Creatine: The Supplement You Are Probably Ignoring (and Shouldn't Be)

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Let me guess. You are trying to lose weight, you are eating less than you used to, and somewhere around 2pm every day, you feel like you have been hit by a slow-moving truck. Your workouts feel harder than they should. You are losing weight, which is great, but you are not sure if what you are losing is actually fat or if your body is quietly cannibalizing the muscle you spent years building.

This is where creatine comes in. Creatine is one of the most studied supplements in existence. It is not a steroid. It is not a stimulant. It is not some shady powder sold at a gas station. It is a compound your body already makes, found naturally in meat and fish, and it plays a fundamental role in how your muscles produce energy. Think of it as a rapid-refill system for your body's energy currency, a molecule called ATP. When you run out of ATP during a hard effort, creatine is what helps you recharge it fast enough to keep going.

Honestly, I think most active adults should be taking creatine. Full stop. The research is that consistent. But if you are on a GLP-1 medication like Wegovy, Zepbound, or Foundayo, creatine moves from "should probably consider" to "really should be doing this."

Here is the part nobody tells you when you are thrilled about the number dropping on the scale. When you lose weight, especially quickly and especially with reduced appetite from GLP-1 medications, your body does not just lose fat. It also loses muscle. And losing muscle is a problem, because muscle is metabolically expensive to maintain. The more muscle you have, the more calories your body burns at rest. Lose the muscle, slow the metabolism, make long-term weight maintenance harder. That is the cycle we are trying to break.

Creatine helps interrupt that cycle in a few different ways. First, it fuels your workouts better. When your calories are lower than usual, your energy during exercise drops. Creatine supplementation maintains your ability to generate power during short, intense efforts, which means your resistance training sessions stay productive even when you are running on less fuel. A 2024 meta-analysis in the Journal of Strength and Conditioning Research reviewed 12 randomized controlled trials and found that people doing resistance training who supplemented with creatine gained an average of 1.14 kg more lean body mass and lost 0.7 kg more fat mass compared to people doing resistance training with a placebo. Same workout. Different outcome.

Second, creatine may directly help preserve muscle tissue during a calorie deficit. Research on adults over 50, a population that faces accelerated muscle loss during weight loss, showed that creatine combined with resistance training produced greater reductions in body fat percentage and better preservation of lean muscle mass compared to exercise alone. The mechanism is not fully nailed down, but the data is consistent.

Third, and this one gets less press, creatine may help reduce the mental fatigue that comes with calorie restriction. Early research suggests it has a role in brain energy metabolism, and anyone who has ever dieted aggressively knows that the brain fog is just as real as the physical exhaustion.

GLP-1 medications are remarkable at one thing: quieting the constant background noise of hunger. If you are on one, you know the feeling. Food just stops taking up so much mental real estate, and you eat significantly less without much effort. That is the point.

The problem is that when your appetite is suppressed that dramatically, the quality and completeness of what you do eat becomes critically important. A study presented at the European Congress on Obesity found that GLP-1 users were eating only about 54 grams of protein per day on average. That is roughly half of what they actually need. When you are not eating enough protein and you are losing weight rapidly, your body will take muscle to make up the difference. That is not a theoretical risk. It is happening to a lot of people on these medications right now.

Creatine does not replace protein. You still need to hit your protein targets. What creatine does is give your muscles a better fighting chance in the environment GLP-1s create: lower total food intake, potentially lower protein intake, and the physiological stress of significant calorie restriction. It is an inexpensive insurance policy for the muscle you are working hard to keep.

Full transparency: when you first start creatine, the scale may go up a little. This is water. Creatine pulls water into your muscle cells as part of how it works. This is not fat, it is not bad, and it resolves. Do not let it rattle you. The number on the scale is not the whole story, and if you are already on a GLP-1, you know the weight will continue to move in the right direction.

Older recommendations suggested a "loading dose" of creatine when you start. The old protocol was a loading phase of 20 grams a day for five days to saturate your muscles quickly, followed by a maintenance dose. The newer evidence suggests you can skip the loading phase entirely and just start with 3 to 5 grams per day. You will reach the same saturation level in about three to four weeks. The loading phase mostly matters if you need results faster for a specific event. For most people, the slow ramp is fine and easier on the stomach.

