Yes, it is. People have gotten better after having been told by someone in a labcoat that what they're taking is a placebo.

if you referring to Kaptchuk TJ, Friedlander E, Kelley JM, et al. 2010, that study still involved some deception[1]. See also Locher C, Frey Nascimento A, Kirsch I, et al. 2017

[1]: https://sciencebasedmedicine.org/placebo-effects-without-dec...

Placebo is by definition highly subjective, and not even in the sense of one's opinion, but rather that it works or not at a subject level.

Do you assume that, or did you read about it in studies?

I read about it in studies!

see, for example:

Hohenschurz-Schmidt D, Phalip J, Chan J, et al. 2024 Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials.

“The average short-term placebo effect was small,”

Strijkers RHW, Schreijenberg M, Gerger H, Koes BW, Chiarotto A. 2021 Effectiveness of placebo interventions for patients with nonspecific low back pain: a systematic review and meta-analysis

“probably not clinically relevant.”