Strongest skin numbing creams typically contain 5‑10% lidocaine, with 85% of US products using it as the main ingredient. About 5‑10% of users experience skin irritation, and 2‑4% report side effects like dryness or allergic reactions. High concentrations of propylene glycol and ethanol increase the risk of adverse effects.
Common Ingredients
Skin numbing cream usually contains lidocaine in a concentration range of 2% to 10%. Strong numbing cream contains 5% to 10% lidocaine. About 85% of the numbing creams sold in the US market use lidocaine as the main ingredient. It can take effect within 15 to 30 minutes and last for 1 to 2 hours. 2%-4% of users reported similar side effects. For more details, check out which is more affordable.
The average numbing time of benzocaine is about 30 minutes, and the onset speed is between 5 to 10 minutes. Products containing benzocaine account for about 20% of the US market. About 1% to 3% of users may have an allergic reaction to benzocaine.
This can increase the permeability efficiency of active ingredients by a factor of 20% to 30%, shortening the onset time dramatically to less than 10 minutes. In some highly effective numbing cream formulations, the concentration of propylene glycol is usually controlled between 1% and 5%. About 5% of the users faced skin dryness problems when the products contained a high amount of propylene glycol.
The plant extracts added in numbing cream include aloe vera, rosemary, and green tea. The general addition ratio of the above is from 0.5% to 1%. The effective rate of the use of numbing creams containing plant ingredients is as high as above 80%.
Some numbing creams add vitamin E as an additive moisturizing ingredient. The added concentrations are generally between 0.1% and 0.5%. Products added with vitamin E sell around 15% higher than no such ingredients’ addition.
Ethanol is the common adjuvant solvent used in high-concentration numbing cream. The concentration may vary from 10% to 30%. About 10% of the people experienced mild pain in products containing ethanol.
Other popular brands incorporate borneol or menthol in numbing cream at a concentration of approximately 0.1-0.3%. Products containing menthol demonstrate up to an 87% user satisfaction rate in pain relief.
The ordinary dose of numbing cream is 30 grams to 50 grams per tube, a single use amount of about 1 gram to 3 grams. As many as 70% of users of pump-type numbing creams report a repurchase rate, which far exceeds the repurchase rate for traditional designs in a jar.
Side Effects
About 5-10% of users developed symptoms of skin irritation after the use of the numbing cream, while in about 12% of subjects, dry peeling problems could be seen after more than 7 continuous days of use of products containing lidocaine. For more information, see laser or innotox.
Serious allergic reactions upon the use of numbing cream occurred in about 2% of consumers. About 1.5% of its users developed the symptoms within 1 hour following its use.
Propylene glycol or alcohol is an ingredient added to some formulation of numbing cream. If the concentration is more than 10% it will damage the skin’s natural barrier. More than 20% products have propylene glycol over safety range. 8% of users developed mild burning or dryness after using products with high propylene glycol concentration. The dosage of applying numbing cream shall not be more than 10 grams per use.
About 15% of users also responded that the numbing effect substantially diminished after a few days of continued application. Because resistance may set in, stop the use for 1-2 days after using for 3-5 days to give the skin time to recover.
Below 30% humidity, the drying time of numbing cream is shortened by 20%-30%. About 25% of users reported reduced effects in winter.
When the blood concentration of lidocaine exceeds 5 micrograms/milliliter, mild neurological reactions may occur. Although the incidence is less than 0.5%. A comparative study of the ingredients of 30 numbing creams found that nearly 10% of products exceeded the specified concentration range. Experts recommend consumers choose certified brand products.
By covering with cling film at a temperature of 35 degrees centigrade, absorption of the cream increases by about 40%. During usage, the users must not use it for more than 30 minutes.
Skin Reactions
Mild skin reactions, including redness, occurred in 15% of the population after the use of skin numbing cream. A concentration of 5% lidocaine is considered a common specification in medical beauty and may cause 2%-3% of users to feel tingling or warmth. For more information, see Innotox safety.
Of users who continuously used numbing cream for over 5 days, approximately 18% reported skin dryness, peeling, or redness. If the propylene glycol concentration is higher than 5%, the probability of skin reactions may reach up to 25%.
Among young people aged 18-25 years, only 8% of users reported skin discomfort, while the proportion increased in the population over 50 years of age to 15%.
The incidence of allergic contact dermatitis caused by some numbing creams is about 1%-2%. For the products containing benzocaine, on average, 3 out of 1000 people reported allergic reactions like redness and swelling. These may appear within a period of 24 hours following the use of such topical anesthetic products and remain for 3 to 5 days.
When the concentration of ethanol in numbing cream exceeds 15%, it can make 10%-12% of users feel burning on their skin. This will be increased to 18% if the using environment is above 30 degrees Celsius.
When the humidity is below 30%, the skin is more prone to dryness, which enhances the irritative effects of the ingredients in numbing cream. In the winter, 25% of users using numbing cream reported significant skin dryness and itching, while this proportion drops below 10% in the humid summer.
About 0.3-0.5% of subjects developed mild contact allergies to rosemary extract. The reaction can manifest itself in the form of local redness or mild itching, which normally disappears within 48 hours after cessation. Darkening of skin color was reported in about 6% of patients after the use of numbing cream. It takes several weeks or even months for this reaction to fully recover.
Allergic Risks
About 2-4% of the users develop allergic reactions because of certain ingredients present in the numbing cream. High concentration, 5-10% of lidocaine, has a higher incidence rate in sensitive population, about 3%. These allergic reactions usually are exacerbated as redness, swelling, itching, and local skin warmth, with symptoms appearing in about 24 hours. For more details, check out Botox or fillers.
