The guide

What happens, week by week

By GyroscopeUpdated November 14, 202612 sources

Week one is mostly water on the scale. Your muscles are full by about day 6 if you load, or about day 28 on 3 to 5 g a day. The extra rep on hard sets shows up once they’re full, and any new muscle comes over the next months of training.

Most people judge creatine in the first week, because that’s when they’re paying the most attention. It’s the worst week to judge it. The scale has jumped, your stores are only partly full, and anything you feel in the gym is as likely to be a good night’s sleep or the hope of a new supplement.

Creatine works on a calendar. Stores fill first, then the extra reps start to count, then the training does the rest. If you know which week you’re in, nothing along the way is a surprise.

It’s like planting a vegetable garden

You water the bed on day one and the soil is heavier straight away. Nothing has grown. The plants come up over weeks, and only if you keep tending them. Creatine water is the wet soil. The muscle is the plants, and the tending is your training.

Days 1 to 7: the stores fill, the scale rises

If you load, your muscles go from their normal level to full in about six days. In the 1996 trial that set the timeline, 20 g a day raised muscle creatine by about 20% in six days. A 2021 review found that a loading week typically adds 1 to 3 kg (2 to 7 lb) on the scale, mostly water.

The two trials that weighed people at the end of a loading week found less than that. In 2003, 32 lifters on 25 g a day were 0.75 kg (1.7 lb) heavier at day 7, though their body water had risen 1.37 L. In 2016, 13 soccer players loading at 0.3 g per kg gained 1.0 kg (2.2 lb) and 2.3 L of body water against placebo.

If you take 3 to 5 g a day, the same rise is spread over four weeks. On the curve we draw between the measured days, you’re a little over halfway full by the end of week one.

Most people won’t feel anything this week. A few might. In a 2004 study of 11 men who loaded for 5 days, the 3 who took up the most creatine lifted more on the leg press at the end of the week. They were the ones who started with the lowest stores.

Weeks 2 to 4: full, or getting there

If you loaded, you’re full and the scale has levelled off, usually by the end of the first week. From here, a daily 3 to 5 g keeps you there.

On 3 to 5 g a day, you’re about 80% of the way to full by day 14 on our curve, and full by day 28. The scale drifts up slowly with it, if it moves at all. Plenty of people on the slow path never see a creatine week on the scale.

This is when the first effect you can use arrives. With your stores full, each hard set has more phosphocreatine behind it. In lifting trials, reps at the same weight rose 26% with creatine against 12% without it, which on a set of 10 is about one or two more reps.

Weeks 4 to 12: the extra reps add up

This is where creatine earns its keep, and only if you’re training. Across 22 studies of creatine with weight training, strength rose 20% on creatine against 12% on placebo. Across 35 trials, lean mass rose 2.4 lb (1.1 kg) more with creatine and lifting than with lifting alone, and didn’t move without exercise.

A 2025 trial is the best case against getting excited here. Researchers gave 63 adults, 34 of them women, 5 g a day or nothing. After a 7-day start, the creatine group had 1.1 lb (0.51 kg) more lean mass on a body scan. Then both groups lifted for 12 weeks and both gained about 4.4 lb (2 kg) of lean mass, with no extra gain on creatine. The researchers think the scan counted creatine’s water as lean mass in that first week, and that more than 5 g a day might be needed to add muscle on top of training.

That trial was one of many, and the pooled results still show a gain with lifting. But it’s a fair warning that the effect is small enough for a single trial of 63 people to miss.

Months 3 to 24: the long game

The longer trials are mostly in older adults. Across 22 trials of people in their late 50s to 70 who lifted two or three days a week for 7 to 52 weeks, creatine added about 3 lb (1.37 kg) more lean tissue. In a two-year trial of 237 women around 59 who lifted three days a week and walked six, the women on creatine walked 80 m in 47.1 seconds by the end, against 48.6 at the start, while the placebo group barely changed. A 2026 pooling of seven trials in women after menopause found 16.5 lb (7.5 kg) more on the leg press.

What doesn’t happen, at any week

• Fat gain. Trials from one week to two years haven’t found creatine adds fat. The weight you see early is water.
• A mood change you’d notice. Across 11 trials, creatine moved depression scores by 2.2 points, below the 3 points people notice, and the evidence was rated very low.
• Anything on day one. Your stores need days to weeks to fill, so anything you feel on day one comes from something else.

Week by week, in one table

What happens when you stop?

Your stores drift back down. In the 1996 trial, muscle creatine was back to where it started 30 days after the men stopped. The International Society of Sports Nutrition puts it at 4 to 6 weeks, and no study has found stores falling below where they began. The water leaves with the creatine, so the scale comes back down too.

How do you know it worked?

Not from the scale, which goes up for everyone, and not from how you feel. Test one benchmark, such as push-ups or a dead hang, twice before you start, and again at week eight. How to tell if it worked has the method, and the prove-it tool sets your retest date.