How to Keep Your Muscle While You Lose Weight on a GLP-1

Written by Dr Jatin Joshi, co-founder and Chief Medical and Scientific Officer of Personally, and a researcher at the University of Oxford's Centre for Evidence-Based Medicine. I have a financial stake in this company, and you should weigh what follows with that in mind.

The weight is coming off. That part is working. But lately your legs feel like jelly on the stairs, your strength in the gym has quietly dropped, and somewhere a worry has taken hold that you cannot shake: what if some of what I am losing is muscle.

You are right to take that seriously, and you are not being paranoid. Rapid weight loss is rapid change of every kind, and muscle is part of what can go if you let it. The reassuring part is that losing it is not inevitable, and most of what protects it is in your hands.

The short version. When weight comes off quickly, a real share of what is lost can be lean mass rather than fat. No supplement prevents that, and anything sold as a "GLP-1 supplement" to do it is not being honest with you. What protects muscle is well established, and it goes in a fixed order: resistance training first, enough protein second, enough sleep and enough total food third. Nutrition beyond that comes fourth, and it matters least. I am going to say that plainly even though we sell the fourth thing, because if you only do one thing on this list, I would rather it was the first.

There is a reason this worry tends to arrive around the second or third month. When weight comes off quickly, your body does not only draw down fat. A meaningful share of what is lost can be lean mass, muscle included. This is not a reason to panic or to stop what is working. It is a reason to protect your muscle on purpose, which is exactly what you are trying to do. The instinct that brought you here, wanting to do this properly, is the right one.

The scale cannot tell you. It shows total weight, not what that weight is made of. The clues are in how you feel and, if you want certainty, in the data. Legs that feel like jelly on the stairs, strength slipping in the gym, a body that looks smaller but softer than you expected: these are the everyday signals people describe. A DEXA scan is how you actually see it. You do not need a scan to start protecting your muscle, but if the worry is loud, it can turn a fear into a number you can act on.

Almost everything that protects muscle comes down to four things, and they are not equally important. I am going to rank them honestly, including where we sit.

First, resistance training. This is not one of several options. It is the thing. Muscle is kept by being used, and if you give your body no reason to hold on to it while you are eating less, it will not. Twice a week is enough to change the picture. If you take nothing else from this article, take that.

Second, protein. Enough of it, spread across the day, so your body has the raw material to work with. This is the hard one on a GLP-1, and I will come to why.

Third, sleep and enough total food. Both are unglamorous and both are load-bearing. Muscle is rebuilt while you sleep, and a body running on very little energy will take what it needs from wherever it can.

Fourth, and only fourth, the nutritional bases. The vitamins and minerals the first three depend on to work properly. This is where a formula like ours fits, and it is worth being precise about what that means: it is a supporting role, and a small one. It will not build muscle for you, and it cannot compensate for skipping the first three. What it can do is make sure your body is not short of something it needs while it is doing the real work.

Anything that promises to protect your muscle without the first two is selling you something.

Here is the honest problem. The advice is "eat enough protein", but the whole point of the medication is that you do not feel like eating. On the worst days it is a few hundred calories, meat is the last thing you want, and you have tried the shakes and found most of them hard to get down. That is not a willpower problem. That is the medication doing its job.

It also means protein is the thing worth solving first, and solving it properly, whether that is with food you can face or with help from your doctor or a dietitian. What our powder covers is the fourth thing on the list: the micronutrient bases that the training and the protein depend on.

I am not going to give you a list of ingredients here, because a list is not the answer to your question. Which of these your body is actually short of, this month, at what dose, and whether any of it interacts with what else you take, is not something a list can tell you and not something you can reasonably work out on your own. That is the part worth getting right, and it is the part guesswork tends to get wrong.

One further honesty, since we are being honest. Ours is a powder you mix into a drink. For some people on a GLP-1 that is easier than swallowing a handful of capsules on a queasy stomach. For others, a drink is the last thing they want. You will know which you are, and I would rather you knew it before you ordered than after.

You have probably seen them: capsules and gummies marketed as GLP-1 boosters, or "nature's Ozempic", or a pill to cancel the side effects. Trust your instinct on those. A supplement is not a GLP-1, and anything marketed as though it were is either useless or mislabelled. Personally is not one of those products and never will be. It does not boost your medication, replace it, or treat its effects. It is nutrition that sits alongside what you are already doing, nothing more and nothing less.

The other honest thing about a GLP-1 is that you are not standing still. Your dose changes. Your appetite changes. What you can eat this month is not what you could manage last month, and your nutritional gaps move with it. A single fixed formula, bought once and never revisited, cannot keep pace with that. This is what we built Personally to do: a formula that adapts every month, to your body, your appetite, and what you are able to eat, with a note each month explaining what changed and why. And because you are almost certainly taking the medication alongside other things, Personally screens your declared medications for relevant supplement interactions and nutrient-depletion considerations before it builds your formula. Most brands never ask.

You are doing this right. You saw the risk early, you are asking the right question, and the answer is kinder than the worry: eat the protein, do the training, cover the gaps food cannot, and tune out the hype. Losing muscle is not the price of losing weight, not if you protect it.