Creatine monohydrate is the form with the most research behind it. It is also the cheapest. Do not get distracted by fancier versions with fancier price tags. Plain creatine monohydrate, third-party tested, is what you want. My favorite is Thorne creatine because it mixes well in my morning Earl Grey tea, and I don't notice any gritty texture.

Click here to check out their website.

Honestly, most active adults should be on creatine. Specifically: anyone actively trying to lose weight while maintaining muscle, especially if you are doing resistance training. Anyone on a GLP-1 medication where appetite suppression is reducing overall food and protein intake. Women in perimenopause and menopause, where muscle loss is already accelerated by declining estrogen. Active adults over 40 who want to preserve their athleticism and functional strength as they age. And anyone whose workouts have started to feel harder than they should without a clear reason.

One quick side note: creatine is generally very safe, but if you have kidney disease or are at risk for kidney problems, have a conversation with your doctor before starting. We'll deep dive into the lab changes you can sometimes see in a future blog.

Creatine is not glamorous. It does not have a celebrity spokesperson or a pastel-colored box with before and after photos. What it has is decades of solid research showing it helps you hold onto muscle when your body is under the stress of weight loss, exercise, calorie restriction, or aging. It is cheap. It is safe. It works best when paired with resistance training and adequate protein.

Creatine is the recommendation I make to almost every patient I see. If you are on a GLP-1, it is not optional in my mind. It is part of the protocol. Take your protein, lift your weights, and throw in your 5 grams of creatine. Your future self will thank you.

TL;DR on the Study

Study 1: Desai et al., 2024. Journal of Strength and Conditioning Research. https://doi.org/10.1519/JSC.0000000000004862

The basics: Creatine supplementation combined with resistance training improves body composition in healthy adults under 50.

Who was in the study: 266 adults under age 50 across 12 randomized controlled trials reviewed in a systematic meta-analysis.

What they did: Compared resistance training plus creatine supplementation against resistance training plus placebo, measuring changes in lean body mass, fat mass, and body fat percentage.

The results: Creatine users gained an average of 1.14 kg more lean body mass, lost 0.7 kg more fat mass, and reduced body fat percentage by 0.9% more than the placebo group. Results held regardless of training experience or volume. Adding carbohydrates to creatine did not improve outcomes.

Why it matters: If you are lifting and taking creatine, you are getting measurably more lean mass and less fat than if you are just lifting alone. Not dramatically more, but consistently more. That adds up over time.

The catch: This is a meta-analysis, meaning it pools together different studies with different populations and protocols. Individual results vary. Also, all participants were doing structured resistance training, so the benefits are specific to people who are actually lifting.

How it works (probably): Creatine increases phosphocreatine stores in muscle, which allows faster regeneration of ATP during high-intensity effort. This lets you train harder, recover better, and provide a stronger stimulus for muscle retention and growth. Separately, creatine may have direct anabolic effects on muscle protein metabolism independent of training.

Study 2: Forbes SC et al., 2023. Nutrients. https://pmc.ncbi.nlm.nih.gov/articles/PMC10609732/

The basics: Creatine plus resistance exercise produces a small but real reduction in body fat percentage in adults under 50.

Who was in the study: 266 participants across 12 studies, adults under 50, generally healthy.

What they did: Systematic review and meta-analysis comparing resistance exercise plus creatine to resistance exercise plus placebo, focused specifically on fat mass outcomes.

The results: Creatine plus resistance training produced a statistically significant reduction in both body fat percentage and absolute fat mass compared to exercise alone, though the effect size was described as "very small."

Why it matters: Creatine is not a fat burner, and this confirms that. The effect on fat is real but modest. The real value is in muscle preservation, not fat loss. Managing expectations here is important.

The catch: Small effect size means you should not be taking creatine hoping for dramatic fat loss. The muscle retention benefit is the main event. Fat reduction is a side effect of having more muscle and better workouts.

How it works (probably): More muscle mass burns more calories at rest. Better workouts during a calorie deficit mean more fat burned during training. Creatine supports both of those indirectly.