About 1.5% of the users using numbing cream containing benzocaine reported contact dermatitis (mild). The usual concentration of benzocaine is 10-20%.
Propylene glycol has an allergic reaction rate of about 0.8% to 1% while using numbing cream. Especially when the propylene glycol concentration is greater than 5%, the probability of skin redness and tingling is really increased, which is about 1.2%. Certain population parts show allergic reaction rates to rosemary or tea tree oil extracts in numbing creams of about 0.3%-0.5%.
After covering with cling film, the permeability of active ingredients may increase by 40%-50%. The incidence of allergic reactions increased from 2.5% to 4% after the use of cling film. In eczema patients treated with the EMLA patch, the allergic reaction rate is nearly 10%.
In the case of continuous use of numbing cream for over two weeks, the incidence of allergic reaction increases from 2% on the first use to 4%. So, in cases of continuous use for 3-5 days, it is best to stop the use of numbing cream for 1-2 days.
Expert Tips
5-10% lidocaine-based numbing creams are considered to be the most usable and effective products. The products with 2-4% lidocaine are good for beginners, providing a temporary skin boosters effect in as little as 30 minutes.
FDA-certified numbing cream products have a safety and user satisfaction rating that is 15% higher than other products. 0.5% propylene glycol is labeled as an auxiliary ingredient on product labels from a well-known US brand.
Application of up to 1 gram of numbing cream per square centimeter of skin achieves the best effect; more than this amount, such as over 3 grams per square centimeter, will increase the incidence rate of skin irritation by 15%-20%. Professional physicians recommend that the maximum single dose should not be more than 20 grams.
Apply in small amounts behind the ear or inside the arm and observe for 24 hours. It is possible to identify about 80% of cases in advance to prevent an allergic reaction. 0.5-1% maximum may have an allergy to either benzocaine or rosemary extract. Environmental humidity below 30% will reduce the absorption rate of numbing cream by 10-15%.
For long-term users of numbing cream, they should stop for 1-2 days every 3-5 days. About 10%-12% of users feel a large weakening of the numb effect after more than one week’s continuous use.
About 85% of the subjects agree that plant soothing ingredients can effectively reduce skin dryness and tightening caused by the numbing cream. A skin-penetration numbing cream containing 0.5% aloe vera extract reached over 70% repurchase in the market.
Covering numbing cream with cling film for 30 minutes can raise the absorption rate by 40%; in contrast, more than 60 minutes can create a burning feeling and redness on the skin for up to 15% of users. Experts suggest that the time for covering should not exceed the recommended 30 minutes.
Post-Use Sensitivity
About 12% of the users developed slight skin redness or tingling following the use of the numbing cream. This usually occurs when the products of lidocaine are more than 5%. These usually settle on their own within 24 hours.
Skin tingling, on exposure to high temperatures or cold winds, was seen in 8% users following the use of numbing cream with 10% lidocaine.
In environments with less than 30% humidity, approximately 20% of users reported skin dryness and tightness after using numbing cream. Numbing cream with 0.5% aloe vera extract can significantly reduce dryness problems, with a user satisfaction rate of up to 85%.
About 15% of users felt stronger skin reactions after continuous use for more than two weeks. Studies recommend stopping for 1-2 days after using continuously for 3-5 days.
Only 5% of young users aged 18-25 years reported mild skin sensitivity, whereas in more than 50 years of age, it was 18%. In elderly patients, low-concentration numbing creams should be used, such as 2%-4%.
Smearing a small amount of numbing cream behind the ear or on the inside of the arm and observing for 24 hours can avoid about 75% of skin discomfort reactions.
In topical anesthetic creams, alcoholic solvents such as ethanol in concentration above 10% may cause skin warmth or burning in about 10% of users. During summer, the proportion of users with heating symptoms rises to about 15%.
Clinical Studies
Researchers studied 300 participants using 5% and 10% lidocaine numbing creams. The results indicated that a 10% concentration product caused a stronger numbing effect, with an onset time of 15 minutes in comparison to a 5% concentration product, which takes 25 minutes. However, the side effect incidence rate was 12% for a 10% concentration and only 4% for a 5% concentration.
After using lidocaine numbing cream, about 9% of patients reported temporary skin dryness. Among these patients, over 70% used products with concentrations between 7%-10%. In environments with humidity below 40%, this proportion increases to 15%.
The allergic reaction rate of benzocaine is 2%, while that of lidocaine reaches 4%. The numbing time of benzocaine is about 20 minutes, slightly shorter than lidocaine.
Among young people aged 18-30 years, only 6% felt skin irritation after using numbing cream, while among participants over 50 years old, this proportion increased to 18%.
In the study enhancing the numbing effect by covering with cling film, 150 participants were divided into two groups, one covered with cling film and the other not. It was observed that the group covered with cling film had an enhanced numbing effect of 30%; however, the incidence rate of side effects increased from 5% to 11%. The study recommends that the covering time should not exceed 30 minutes.
The incidence rate of side effects of products containing aloe vera or vitamin E is less than 3%, while the average incidence rate of side effects of products without plant extracts is 7%. Among them, products containing 0.5% aloe vera extract have the highest user satisfaction of 85% in the satisfaction survey.
Continuous use of numbing cream for more than 5 days may increase skin sensitivity. 15% of users felt a weakening of the numbing effect after continuous use for a week. Experts recommend pausing for 1-2 days after continuous use for 3-5 days to help the skin recover.
In products with more than 15% ethanol concentration, about 10% of the users experienced skin burning sensation, whereas in products without ethanol, this percentage was only 3%.