Clinical trial payments are the money a study gives participants, usually as compensation for their time plus reimbursement for costs like travel and parking. The amount and schedule go to the IRB for review, the consent form spells them out, and FDA guidance says payment should build as the study goes on rather than depend on finishing it.
Picture a participant named Dana in a twelve-month trial. She drives 40 minutes each way to every visit, pays for parking at the hospital and takes the afternoon off work. If her payment only arrives after the last visit, she’s fronting the study’s costs for a year.
That’s the problem good clinical trial payments solve. Done well, they cover what participation costs people, respect their time and arrive while they still matter. Done poorly, they become the reason people drop out, or never sign up in the first place.
Here’s how to set them up so they’re fair to participants and easy for your team to run.
Most clinical trial participant payments fall into three buckets, and keeping them separate makes everything else easier: IRB review, budgeting and tax questions.
| Payment type | What it’s for | Typical example | How FDA guidance treats it |
|---|---|---|---|
| Reimbursement | Costs the participant pays to take part | Mileage, parking, airfare, lodging | Not seen as raising undue influence concerns |
| Compensation | Time, effort and inconvenience | A set amount per completed visit | Reviewed by the IRB as a recruitment incentive, not a benefit |
| Completion bonus | Finishing the study | A small extra amount at the final visit | Acceptable if it’s a small share and not coercive |
The distinction matters because FDA’s guidance on payment and reimbursement to research subjects treats them differently. Reimbursement for travel to and from the site, along with costs like airfare, parking and lodging, isn’t considered to raise undue influence concerns. Compensation is different: FDA says payment for participation is not a benefit to weigh against the study’s risks. It’s a recruitment incentive, and the IRB reviews it with that in mind.
So if your budget lumps everything into one “stipend” line, split it before it reaches the IRB. Each part gets reviewed on its own terms, and the split makes that review easier to follow.
Sometimes, and the randomized evidence is more nuanced than either side of the debate tends to admit.
A 2021 study in JAMA Internal Medicine tested payments inside two real clinical trials. Eligible patients were randomly offered different amounts to join, and the researchers tracked how many agreed.
In the smoking cessation trial, 21.8% of patients offered nothing agreed to join (Halpern et al., 2021), compared with 35.9% at $200 and 47.1% at $500. In the hospital walking trial, money made no significant difference: consent hovered between 43.0% and 48.1% across $0, $100 and $300.
To put the first result in practical terms, say your site needs 100 enrolled participants from a pool where about one in five says yes without payment. You’d need to approach roughly 460 people. At the rate seen with the $500 offer, you’d need about 212. That’s a lot of screening calls saved.
The study also looked for the two things critics worry about most. It found no evidence that payment made people less sensitive to research risks (undue inducement), or that it pulled in lower-income patients disproportionately (unjust inducement). Payment didn’t change how long people spent reading the risk sections of the consent form, either.
The honest catch: payment helped in one trial and not the other. It’s one lever among several, and it works best when the barrier really is cost or time rather than fear, distance or a confusing protocol.
In the US, FDA guidance sets the main expectations for how payments are structured, and the IRB approves the specifics for your study. The January 2018 guidance comes down to five points:
Taxes are the other half. Participant compensation can count as income, and your finance team decides how it’s reported. One change is worth flagging: according to IRS Publication 1099, for tax years beginning after 2025 the minimum threshold for reporting certain payments on information returns rose from $600 to $2,000, and it will be adjusted for inflation starting in 2027. Check with your tax advisor how that applies to your study, especially if some participants live outside the US.
Most of the work happens once, before the first participant walks in. Here’s the order that keeps it manageable:
A pro tip from the budgeting side: decide your rule for missed or rescheduled visits before enrollment starts. Making it up case by case is how two participants in the same study end up paid differently for the same thing.
If you also run surveys or interviews outside your trials, our guide to rewarding research and survey participants covers incentive options for lighter-touch studies.
Giftronaut handles the sending side of compensation payments, so your coordinators aren’t mailing checks or managing card stock. It’s the same setup research teams use for survey and research incentives. Here’s where it fits:
To be clear about the limits: gift cards are country-specific and can’t be redeemed in another country, even for the same brand. And a digital reward isn’t the same as cash, so confirm the format with your IRB and give participants who need it another option.
For more on sending rewards without collecting emails, see our guide to anonymous survey incentives.
Dana didn’t join the trial for the money. But if every visit costs her gas, parking and half a day’s pay, slow or confusing clinical trial payments quietly tell her the study doesn’t value her time. Pay per visit, put it all in the consent form, keep your records clean and pay within days, not months. Start with your next protocol amendment or budget review, and fix the one step that’s slowest today.
Often, yes, and your finance team decides how they’re reported. For tax years beginning after 2025, the IRS raised the minimum threshold for reporting certain payments on information returns from $600 to $2,000, so check with a tax advisor how your study’s payments are treated.
Yes, many studies use gift cards or digital rewards, as long as the IRB approves the method and it’s described in the consent form. FDA guidance asks IRBs to review the amount and schedule of all payments, so name the format up front.
Yes, for the parts they completed. FDA guidance says credit for payment should accrue as the study progresses and not depend on finishing the entire study, which is why per-visit payment schedules are common.
Yes, if it’s small. FDA accepts paying a small proportion of the total as an incentive for completing the study, as long as the bonus isn’t coercive or large enough to keep people in a study they’d otherwise leave.
Not in the randomized evidence so far. A 2021 study in JAMA Internal Medicine found no sign that payments of up to $500 made patients less sensitive to research risks or drew in lower-income patients unfairly.
Yes, with Giftronaut reward links. They don’t require recipient details at order time: you download one unique link per reward, send it through your own channel and keep the participant-to-link mapping in your own records.
Use a reward that adapts to each participant’s country. A Giftronaut Choice Card lets each participant pick a brand available in their own country and currency, and the Global Visa Reward Card covers countries without a local gift card.