The blaze started inside Integral Yoga Natural Vitamins, a street-level shop in an apartment building at 234 W. 13th St., and prompted firefighters to evacuate people from units directly above about 5 a.m., according to witnesses and the FDNY.
"It was pretty bad. You could see the smoke coming out. It was a lighter color," said Ed Ambrose, 45, who was delivering food at the time to Integral Yoga's grocery store across from the vitamin shop.
"They had at least six or seven engines out here on the block. They had the ladders up and firefighters were on them with the hoses out. The firefighters were helping people out of the building," he added.
Firefighters brought the flames under control about 5:30 a.m. and no injuries were reported, the FDNY said.
Fire marshals were still investigating the cause of the fire, the FDNY said.
The shop is a wing of the Integral Yoga Institute on the same block, which has offered yoga classes since its founding in 1972, according to its website.
The institute later opened a grocery store and then the vitamin shop, which sells health products including vitamins, herbs, flower essences, oils, teas, tinctures and more.
"It's awful," said Dan Rivera, 29, a manager at the grocery.
"This has been here for more than a decade. It's a big shock. I don't know what we do going forward," he added.