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Half of finished skin trials never post results

In our snapshot 2,557 skin studies have completed and 1,074 have posted results. The missing half is not random — disappointing findings vanish more often.

By Patrick and Michelle7 min read
Article in one pictureMore than half report nothing
  1. 1,074 of 2,557The rest finished and stayed silent
  2. Silence is not randomDisappointing findings vanish more often
  3. Ask for the denominatorThree positive studies out of how many?
Of 2,557 completed skin studies, 1,074 have posted what they found.
On this pageThe size of the silence5

Quick answer

The bottom line

Of 2,557 completed skin studies in our snapshot, 1,074 have posted results — meaning more than half of finished research is invisible. That matters because unreported studies are more likely to have found nothing, so the published picture of any treatment is systematically rosier than reality. When you read that a treatment is backed by several positive studies, the honest follow-up is how many studies were run in total. Our condition pages show both numbers, and the gap between them is often the most useful thing on the page.

At a glance

Three things worth remembering

  1. 2,557 skin studies in our snapshot have completed. 1,074 have posted results, so more than half report nothing publicly.[1][3]
  2. The silence is not random: studies that found little are less likely to be written up, so the visible evidence runs optimistic.[4]
  3. Melasma is the extreme case at 6.8 percent of completed studies reporting, against 47 percent for psoriasis.[1]

Section 01

The size of the silence

Our snapshot covers 3,745 unique interventional studies across acne, eczema, psoriasis, rosacea and melasma. Of those, 2,557 have completed, and 1,074 have posted results. That leaves roughly 1,480 finished studies whose findings are not in the registry, involving tens of thousands of people who gave their time on the understanding that it would add to what is known.[1][3]

The rate varies sharply by condition. Rosacea reports at 49 percent, psoriasis at 47, acne at 43.1, eczema at 34.7, and melasma at 6.8. The conditions with commercial sponsors report far more often, partly because those sponsors are the ones legally required to.[1][2]

Section 02

Why the missing half is not a random half

If unreported studies were a random sample, the published picture would be incomplete but unbiased. They are not. Research on this pattern consistently finds that studies with disappointing or null findings take longer to be written up and more often are never written up at all — by researchers with nothing exciting to report and by sponsors with nothing to gain.[4]

The effect compounds. A review that pools the published studies inherits their optimism, guidance built on those reviews inherits it again, and by the time a claim reaches a product page it has been through three layers that each quietly favoured the positive. This is why treatments sometimes underperform in practice compared with their reputation.[4][3]

Section 03

What the rules actually require

  • Many registered studies must post summary results within a year of completion, and the requirement applies regardless of what was found.[2]
  • Coverage is not universal: early-phase studies, some device studies and studies outside the relevant jurisdictions fall outside it.[2][5]
  • Studies completed before the rules took effect were never obliged to report, and much older dermatology research sits in that group.[2][3]
  • Enforcement has historically been light, so compliance depends substantially on whether a sponsor chooses to comply.[2][4]

Section 04

How to use this when weighing a treatment

Ask for the denominator. "Three studies support this" is a different statement depending on whether three studies were run or thirty. Our per-condition pages carry both counts, so the ratio is visible rather than something you have to infer.[1][3]

Weight treatments where the reporting rate is high. A field reporting at 47 percent still hides a lot, but its published record is far more trustworthy than one reporting at 6.8 percent, where a handful of small positive studies may be all that ever surfaced from a much larger effort.[1][4]

Be most sceptical where a treatment is old, cheap and unsponsored. Those studies are the least likely to have been written up, so both the good and bad news about them is thin.[4][2]

Section 05

The part that is improving

Registration itself was the hard-won change. Before it, a study could be run and buried with no public trace that it had ever existed, and there was no way to count what was missing. Now the gap is at least measurable, which is what makes an article like this possible.[2][5]

Reporting rates have risen over time and continue to. The practical habit for a reader is simple: when a claim rests on studies, check whether the studies are findable, and treat unfindable ones as weakly as you would treat no study at all.[2][4]

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