The one with the issue.
Often, the person who needs the remedy the most ends up advocating it the most vocally. The person is likely to go through the trouble to look through all the possible remedies, dive deeper into each, and is most likely to empathize with others struggling with similar pains.
This presents a great lesson and a reminder to cultivate a growth mindset.
Don’t be discouraged if you find yourself with a severe weakness. As long as you are aware and continue to work to improve, you may be the best suited person to come up with the best remedy for the weakness. Because you understand how painful it is, you can build a passion strong enough to come up with the solution to the problem.
A lot of experts and successful people got to where they are by solving their own problems.