Growing up in a small Missouri town without any sisters, Casey Lewis felt alienated from other women. "Teen magazines were my gateway into women's health and the world," she says. Her experience became the launch point for Clover Letter, an email newsletter and community for teenage girls. Her readers, Lewis explains, probably don't visit traditional outlets like The New York Times or CNN, but they have a desire to stay informed on the most pressing current events. In 2015, Lewis and her co-founder, Liza Darwin, quit their media jobs to start Clover Letter, which now counts more than 50,000 readers. Based in New York City, Clover Letter generates revenue mostly by charging its clients, which include Penguin and Dove, a fee to run branded content. Still, one major challenge has been convincing investors that Generation Z does, in fact, spend time on email--as opposed to Snapchat, which now has more than 150 million daily active users. "Every investor we've met with said we needed to get on Snapchat Discover," says Lewis. "But we said we're going to try this other thing." Clover Letter recently closed a seed funding round of $300,000. The founders, both 29, say the U.S. presidential election--as well as the new administration--has given them a renewed sense of purpose for their readers. "As we're watching the government implode," says Darwin, "these girls still find optimism." --Zoë Henry

In Uganda alone, nearly 600,000 newborns require medical intervention for complications at birth. That's a problem that Teresa Cauvel and Sona Shah are on a mission to solve. Founded in 2015, their health tech startup, Neopenda, makes wearables that monitor four newborn vitals: heart rate, respiration, blood oxygen saturation, and temperature. Each battery-charged sensor is integrated into a baby hat and wirelessly transmits data to a central monitor. "A lot of my inspiration comes from the nurses and clinicians who tirelessly care for hundreds of newborns every week," says Shah. Given that many hospitals in the developing world are understaffed, Neopenda offers the solution of time and cost-efficiency. A typical--and more advanced--monitor in the U.S. costs $2,500, but Shah and Cauvel aim to reduce Neopenda's price to $75 per unit. The team plans to begin test trials in Uganda this year. Should Neopenda receive approval from the Uganda government, it can expand across East Africa. "The progress we've made and support we've received in less than two years has been exciting," says Cauvel, who notes that Neopenda's board consists of a diverse crowd of experts, from a clinical professor of pediatrics at U.C. San Diego to the SVP of external affairs at the TB Alliance. "It's our sole mission to give millions of newborns the healthy start to life they deserve." --Vanna Le

Every college student knows that the first day moving into the dorm is exciting, but kind of a pain in the neck. The sheets don't fit. The concept of a shower caddy is completely new. And suddenly, a laundry hamper seems like a necessity. Unlike most college students, cousins Shanil Wazirali and Sagar Hemani think they've got a fix. Their company, Roomify, consolidates student shopping needs in one big box of stuff, all color-coordinated, all delivered to their dorm. Its best-selling box is the $299 "Doin' It Big," which includes 42 items ranging from bedding to a bulletin board. The five-person company designs and manufactures everything itself, which allows it to keep prices low. Starting out, the founders had a leg up: Their fathers ran a family business that sourced white-label hardware and school supplies. "They guided us and told us which factories to work with," says Wazirali. "We were able to find out exactly where companies like Target were manufacturing." In March, Roomify closed on $1.1 million in financing. "Every year we sell out," says Wazirali. "And every year we're like, man, we're on to something." --Kimberly Weisul

A few days before Halloween on 2012, armed with less than $1,000 and a site built using a free website builder, Alexandra Cristin White, then 23 years old, officially launched her online business, Glam Seamless. White's company sells tape-in natural hair extensions for women. Sales have grown from $55,000 in 2014 to over $2.5 million two years later. "I think the reason why the company has been so successful is because I never focused on the numbers," White says. "I never focused on 'Oh, I need to hit this goal.' I mean, numbers are important, for sure, but I think what is more important is surveying your customers and really listening to what they want." Another factor that helped? She didn't need to pay office space. White and her team worked remotely on the business during the first three years of the company. They would meet on coffee shops or co-working spaces when needed. Now Glam Seamless has its offices and a "hair room" in Hoboken, New Jersey. White explains that she chose to enter the tape-in extensions market because it wasn’t as saturated as the clip-on alternative. A few lessons on SEO and a YouTube channel later, Glam Seamless became one of the top players in the space. "In the day of internet and e-commerce, anything is really possible," says White, now 28. "You don't need an investor to start, you don't need a big office, you don't need anything. You just need the grit, the determination and passion for whatever you're doing."

Businesses are increasingly recognizing that charitable giving and volunteer opportunities are an important way to attract and engage employees. But few resources exist to easily organize and track those activities in one place. Envested, a New York City-based startup, wants to change that. The software company makes it easy for employees to get involved in charity projects and launch their own, as well as reducing the time businesses need to spend on attendant administrative tasks. Isa Watson, a former chemist at Pfizer and executive at JPMorganChase--and an accomplished classical pianist on the side--founded Envested in 2015. The five-person company began generating revenue through software subscriptions at the end of last year, and projects revenue to rise to more than $700,000 in 2017. It has raised $760,000 in funding from investors including Newark Venture Partners, which also recently accepted the startup into its accelerator program. Envested currently has about 100 local nonprofit groups on its roster. So far, its software is proving to be a hit: An average of 50-65 percent of customers' employees use it, four to six times the adoption rate for products from Envested's competitors. --Doug Cantor