The specialists, who will outline their views at next week's Charity Communications conference in London, say charities need to do more to protect the interests of beneficiaries who volunteer to speak to the media.
Winnie Coutinho, head of campaigns and communications at Changing Faces, a charity for people with facial disfigurements, said: "We are constantly asked for case studies by the media - talking about issues from a personal perspective can be very powerful and can fight stereotyping.
"The downside is that they can be very time- consuming for the person concerned, there's a danger they will be misquoted and then they might get dropped at the last minute.
"It would be useful to have some sort of formal agreement to clarify how the media outlet plans to use the case study."
Katy Weitz, director of First Features, an agency that sells real-life stories to the media, said she believed charities should ask for payment when they provide case studies.
"I don't think it would be outrageous for charities to ask for a contribution, either to the subject of the case study or to the charity that provided it," she says.
"People used as case studies often have to talk about very intimate details of their lives, and the fact is that the media has the money to pay them. People sell stories to the media all the time - it's standard practice to pay celebrities for interviews, so why shouldn't charities also receive compensation for their time?"
Weitz added that she thought most publications would respond positively to the request.
Penelope Gibbs, director of the Voluntary Action Media Unit's media-matching website Askcharity, agreed: "The money is there, whether charities ask for it or not. If payment is offered, at least half of it should be offered to the person used in the case study.
"A lot of publications already offer payment through Askcharity."
To book a place at the Charity Communications conference on 17 May, go to www.charitymedia.co.uk.