I know that in nutritional health, Licorice root is often used to help replenish depleted adrenal glands along with adaptogenic herbs. Adrenal glands are how the body stores reserve energy. If you experience prolonged stress over many months or years the adrenals can become worn out beyond repair. Some people think that adrenal fatigue, if it goes unhealed, passes the point of no return and becomes Chronic Fatigue, meaning you can no longer produce any reserve energy in the body. Again, it’s just a theory, although a long standing one. But as for licorice (in diluted tea form without any additives or sugar in it ) it is said to slowly repair the adrenals AND is anti-viral AND helps with digestion, all of which could help us. But yes dosage matters - just because it’s natural doesn’t mean it’s harmless, take all things in moderation and consult a doctor.
A small warning not to get your hopes up: Licorice is good for a lot of things but it’s a slow healer, like you might feel stronger over the course of a year, maybe two so it’s still helpful but I don’t think you will suddenly feel fantastic within a week. I’d say its more of a help than a cure.