How to read a peptide study | Living+ Peptides

To judge a peptide study, ask three questions. Was it done in a lab dish, in animals, or in people? Were people assigned to groups by chance? And how many people took part ^{[1, 3, 5]}? Splitting people into groups by chance lets researchers compare treatments more fairly ^[4]. Later trial phases also test a drug in more people than early ones ^[5].

Lab, animal or human?

Research on a new drug usually starts before any person takes it. FDA calls this preclinical research. Its purpose is to find out whether a drug may cause serious harm, called toxicity ^[2]. FDA lists two types, in vitro and in vivo ^[2].

In vitro means in the laboratory, outside the body ^[3].
In vivo means inside a living body ^[2].
Clinical research is medical research that studies people ^[1].

Preclinical studies are usually not very large. They must give detailed information on dosing and toxicity levels ^[2]. After preclinical testing, researchers review their findings and decide whether the drug should be tested in people ^[2]. On this site, each study row is marked as human, animal or lab, so you can tell them apart. See the research table on BPC-157 for an example ^[9].

Clinical trials vs observational studies

ClinicalTrials.gov describes 2 main types of clinical research ^[1]:

Clinical trials, also called interventional studies. Researchers assign people to get one or more interventions to test what happens ^[1].
Observational studies. Researchers collect data from people, or look at data that was already collected, but do not assign an intervention ^[1].

This matters. In an observational study, anyone using an intervention was already using it as part of regular care or daily life ^[1]. Researchers do not split the groups by chance, as they do in a randomized trial ^{[1, 4]}. Some observational studies use patient registries, which are organized collections of data that patients agree to give ^[1].

Randomized and blinded trials

In a randomized trial, people are split into groups by chance. The National Cancer Institute says using chance means the groups will be similar, so the effects can be compared more fairly ^[4].

Many trials compare a drug to a placebo. ClinicalTrials.gov defines a placebo as a substance that looks like the drug and is given the same way, but has no active drug ^[1]. In a masked or blinded trial, participants and staff may not know who got which treatment. This helps make sure the results are looked at fairly ^[1].

When you read a study, look for these words in the design: randomized, placebo-controlled, double-blind. Each one helps make the comparison fairer ^{[1, 4]}.

Sample size and trial phases

The number of people in a study matters. ClinicalTrials.gov says trials for new drugs often move in phases, each testing the drug in as few people as possible to answer its question ^[1]. FDA's drug development steps show how trials grow ^[5]:

Phase 1: 20 to 100 healthy volunteers or people with the condition. Purpose: safety and dosage. About 70% of drugs move to the next phase ^[5].
Phase 2: up to several hundred people with the condition. Purpose: efficacy and side effects. About 33% move on ^[5].
Phase 3: 300 to 3,000 volunteers with the condition. Purpose: efficacy and monitoring of adverse reactions. About 25% to 30% move on ^[5].
Phase 4: several thousand volunteers with the condition. Purpose: safety and efficacy ^[5].

A phase 1 study tells you mostly about safety and dosing, not whether a drug helps a condition ^[5].

Reading a ClinicalTrials.gov record

ClinicalTrials.gov is a database of clinical studies run by the National Library of Medicine ^[7]. Each study gets an NCT number when it is registered ^[6]. The record shows the study type, phase, enrollment and study status, and a Results tab if results are available ^[6].

Two real records show the range. The STEP 1 record for semaglutide (NCT03548935) lists an interventional, phase 3 study with an actual enrollment of 1,961 and a status of completed ^[8]. A BPC-157 record (NCT02637284) describes a phase 1 pilot study planned for 42 healthy volunteers. Its status is unknown, and it was last verified in October 2015 ^[9]. See semaglutide for how STEP 1 fits with its other trials ^[8].

Keep one limit in mind. The site says the U.S. government does not review or approve the safety and science of all listed studies. The study sponsor or investigator is responsible for the safety, science and accuracy of what it lists ^[7].

A quick checklist

Was it done in people, animals or cells ^[3]?
Was it randomized, with a control or placebo group ^[4]?
How many people took part, and what phase was it ^[5]?
Is it registered, and are results posted ^[6]?

If the answer to most of these is no, treat the finding as early. You can track the status of each peptide on the FDA Peptide Status Tracker, and learn the basics in what is a peptide ^[5].

Frequently asked questions

What is the difference between in vitro and in vivo?

In vitro means in the laboratory, outside the body. In vivo means in the body ^[3].

Why do randomized trials matter?

Splitting people into groups by chance makes the groups similar, so treatment effects can be compared more fairly ^[4].

What is a placebo?

A substance that looks like the drug and is given the same way, but has no active drug ^[1].

How many people are in a phase 3 trial?

FDA describes phase 3 trials as 300 to 3,000 volunteers who have the condition ^[5].

Does a ClinicalTrials.gov listing mean the government approved the study?

No. ClinicalTrials.gov says the U.S. government does not review or approve the safety and science of all listed studies ^[7].

Do animal studies show a peptide is safe for people?

No. Preclinical studies look for possible harm and give dosing and toxicity data before testing in people ^[2].