Toxic metals were found in 14 different tampon brands, according to a new study published in the scientific journal “Environment International.” Researchers found evidence of arsenic, lead, mercury, nickel and others in both organic and non-organic tampons, which the body could absorb if tampons are used during menstruation. The study did not name the tampon brands.

The findings prompted swift backlash from women online.

“So, if you don’t live under a rock, I’m sure you’ve heard the news by now,” one TikTik user said. “Tampons and the fact that there’s lead and arsenic in this. And a lot of us have known that tampons are toxic for years but to know it to this extent is actually crazy.”

But how concerned should women be if they use tampons? According to the study, all the tested tampons contained lead.

“There is no safe exposure level to lead,” the study reads. “Any proportion of lead that may leach out of a tampon and reach systemic circulation might contribute to negative health outcomes.”

The study states that lead “is associated with numerous adverse neurological, renal, cardiovascular, hematological, immunological, reproductive and developmental effects.” Even low exposure to lead “can result in neurobehavioral impacts in adults and children, including decreased cognitive function such as impaired attention, memory and learning ability.”

Non-organic tampons had higher levels of lead compared to their organic counterparts. However, organic tampons had higher levels of arsenic, which, according to the study, “is a known carcinogen and is associated with cardiovascular disease, dermatitis and other dermal effects, and respiratory and neurological disease.”

Researchers stated their study had some limitations, such as how much the body absorbed these metals. Because of these limitations, they could not estimate health risks, if any, from tampon use.

Dr. Jennifer Lincoln, an OB-GYN based in Portland, Oregon, posted a video on TikTok providing some context.

“So, should you throw out all your tampons right away because of this? If this worries you, you absolutely can,” she said. “I personally wouldn’t because these levels are very low but I hear you if you say, ‘There’s no acceptable level for lead,’ I totally get that. But I do want you to understand that we are exposed to all of these metals to some degree in our daily lives.”

Lead is present in the environment and can be found in foods, candies, spices, medicines, cosmetics and other everyday consumables.

Researchers said more testing needs to be done to determine the health risks of using tampons.