Vitamins and supplements. Fitness apps. Home health care services for the elderly. Concierge medical groups.

These products and services might not appear to have very much in common, but they all sit on the peripheries or edges of the traditional health care system.

And Silicon Valley's entrepreneurs and venture firms can't get enough of them.

Founders often talk about about how challenging it can be to break into the multi-trillion dollar medical sector. Health care startups face regulatory hurdles, long sales cycles and a high burden of proof — and that means it can take more than a decade to make a return.

As a result, many venture-backed entrepreneurs are looking instead at opportunities on the fringes of the health care system, such as cash-only health services that don't require insurance or tests and apps that aren't regulated by the U.S. Food and Drug Administration.

For tech investors, these opportunities hold the chance of an outsized return in five years or less. That often valuations on par with consumer Internet start-ups.

"Less regulation means faster time to market, more flexible marketing options, and a broader customer base," said Jon Sakoda, general partner at New Enterprise Associates.

Sakoda's firm has made several bets in the non or less-regulated health sector including Ritual, maker of vitamins by subscription, and Pager, an app for people to schedule a doctor's visit to their home. (NEA also invests in more traditional health start-ups through its biopharma fund).