportation temperature control records when they are delivered. For example, anesthetic cream stored at 2-8℃ must have temperature sensor data in the logistics track, and will be directly rejected if the fluctuation exceeds ±3℃.
Cross-border shopping is even more of a minefield. Among the smuggled anesthetic creams from South Korea intercepted by Shenzhen Customs last year, 93% of the Chinese labels were added later, and the actual ingredients were 40% higher than the registered concentration. For legally imported medical device products, the outer packaging must be laser engraved with “Guo Xie Zhu Jin” + registration number, such as “Guo Xie Zhu Jin 20231234”, and the customs clearance batch can be checked in real time in the “Imported Medical Device Database” of the State Food and Drug Administration. A purchasing agent boasted that it was “exclusively for theaters” but actually did not even have a customs declaration form. It was fined 500,000 yuan after being reported by a professional counterfeiter.
Don’t be too naive about offline channels. At a beauty exhibition in Shanghai, 37% of the exhibitors provided medical device certificates that were PS. One booth displayed a “production license” numbered XK2020-001, which actually corresponds to the cotton swab production qualification. People in the industry know that they must log in to the National Enterprise Credit Information Publicity System on site to check whether the “production scope” on the production license includes “Class II 14-08 anesthesia equipment”. This code can be fatal if one digit is wrong.
Price fluctuations hide tricks. The terminal retail price of regular anesthetic cream is subject to the “Medical Device Price Management Measures”, and the gross profit margin shall not exceed 35%. A micro-business claimed that “factory direct supply 50% off”, but it turned out that it was a second-hand dealer who was selling goods, and the batch number did not match the registration information of the Food and Drug Administration. Remember: medical device products must issue special value-added tax invoices, and the medical device registration certificate number must be indicated on the invoice. 90% of the channels that dare not even issue general invoices have problems.
Hospital pharmacies are more tricky. In 2022, a private hospital in Jiangsu was exposed to selling anesthetic cream with a purchase price of 38 yuan to patients for 480 yuan. Later it was discovered that it was a three-no product that was whitewashed by relying on the qualifications of a public hospital. The legal process is: the hospital must retain a copy of the supplier’s “Medical Device Business License”, and the business scope clearly includes anesthesia equipment. This detail can filter out 83% of illegal channels.