Lipstick is an essential cosmetic for many girls, but there are always rumors circulating about its potential health risks, such as lead poisoning and cancer.

So, what's the truth about lipstick?

More than 90% of lipstick raw materials can be divided into dyes, spices, wax (to maintain the shape of the lipstick), and oil. Lipstick may also contain heavy metals such as lead, preservatives, coloring agents, stabilizers, and antioxidants like butyl hydroxyanisole (BHA) and butyl benzyl phthalate (to enhance lipstick gloss).

Given the diverse ingredients in lipstick, one might wonder if consuming it could be toxic. Synthetic waxes, often used in lipstick production, contain chemicals harmful to the human body.

Dyes and fragrances are mainly derived from coal tar, some of which are carcinogenic. However, the concern most commonly cited against lipstick is its potential lead and mercury content.

It's essential to understand that there are stringent standards for producing lipsticks that come into direct contact with the human body. According to the Hygienic Standard for Cosmetics, the upper limit of lead content in lipstick is 10 mg/kg.

Usually, a person would need to ingest more than 2 grams of lipstick at once to be poisoned, which is equivalent to consuming 75 kg of lipstick in one go.

With advancements in production technology, the heavy metal content of cosmetics continues to decrease. If production adheres to these standards, ingesting raw lipstick would not expose one to significant risk.

A Canadian study suggests that women consume an average of 4 pounds (about 1.8 kilograms) of lipstick in their lifetime, roughly equivalent to 300.

So, what about lead poisoning? A blood lead level of ≥2.9umol/L (600ug/L) is one of the indicators for diagnosing mild lead poisoning. Considering an average blood volume of 4,500ml in a normal adult, mild lead poisoning would amount to 2.7mg of lead in the blood.

A standard-quality lipstick (approximately 5g) contains 0.0005mg of lead. Thus, even if all the lipstick applied to the lips were absorbed into the bloodstream, one would need to consume 5,400 pounds (about 1.8 kilograms) of lipstick, or about 300 tubes, to develop mild lead poisoning.

In simpler terms, one would have to consume 5,400 lipsticks before experiencing mild lead poisoning. Since one lipstick typically lasts two months, it would take 900 years of continuous consumption of lipstick to reach toxic levels.

Therefore, while eating lipstick won't lead to poisoning, it's worth noting that lipstick can attract bacteria, dust, and other harmful substances from the air due to its strong adsorption properties.

Now, what about the shelf life of lipstick? Despite being small, lipstick is remarkably durable, often lasting beyond a year. However, it's essential to be aware of its shelf life to avoid potential harm.

Generally, an everyday lipstick has a shelf life of three years. The packaging of lipstick indicates its shelf life upon opening, usually represented as 24m or 36m, indicating 24 or 36 months from the moment the lid is opened.

To prevent expired lipstick and any associated health risks, it's advisable to use lipstick within one year of opening it.