The 33-year-old actress, who plays 66-year-old Rebecca Pearson on the hit NBC show, opened up in a new interview about exactly how the process works.
"It takes about three and a half hours," she told Refinery29.
So it makes sense that when the shoot ends and it's time to return to her old (er, younger) self, simple makeup remover won't cut it.
"You wrap for the day, and everyone's like, 'Bye!' But you still have an hour-long process of taking off the makeup," Moore said.
"It's a lot of chemicals," she continued. "You have to put on a greasy remover lotion in order to remove the prosthetic pieces and the ager, which goes on like a glue that you have to dry with a hair dryer. It makes the skin look crepe-y and older. Then, I have to wrap my face in hot towels, and we just keep doing that over and over again."
The process "ruins" her skin, she said. Fortunately, producers make an effort to schedule breaks between her heavy makeup days.
"They're usually pretty good about that," Moore told the website. "They'll make it so I have a day on and a day off from that makeup. It gives my skin a chance to breathe and acclimate."
Earlier this year Moore shared a behind-the-scenes glimpse of what the makeup process looks like.
"Getting older is a lot of work," she wrote on Instagram.
Now we know just how much work it really takes.
We're sure we speak for all "This Is Us" fans when we say: Mandy, we're grateful for your dedication!