The studies of propranolol before speeches, exams and surgery point in different directions. A resident surgeon trial reported significant effects on judged anxiety and tremor. A public speaking pilot reported that propranolol did not reliably outperform placebo. A speakers' study reported both lower rated anxiety and impaired recall of difficult items in anxious subjects.
Speakers, anxiety ratings and memory
A 1983 study of speakers' performance and memory compared propranolol 40 mg with a matched placebo tablet in anxious and non-anxious human volunteers. The abstract does not state the number of participants. It reports that propranolol clearly reduced rated anxiety in the non-verbal behaviour of anxious subjects, as well as the anxiety observed in the speech of the anxious compared to the non-anxious. It also reports that propranolol impaired recall of difficult items in the memory of anxious subjects.
Resident surgeons
A 1998 randomized, double-masked, crossover study had 5 third-year ophthalmology residents take a capsule containing either propranolol, 40 mg, or placebo 1 hour prior to performing ophthalmic microsurgery. As judged by the resident surgeon, the abstract reports a highly significant effect of propranolol in decreasing anxiety (P = .0058), reducing surgical tremor overall (P < .0001), and reducing tremor while placing the first 3 sutures following lens extraction (P < .0001).
The same abstract states that it is unknown whether decreased tremor and anxiety improved surgical outcome. It also states that there were no side effects reported or observed in any of the surgeons. With 5 participants and a 40 mg capsule, this does not show how often side effects occur in other people or at other doses.
Exams
A 1991 study of high school students was an observational comparison, not a placebo-controlled trial. Thirty-two high school students who had already taken the SAT and who had stress-induced cognitive dysfunction on exams were given 40 mg of propranolol one hour before they retook those tests. Mean SAT scores with beta-blockade were 130 points higher than on the initial SAT done before entering the study without medication (p = less than .01). The comparison was with an earlier test taken without medication, and the abstract describes no placebo group.
A 1985 double-blind cross-over study of acute propranolol in medical students taking examinations did not state the dose in its abstract. The abstract reports that treatment with propranolol was associated with an improvement in total score of 9.2 +/- 3.9 marks (P less than 0.05), an improvement in mental arithmetic score of 5.6 +/- 2.3 marks (P less than 0.05) and an improvement in verbal reasoning score of 3.6 +/- 2.4 marks (NS). NS means the verbal reasoning result was not significant.
A public speaking pilot and mixed prior findings
In a 2020 pilot study of propranolol for fear of public speaking, participants underwent a stress-inducing speech task composed of 3-min preparation and from 0 to 9 min of public speaking, in 1-min increments. They then received either 40 mg of propranolol (n = 40) or placebo (n = 20), double-blind, allocated 4:2 for each speech duration.
The abstract reports that self-reported speech distress and questionnaire measures of public speaking anxiety both showed clear reductions following treatment. However, propranolol did not reliably outperform placebo, regardless of speech duration at treatment. The PubMed record includes a conflict of interest statement saying a person named in it is the co-founder of Kindt Clinics, a private clinic that provides reconsolidation-based treatments. The study's title refers to a reconsolidation-based treatment.
A 2021 abstract of a laboratory stress study states that prior findings are surprisingly mixed about whether beta-blockade (e.g., propranolol) blunts subjective stress, with many studies reporting no effects.
What this does not tell you
These studies differ in task, dose and measure, and some abstracts leave out key details. The speakers' study does not state the number of participants, and the medical students study does not state the dose. The surgeon ratings were the resident surgeon's own judgments, from 5 residents. The SAT comparison had no placebo group, so it cannot show that propranolol caused the difference in scores. The public speaking pilot reported clear reductions in two measures but no reliable advantage of propranolol over placebo.
The speakers', exam and surgeon studies were published between 1983 and 1998. None of these abstracts says whether any person should take propranolol, at what dose, or what it would do in that person's circumstances. A licensed provider decides that.