ParrotPalProtein shakes on Mounjaro: do you need them, and what to look for
A shake can help on the days food won't go down, but everyday food gives the same protein. Here's how they compare, and how to close your gap.
Shake or food?
Per portion| Per portion | Protein | kcal |
|---|---|---|
| Protein shake, ready to drink (typical)Quick when food won’t go down | 20 g | 130 |
| Skyr, 150 gSpoon it straight from the pot | 16 g | 95 |
| 0% Greek yogurt, 170 g potAdd fruit if you fancy it | 17 g | 95 |
| Cottage cheese, 150 gOn a cracker or with fruit | 15 g | 120 |
| Two medium eggs and a glass of semi-skimmed milk (300 ml)A small breakfast in five minutes | 24 g | 290 |
| Turkey breast slices, 60 gRoll them up, no cooking | 14 g | 60 |
Approximate, from typical UK supermarket labels. Brands vary, so check the label.
Close my gap
Food firstHow many grams of protein are you short on most days?
Spread these across the day: one at each sitting is easier than one big extra. Values are approximate.
Protein on Mounjaro: why it's the hard part
On a small appetite, protein is usually the first thing to slip. Meals get smaller, and the filling, protein-rich part of the plate is often the bit left behind.
That matters because weight lost isn't all fat. In the big GLP-1 trial, about 4 in every 10 kilos people lost weren't fat (STEP 1 body scans: 5.3 kg of 13.6 kg lost was lean mass; Wilding et al., 2021). Lean mass is muscle included, along with organs, connective tissue and water.
Protein, alongside strength training, is part of what helps you hold on to muscle. A review of 49 trials found that, with strength training, extra muscle from more protein levelled off at around 1.6 g per kg of body weight a day (Morton et al., 2018, British Journal of Sports Medicine). That's an average: some people do better on more, up to about 2.2 g per kg, so treat it as a target to reach rather than a ceiling. For comparison, the UK reference nutrient intake for adults is 0.75 g per kg a day, set to prevent deficiency.
ParrotPal's target uses 1.6 g per kg, counting your weight only up to a healthy weight for your height, rounded to 5 g. In practice that's about 25 to 30 g a meal, or four smaller sittings if full meals are hard on a GLP-1.
Should I drink protein shakes on Mounjaro?
You don't have to. A shake is one tool, and it's most useful in two situations:
- