Measured as a percentage the answer is yes, and measured in kilograms it is not, which is the single most useful fact on this page. A meta-analysis pooling five phase 3 tirzepatide trials found 18.16% weight loss in Asian populations against 17.92% in predominantly non-Asian ones, at a p value of 0.94 [1]. The same participants measured in kilograms lost 16.72 kg against 23.46 kg, at a p value of 0.03, and the explanation is that the non-Asian trial populations started heavier. Only 148 Asian participants received tirzepatide across the two trials supplying them, and the authors state that an underpowered comparison of that size cannot confirm equivalence.
Trials of these drugs report percentage weight loss, which is convenient and quietly consequential, and the disagreement between the two units is the reason this question is harder than it looks. The pooled figures across the whole literature are in the weight-loss averages, where a single mean of 9.36% sits on top of trials that almost entirely disagree with each other.
Why the two units disagree
Measured as a percentage, the Asian and non-Asian trial populations lost essentially the same amount: 18.16% against 17.92%, with a p value of 0.94. Measured in kilograms they did not: 16.72 kg against 23.46 kg, with a p value of 0.03. Both statements describe the same participants in the same trials.
The authors are unusually careful about what their own null means. Only 148 Asian participants received tirzepatide, across two trials, and they state plainly that the comparison is underpowered and cannot confirm equivalence. A p value of 0.94 on a sample that small is absence of evidence rather than evidence of sameness — the distinction that governs the frailty analysis, where the sample was large enough for a null to mean something.
The design carries a further limit. This compares across trials rather than within one, so the Asian and non-Asian groups differ in every way two separate trials differ — sites, era, baseline characteristics, background care — and ethnicity is only one of them. Heterogeneity on the headline effect was also substantial, at I² = 77%.
The trial that was actually run in East Asia
The strongest evidence about this population is not a subgroup at all but a randomized trial conducted in it. Two hundred and one East Asian adults with overweight or obesity were randomized to oral semaglutide at 50 mg daily or to placebo, and mean weight change came out at 14.3% against 1.3% [2]. Some 84.3% of the treated group reached a 5% reduction against 17.2% on placebo, gastrointestinal adverse events affected 63.4% of them, and 4.5% stopped because of an adverse event. What that trial cannot settle is whether a tablet a reader can buy resembles the one it used, which is the problem set out in the oral versus injectable comparison.
Mean starting weight in that trial was 91.9 kg, against roughly 113 kg in the large Western obesity trials, so a percentage taken off it is not the same quantity of body mass at all. That single line explains the kilogram gap in the tirzepatide pooling without invoking ethnicity, drug response or metabolism, and the fuller reading of the dose and its conditions sits in the 50 mg trial.
What the Japanese data adds, and what it cannot
Two Japanese records extend the picture in different directions. In a subgroup of 116 Japanese participants from the ESSENCE liver trial, steatohepatitis resolved without worsening fibrosis in 63.1% against 36.8%, a difference of 26.65 percentage points with a 95% confidence interval from 7.43 to 45.86 [3]. The fibrosis endpoint in the same subgroup gave 7.07 points with an interval running from −11.48 to 25.62, which crosses zero and therefore answers nothing, and the reading of that pair is in the Japanese ESSENCE subgroup.
The second record is national rather than clinical. Japan publishes dispensing quantities for every strength of tirzepatide, and strengths of 7.5 mg and above rose from 13.0% of the mix to 24.0% between June 2024 and March 2025 [4]. That is a description of a market rather than of patients, because a market where new people keep starting low and one where existing people keep climbing produce the same aggregate shift, and the dispensing file says so itself.
What a reader should take from it
The transferable lesson is about units rather than ethnicity, because any comparison between populations with different baseline weights will look different depending on whether it is reported as a percentage or an absolute. Trials almost always choose the percentage. The same trap sits behind cross-trial comparisons like the ecnoglutide trial, where entry criteria set a lighter starting population, and behind the subgroup ranges in the sleep apnea subgroups.
None of this supports a claim that these drugs work differently by ethnicity, and none of it supports the opposite claim either. What exists is one underpowered indirect comparison, one randomized tablet trial in 201 people, one liver subgroup of 116, and a national dispensing file that counts kit units rather than patients. That is a thin evidence base for a question this frequently asked, and saying so is more useful than picking whichever number reads better.