One good study is a start.

A cell experiment, an animal study and a human trial each answer a different question. Here's how to tell them apart.

Where the study happened

Lab work can show a pathway or a reaction. Animal studies show what happens in a whole body. Neither shows that a treatment helps people.

Human studies vary too. A case report describes one person. An uncontrolled study follows a group with nothing to compare against. A randomized trial uses chance to decide who gets what, which makes a well-run trial easier to trust.

Look past the headline

Who was in it? Check the condition, the ages and how people were picked.
What was it compared with? A placebo, another drug and nothing at all give different answers.
What did they measure? A blood marker, a symptom score and hospital visits are different results.
How long did it run? Short studies can miss late side effects or a benefit that fades.
How sure is the result? Small samples, missing data and wide ranges all weaken it.

Know what kind of source it is

A trial registration may describe a planned, running, completed or stopped study, with or without posted results. Registration alone does not establish participant exposure or efficacy. A preprint may not be peer reviewed yet. A company press release can pick its best numbers. A published paper has more detail, but publishing doesn't fix a weak design.

Compare like with like

Two trials can look comparable and still differ in patients, length or methods. A head-to-head trial is a better place to start when comparing two treatments. Check its design too.