Azelaprag dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
The mid-stage study of azelaprag with tirzepatide, in 204 adults with obesity, was stopped. The registry says why: liver enzymes rose in some people taking azelaprag. No azelaprag study has been registered since.
Evidence grade for Azelaprag: Preliminary. The rule: studied in people, but no published study has had people take it. The sum on this page: 2 registered with no result. A grade counts how much has been done to people, not whether it works.
- People given it
- 0
- Human studies
- 0
- Found nothing
- 0
Dose
No human dose established
No published study on this page has given this compound to people and reported a result.
2 registered with no result
No first-hand reports gathered yet. That is a gap in what we have collected, not a finding that nothing has been reported.
Goal pages: Fat loss and metabolism
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Azelaprag is a test pill that switches on the apelin receptor, a signal muscle sends when you exercise. The idea was to protect muscle while people lose weight on drugs like tirzepatide. Its main study was stopped because of a liver problem. It is not approved.
What people take it for
- Keeping muscle while losing weight on a GLP-1 drug.
- An exercise signal in a pill.
What studies in people showed
The main study had 204 adults with obesity, aged 55 and over. They took the pill with tirzepatide, or tirzepatide alone. It was stopped because liver enzymes rose in some people on the pill. They had no symptoms that mattered. No results on weight or muscle were ever posted. A smaller study of 16 healthy older people finished but has published nothing. The muscle benefit is only shown in mice.
What people report
Reports, not study results
The good
- We have not collected user reports on this one yet.
The bad
- Liver enzymes rose in some people in the main study, which is why it was stopped.
Where these come from: The bad line is from the study registry on this page. We have not collected user reports on this one yet.
My bottom line
The idea was smart, and the study stopped on a liver warning. You cannot feel liver enzymes rise. If you are on a GLP-1 drug, protect your muscle with lifting and protein, and check your blood work.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Azelaprag has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Losing weightno headcount stated · 1 study
35 of the 36 indexed goals have no study of any kind behind Azelaprag
No study in people, animals or cells on this page reports a result for these. That does not prove Azelaprag does nothing for them. It does mean anything you have heard about Azelaprag and one of these did not come from a study cited here.
Show full evidence
What is Azelaprag?
The mid-stage study of azelaprag with tirzepatide, in 204 adults with obesity, was stopped. The registry says why: liver enzymes rose in some people taking azelaprag. No azelaprag study has been registered since.
Azelaprag is a pill from BioAge Labs. It switches on the apelin receptor, called APJ. The science case came from a 2018 paper in Nature Medicine. It showed that apelin, a peptide released by working muscle, falls with age, and that restoring apelin signals reversed muscle decline with age. Every treatment in that paper was in mice. The human part only measured people's apelin.
BioAge took a pill version into people. The biggest study, called STRIDES (NCT06515418), put 204 adults with obesity, aged 55 and over, on azelaprag once or twice a day on top of weekly tirzepatide, or on tirzepatide alone. The main goal was percent change in body weight. The idea was that the apelin drug would protect muscle while tirzepatide, a GLP-1 and GIP drug, drove weight loss.
The study was stopped. The registry gives the reason in its own words: dosing of both study drugs was stopped after liver enzymes rose, without any symptoms that mattered medically, in some people taking azelaprag. The record shows it closed on 12 February 2025, with all participant visits done. No result on whether it worked has been published.
An earlier study of how the body handles the drug, in 16 healthy older volunteers, finished in February 2024. It has not published anything.
A 2026 paper adds a lab footnote. In tiny balls of human liver cells grown in a dish, azelaprag and tirzepatide together were more toxic than you would expect from each alone. The authors list it among real-world liver injury signals their lab model reproduced.
How does Azelaprag work?
It switches on APJ, a receptor on the cell surface whose natural keys are apelin and elabela. Working muscle releases apelin, and the level falls with age. In mice, apelin helps build new mitochondria, clear out old cell parts, and keep muscle stem cells working. Natural apelin is gone from the blood within minutes. That is why drug makers built pills like this one that last longer. Whether switching on APJ protects muscle in a person on a GLP-1 drug is the question the stopped study was built to answer. It did not answer it.
What have studies in people found about Azelaprag?
There are two registered human studies: a mid-stage study of 204 people that was stopped, and an early study of 16 people on how the body handles the drug. Neither has published a result, and the bigger one stopped because of a liver warning sign.
- NCT06515418 (STRIDES): 204 adults with obesity aged 55 and over. Azelaprag once or twice a day plus weekly tirzepatide, against tirzepatide alone. Main goal: percent change in body weight. Stopped.
- The registry says it was stopped because liver enzymes rose, without any symptoms that mattered medically, in some people taking azelaprag. Dosing of both drugs was halted.
- No lean mass, weight or physical function result from that study has been published or posted.
- NCT06141889: an early study in 16 healthy older volunteers, measuring only how the body handles the drug. Finished February 2024. No results posted.
What this does not tell you: Because the study was stopped and nothing has been posted, there is no published evidence on whether azelaprag does what it was built to do. Raised liver enzymes without symptoms is a blood test finding, not a set of liver failure cases. The registry does not say how many people were affected or how high the enzymes went. A liver signal that stops a 204-person study usually ends a drug program. But the actual numbers are not public.
The state of the research
This is the cleanest recent example of why the biology of exercise signals, called exerkines, has not produced a drug. The mouse result was strong and made sense. The drug was a pill, the company was well funded, and the study design was smart. Pair it with tirzepatide, where losing muscle during fast weight loss is a real problem, and measure whether the apelin drug protects muscle. It got to 204 people and then stopped on a liver safety signal. The liver is where small-molecule drugs most often fail.
One correction is worth recording, because the study is often cited wrong. The study with tirzepatide is STRIDES, NCT06515418. There is no registered azelaprag study named BICEP.
