How long does it take to see results from working out?

It depends on which result you mean, and they arrive at different speeds. The first thing to change is performance. In a classic training study by Moritani and deVries, adaptation in the nervous system accounted for most of the strength increase during the first weeks: you lift more because the brain gets better at recruiting the muscle, not because the muscle has already grown. So feeling stronger and steadier within two to three weeks is exactly what to expect.

Visible muscle takes longer, and here the body fools the eye at first. When Damas and colleagues followed untrained people through a training programme and measured inside the muscle, what looked like growth in the first week turned out to be largely swelling and repair after exercise-induced damage, not new muscle tissue. Only around week ten did the increase correspond to genuine myofibrillar growth. Their review of muscle protein synthesis reaches the same conclusion: the acute spikes right after a session say little about how much you will actually grow.

In short: strength and stamina show up within a few weeks, clearly visible muscle usually after two to three months of regular training, and the pace varies with how untrained you were to start, how you eat and how you sleep. Someone completely new sees the most in the first months. The more trained you become, the slower it goes.

Impatience meets a market built for it. "30-day" videos and before-and-after photos sell programmes, supplements and apps, and a fast transformation is a better advert than an honest "come back in three months". The images are also often shaped by lighting, a pump, dehydration and posing rather than by weeks of progress. On top of that we measure the wrong thing: we look for change in the mirror every day, where it shows up least, instead of in the weights and reps, where it shows up first. When the mirror doesn't answer right away, it reads as the training not working, even though the body has already begun adapting on the inside.

Don't judge the training by the mirror in the first weeks. What moves first is performance, so keep a log of weights, reps and how the sessions feel. If they slowly climb, the training is working, well before anything shows on the outside. Give visible muscle two to three months of regular training before you draw conclusions, and hold on in the meantime. The progress is real long before it is photogenic.