How much strength training do you need on a GLP-1?

The 2025 joint advisory from four medical societies puts it at regular strength training at least three times a week, plus at least 150 minutes of moderate-intensity aerobic activity a week. Strength training is the half that protects muscle. The walking is worth doing, and it is doing something else.

People search for this under semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound). The body-composition answer below is the same whichever one you are on, and it is the same again if you are losing weight without any of them.

Why resistance work is not interchangeable with cardio

When you are in an energy deficit, your body has to decide which tissue to draw on. Resistance work is the signal that says the muscle is in use and should be kept. Nothing about a brisk walk sends that signal, and no amount of steps substitutes for it. This is why the advisory names strength training specifically and separately, rather than folding it into a general exercise recommendation.

Protein without the mechanical stimulus is half the equation, and the stimulus without the protein is the other half. Neither one carries the load on its own.

What the evidence looks like

The clearest trial is S-LiTE, which ran for a year in 195 adults with obesity after a diet-induced weight loss, comparing a supervised exercise programme, liraglutide, both together, and placebo. The combination reduced body fat percentage by 3.9 points, roughly double the 1.7 points from exercise alone and the 1.9 points from the medicine alone. The group doing both lost the most weight and the smallest fraction of lean mass.

That is one trial with one older GLP-1 and a supervised programme most people will not replicate exactly. It is still the shape of the thing: the exercise is not decoration on the medicine, it is what changes what the weight loss is made of.

What counts

• Anything that loads the muscle against resistance. Free weights, machines, resistance bands, or your own body weight. A press, a pull, a squat or hinge, and something for the trunk covers most of it.
• Effort that is hard near the end of a set. The last two or three repetitions should be genuinely difficult. Comfortable sets do not send the signal.
• Progression you can see in writing. The same weight for six months is maintenance at best. A record of what you lifted is also the cheapest early warning you will get about muscle, which is why it is worth keeping even on weeks you do not care about progress.
• Not steps. Steps are good for your heart, your mood and your blood sugar. They are not the muscle lever, and a step count that looks impressive can hide a training week that did nothing for lean mass.

What you can check this week

• Put two sessions in the calendar as appointments. Three is the recommendation; two that actually happen beats three that do not.
• Write down three benchmark numbers. One press, one pull, one lower body. Repeat them in three weeks and compare. This is the closest thing to a free muscle measurement that exists.
• Check what your phone is counting. Many apps log every session as generic exercise, which makes a month of walking look identical to a month of lifting. If your training is going to be readable later, it has to be recorded as resistance work.
• Eat before you train, even a little. On a suppressed appetite it is easy to arrive at a session with nothing in the tank, which turns a muscle-protecting session into a mediocre one.

Where ProForta comes in

ProForta reads exercise sessions by type, so resistance work counts toward muscle preservation and cardio and steps do not inflate the reading. It combines that with your protein, your recovery and your weight trend into one score, on a private node that belongs to you, and shows you interpreted results only. LifeCare.ID® carries the identity and the consent record.

ProForta is a wellness tool, not medical advice. Nothing here speaks to your medicine or your care. Your prescriber stays the decision-maker on both.