None of this settles the apelin system itself. Dripping apelin into people has real, repeatable effects on blood flow and blood pressure. And the idea that it protects ageing muscle has never been tested to a real health outcome in a person. What is settled is that this pill, at these doses, with tirzepatide, caused enough of a liver signal to stop the study.
The evidence, in charts
Fig. 1a · how many people
2studies in people cited, but none says how many people took part
number of people not stated
We do not draw a total, because none of the studies in people on this page gives one. Read the sources below for what each study measured.
We read the number of people from the source lines on this page. Where a line gives no number, we count nothing for it. We do not guess.
Fig. 1b · evidence mix
2 of 4 sources here are studies in people. The rest are not.
- Study in people · done in people250%
- Animal study · done in animals125%
- Lab (cells in a dish) · cells or tissue125%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 4 different years, 2018 to 2026, counted from the list of sources on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Small molecule
- Molecule weight
- Not on file
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: Not disclosed. The company's pharmacokinetic study in older adults completed but has not been published.
No amino acid sequence is on file for Azelaprag, which is expected: a small molecule is not built from amino acids.
The studies we cite
- Study in people2025Efficacy and Safety of Oral Azelaprag Plus Once Weekly Tirzepatide Compared with Tirzepatide Alone in Participants with Obesity Aged 55 Years and Over
The trial was stopped because the drug was inflaming livers. 204 people with obesity aged 55 and over were enrolled to test azelaprag added to tirzepatide against tirzepatide alone. Dosing of both drugs was halted when liver enzyme rises turned up in some people taking azelaprag. Nobody had symptoms from it. The trial is recorded as terminated and closed in February 2025. No results at all have been posted, so there is nothing here about whether the drug worked.
Phase 2, 204 participants actual, started 27 June 2024, completed 12 February 2025, status TERMINATED. Primary outcomes were mean percent change in body weight for the once-daily and twice-daily azelaprag arms. The registry's stated reason for stopping, verbatim: dosing of both study drugs was discontinued due to observation of liver transaminitis without clinically significant symptoms in some subjects receiving azelaprag. No efficacy results have been posted.
- Study in people2024Pharmacokinetics Study of Azelaprag (BGE-105) in Older Adult Healthy Volunteers
This trial finished and has published nothing. 16 healthy older adults took azelaprag so researchers could measure how the body handles it. It ran from November 2023 to February 2024 and the registry records it as completed. No results have been posted there and no paper has appeared. That is the whole entry. Nothing published is not the same as nothing found, and either way there is nothing to read.
Phase 1, 16 older adult healthy volunteers, single and multiple dose pharmacokinetics, started 17 November 2023 and completed 2 February 2024. COMPLETED with no results posted and no publication located.
- Animal study2018The exerkine apelin reverses age-associated sarcopenia
The mouse paper the drug was built on. Apelin falls with age in people and rodents, and in older people it tracked with the benefit of exercise. That part only measured people. Every treatment, including restoring apelin to improve muscle, was in mice.
The paper the programme was built on. Apelin production falls with age in humans and rodents and correlates with exercise benefit in older people, which is the observational human half. Every intervention, the knockouts and the restoration of apelin signalling that improved muscle function, was in mice. PubMed's metadata labels this record a phase 3 randomised trial because of the embedded human cohort; it is not an apelin administration trial.
- Lab (cells in a dish)2026Mechanistically resolved prediction of compound hepatotoxicity using primary human liver spheroids-Application to recent real-world cases
In a dish, using tiny balls of human liver cells. The model reproduced several recent real-world liver injury warnings, including extra toxicity when azelaprag and tirzepatide were combined. It was published after the study stopped, so it explains the result. It did not predict it.
Three-dimensional primary human liver spheroids reproduced several recent clinical hepatotoxicity signals, explicitly including synergistic toxicity on azelaprag and tirzepatide coexposure. In vitro, and published after the trial stopped, so it explains rather than predicts.
Common questions
Has Azelaprag been tested in people?
Not in a completed trial cited here. 2 registered with no result. The mid-stage study of azelaprag with tirzepatide, in 204 adults with obesity, was stopped. The registry says why: liver enzymes rose in some people taking azelaprag. No azelaprag study has been registered since.
What is the Azelaprag dosage?
No human dose established. No published study on this page has given this compound to people and reported a result. 2 registered with no result
Is Azelaprag FDA-approved?
Not approved. Investigational only. The mid-stage study that combined it with tirzepatide was stopped because of raised liver enzymes, a sign of liver damage. No further azelaprag trial is registered.
Did the azelaprag phase 2 work?
Nobody knows, because it did not finish. It was stopped because liver enzymes rose, and no result on whether it worked has been posted or published. Treat any claim about its weight or muscle results as unsupported.
Why was the trial stopped?
The ClinicalTrials.gov record says dosing of both study drugs was stopped after liver enzymes rose, without any symptoms that mattered medically, in some people taking azelaprag. Separately, a 2026 study in lab-grown balls of human liver cells found azelaprag and tirzepatide were more toxic together.
Can I buy azelaprag?
It is an unapproved test drug, and its only mid-stage study stopped on a liver safety signal. Anything sold under that name is not the study product under study supervision. And the one known risk of this drug is one you cannot feel.
Is azelaprag the same as apelin?
No. Apelin is the body's own peptide key for the APJ receptor, and it is gone from the blood within minutes. Azelaprag is a pill built to hit the same receptor long enough to work as a drug.
Does this mean apelin does not preserve muscle?
It means the idea has still never been fully tested in people. The muscle evidence for apelin is a mouse paper from 2018, with a group of people whose levels were only measured. The one study built to test it in people stopped early for an unrelated safety reason.