The Edinburgh company, which focuses on the technology and health sectors, said this will allow anyone to become an investor to its participants.
Jude Cook, chief executive, said: "For sites that do not have full FCA authorisation, the only option for ordinary people to invest is to agree to classify themselves as a professional client, which means they must waive their rights to complain to the Financial Ombudsman Service or to claim compensation under the Financial Services Compensation Scheme.
"We are very excited to be one of the few UK equity crowdfunding sites to offer true crowd investment, ensuring that we help keep the crowd in crowdfunding."
She believes the company is the first in Scotland to be regulated under FCA rules which came into effect in April this year.
ShareIn is about to launch a funding campaign for technology business Flexpansion.
That Edinburgh company helps to improve typing on a touchscreen by using adaptive predictive text software.
Earlier this year 3-D imaging firm Holoxica, also based in the Scottish capital, became the first to complete a campaign on ShareIn by raising more than £73,000.