The popular workout regimen Power 90 Extreme (p90x) is a video series of 12 exercise routines developed by Tony Horton that are designed to help individuals lose weight and get into shape within 90 days of starting the program. The regimen is intense and, as such, carries many risks and rewards. Consider these benefits and disadvantages before starting p90x to decide if the program is right for you.

Benefit: You Will Most Definitely Lose Weight

Unless you are a professional athlete before you start p90x, you will most certainly lose weight if you complete the program. Where average-intensity cardio routines allow you to burn 6-8 calories per minute, high-intensity workouts like p90x can help you burn up to 13 calories per minute—almost twice as much. Burning 13 calories per minute during the average 60 minute p90x workout means you’re burning 780 calories each day, enough to work off an entire meal.

Risk: The Regimen Is Dangerous for Beginners

Because the workouts in the p90x regimen are high-intensity and lengthy, they’re not really designed for people who don’t work out regularly. If you’re going from not exercising at all into p90x, there is a risk that the intensity of the workouts could cause you to suffer from health issues. Injuries like strained muscles are common among beginners, and straining a muscle will keep you from continuing your routine for a week or more while your body heals. More severe conditions can also develop, so it’s important to check with your doctor before starting p90x.

Benefit: You’ll Develop Muscles

Because p90x combines weight training, flexibility training, and cardio, it promotes weight loss, makes you more flexible, and aids muscle growth and definition. Unlike other workout programs that focus primarily on one of the three areas: weight loss through cardio, flexibility through stretching exercises, or muscle gain through weight training, p90x allows individuals to focus on all three areas in the same routine.

Risk: You Might Develop Stretch Marks

When your body changes shape due to rapid weight loss or muscle development, there is a high risk that stretch marks will form. Stretch marks form when skin tears due to rapid changes in its shape, and that tearing forms the scarring we commonly refer to as stretch marks. Stretch marks do not go away on their own, so it’s important to take preventative measures in order to prevent them from developing when starting a new workout routine. Many stretch mark prevention products can be applied to skin daily that will reduce the likelihood of stretch marks forming.

Benefit: p90x Lets You Skim the Gym

If working out at a gym is your own personal nightmare, p90x is a good way to get into shape in the comfort of your own home. Performing the routines requires little equipment—you can do some version of all of the exercises using just dumbbells and a set of resistance bands—so there’s no need to go to the gym or fill your house with workout equipment to get into shape.