Were Black and Latina women included in GLP-1 weight-loss trials?
Key takeaways
Dr. Linda's take
The question underneath this one is usually quieter and more personal: was this even tested on someone like me? It is a fair thing to ask, and it deserves a straight answer rather than reassurance.
Here is the honest version. Yes, Black and Latina women were part of the big weight-loss trials. And no, they were not always represented in proportion to how common obesity is in their communities. Both of those things are true at once, and holding them together is what lets you trust the evidence without being naive about its limits. Where researchers have gone back and looked closely at how these medications performed across racial and ethnic groups, the results have been reassuring. But representation in the enrollment numbers is a separate, real issue, and it is worth naming out loud. Everything below is what the trial data actually shows.
Were Black and Latina women actually enrolled in these trials?
Yes. The large weight-loss trials did include Black and Latina participants, and the published demographics let you see the exact proportions.
In the STEP 1 and STEP 3 semaglutide trials, participants who reported race were White (75.3%), Black (8.8%), Asian (10.6%), or another racial group (5.3%), and 13.9% reported Hispanic or Latino ethnicity. The picture shifted in the trial that enrolled people with type 2 diabetes: in STEP 2, 8.9% of participants were Black and 27.3% were Asian.
For context on the size of these studies, here is what the numbers showed. In the STEP 1 trial, which enrolled 1,961 adults with overweight or obesity, those who took semaglutide 2.4 mg lost about 14.9% of their body weight over 68 weeks, compared with about 2.4% on placebo. In the SURMOUNT-1 trial, adults with obesity who took the highest dose of tirzepatide lost about 20.9% of their body weight over 72 weeks, compared with about 3.1% on placebo. These were the trials that changed how obesity is treated, and Black and Latina women were among the people in them.
Did these medications work as well across race and ethnicity?
This is the part I most want women to hear, because it is where researchers did the careful work.
In a post hoc analysis of three STEP trials, there were no significant interactions between the treatment effect of semaglutide 2.4 mg and race or ethnicity. In plain language, the analysis did not find that the medication worked meaningfully differently from one racial or ethnic group to another. The weight-loss effect of semaglutide was statistically significant versus placebo and clinically relevant across all racial and ethnic subgroups studied.
Safety was examined the same way. The safety of semaglutide 2.4 mg was consistent across racial and ethnic subgroups in that analysis. That is exactly the kind of check that answers the trust question with evidence rather than with a shrug. If you want to go deeper on this specific point, we cover whether these medications work as well for Black and Latina women in a separate piece.
So what is the honest caveat about representation?
Being included is not the same as being represented in proportion to need, and this is where the honesty has to come in.
A systematic review and meta-analysis of 27 GLP-1 obesity trials with more than 21,000 participants found that White participants made up about 79% of enrollees, while Black participants made up about 9%. That same review reported that Hispanic participants made up about 22% of enrollees across the trials. And critically, in that review, non-white individuals were significantly under-represented in these trials compared with the general population of the United States.
Why does that matter here? Because Black and Latina women carry a higher baseline risk of obesity and diabetes, so a group that shoulders more of the disease should ideally be well represented in the studies of its treatment. The reassuring subgroup findings above are real. The under-representation is also real. A thoughtful reader can hold both without letting either one cancel the other out.
What does this mean for a woman weighing her options?
This is general education, not a recommendation for any one person. But knowing how the trials were built gives you better questions to bring to a visit:
If you are trying to figure out whether treatment is even a fit for your situation, our eligibility quiz is one place to start.
Frequently asked questions
Were Black and Latina women included in GLP-1 weight-loss trials?
Yes. In the STEP 1 and STEP 3 semaglutide trials, participants who reported race were White (75.3%), Black (8.8%), Asian (10.6%), or another racial group (5.3%), and 13.9% reported Hispanic or Latino ethnicity. Black and Latina participants were part of these studies, though not always in proportion to how much these communities are affected by obesity.
Did the medications work as well for Black and Latina participants?
In a post hoc analysis of three STEP trials, there were no significant interactions between the treatment effect of semaglutide 2.4 mg and race or ethnicity. The weight-loss effect of semaglutide was statistically significant versus placebo and clinically relevant across all racial and ethnic subgroups studied.
Was safety checked across racial and ethnic groups?
Yes. The safety of semaglutide 2.4 mg was consistent across racial and ethnic subgroups in that analysis. Researchers looked specifically at whether side-effect patterns differed by group.
Were Black participants under-represented in these trials?
Often, yes, relative to disease burden. A systematic review and meta-analysis of 27 GLP-1 obesity trials with more than 21,000 participants found that White participants made up about 79% of enrollees, while Black participants made up about 9%. In that review, non-white individuals were significantly under-represented in these trials compared with the general population of the United States.
How much weight did people lose in these trials overall?
In the STEP 1 trial, which enrolled 1,961 adults with overweight or obesity, those who took semaglutide 2.4 mg lost about 14.9% of their body weight over 68 weeks, compared with about 2.4% on placebo. In the SURMOUNT-1 trial, adults with obesity who took the highest dose of tirzepatide lost about 20.9% of their body weight over 72 weeks, compared with about 3.1% on placebo.
References
1. Obesity (Silver Spring, Md.) (2024). Efficacy and safety of semaglutide 2.4 mg by race and ethnicity: A post hoc analysis of three randomized controlled trials. PubMed PMID 38932728. https://pubmed.ncbi.nlm.nih.gov/38932728/ (Accessed 2026-07-19).
2. The New England journal of medicine (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. PubMed PMID 33567185. https://pubmed.ncbi.nlm.nih.gov/33567185/ (Accessed 2026-07-19).
3. The New England journal of medicine (2022). Tirzepatide Once Weekly for the Treatment of Obesity. PubMed PMID 35658024. https://pubmed.ncbi.nlm.nih.gov/35658024/ (Accessed 2026-07-19).
4. BMJ global health (2024). Representation of racialised and ethnically diverse populations in multicentre randomised controlled trials of GLP-1 medicines for obesity: a systematic review and meta-analysis of gaps. PubMed PMID 39608857. https://pubmed.ncbi.nlm.nih.gov/39608857/ (Accessed 2026-07-19).
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*This article is general education and is not medical advice. It cannot tell you what is right for your body. Talk with a licensed clinician about your own situation.*
*Written and clinically reviewed by Dr. Linda Moleon, MD. Last reviewed 2026-07-19.*
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