I personally find this study totally ethical, but I guess the counter-argument would be “How risky is an experiment allowed to be before it’s considered unethic

I personally find this study totally ethical, but I guess the counter-argument would be “How risky is an experiment allowed to be before it’s considered unethical, even if people are volunteering?”. Like let’s say we wanted to verify if some liquid was a poison, and we thought it had a 50/50 chance of killing someone, and we offer someone £500k to drink it, is that ethical? Probably not. I mean ethics are always subjective, but I don’t think that’s right. Does it make it ethical if it will probably save two lives? Uhh, I’m still uncomfortable with it... So after that point you are just arguing about how risky the experiment is allowed to be before it becomes unethical, and what benefit it will have for other people in relation to that risk. Again, I agree with you and the trial because the risk seems low enough and the reward seems high enough - this is just the counter argument.