You might have heard of the Stanley tumbler, the hip, trendy water bottle that has people camping outside stores or getting into fights to get their hands on one.

They’ve become a fashion accessory, especially since the company that makes the cups, Stanley 1913, has made use of influencer culture to target women and make the tumbler’s sales skyrocket. The reach of the bottles has been amplified by social media users.

But social media giveth and social media taketh away. In recent weeks, several widely shared posts on TikTok, Instagram, Reddit and X have amplified concerns Stanley cups may contain lead, with one X user calling it “The Leadening.” YouTubers have also jumped into the fray. One TikTok video on the topic was viewed nearly seven million times.

Some Stanley owners, hoping to check the claims, started to use home lead-testing kits, which experts say are not reliable. A sendup of the Stanley cup phenomenon on “Saturday Night Live” over the weekend — a sketch called “Big Dumb Cups” — even mentioned the lead in passing.

The lead discussion has popped up on Facebook comment sections, as in one group with more than 61,0000 members called “Stanley Cup Hunters + Drops” — for “passionate Stanley Cup fanatics.”

One person wrote, “If we want to dress up our lead cups with a flower straw cover and a glitter boot and show them off, lets us be!! We know they have lead, you have told us. We don’t care!”