The world is abuzz over Merck’s new antiviral pill that promises to slash hospitalization from COVID-19 by half. The drug, molnupiravir, a hard-to-pronounce moniker named after the Norse god Thor’s hammer, Mjölnir, comes in an easy-to-swallow pill.

According to The Atlantic, to be effective the drug must be taken within the first five or so days of illness. That is a tight window of opportunity, say healthcare experts, so there is a downside to its benefits. Molnupiravir works in a similar way to the drug remdesivir, the only COVID-19 drug currently approved by the Food and Drug Administration (FDA), so it’s not a totally new formula. The advantage of the Merck drug is that it is a convenient pill that can be taken at home, while remdesivir must be given intravenously, in a hospital or clinical setting over several days, after patients are really sick.

Molnupiravir works by tripping up the virus’ ability to replicate itself, so the infection has little chance of becoming severe and causing the immune system to go haywire. According to NBC News, molnupiravir, manufactured by Merck & Co. and Ridgeback Biotherapeutics, causes the enzyme that helps replicate the virus to make so many errors that the pathogen can’t reproduce. This reduces the viral load and infection time, which prevents a dangerous immune response that could lead to serious illness and death.

In Merck’s recent clinical trial of people who had at least one risk factor for COVID-19, only 7% landed in the hospital compared to 14% in the placebo group, says The Atlantic. That is an impressive 50% reduction. So far, no serious side effects have been reported.

While monoclonal antibodies have received emergency use authorization from the FDA for early-infection cases, they also need to be infused or injected by professionals. That’s where molnupiravir, if it is authorized, would have an advantage as people could take it themselves during early stages of COVID-19 to avoid serious disease while shortening the duration of the illness, and making them less of an infectious threat to others.

In clinical trials, molnupiravir successfully reduced the levels of infectious virus quickly. On Monday, Merck applied for emergency use authorization (EUA) from the FDA for adults with mild-to-moderate COVID-19 who are at risk for severe disease or hospitalization. The FDA decision could happen in a few weeks.

For the pill to work effectively, people would have to identify their symptoms, take a COVID test, and then get a prescription from their doctor. They will also need to comply to the dosage which is four capsules twice a day for five days, a total of 40 pills, say The Atlantic.

“When we get there, that’s the idea,” said Dr. Daniel Griffin, a member of the Division of Infectious Diseases at Columbia University, according to NBC. “To have this all around the country so that people can get it the same day they get diagnosed.”

Molnupiravir isn’t cheap. A course of treatment costs $700. Merck has said that it would cut the cost of the pill in countries where vaccination rates are low and there is a desperate need for the drug.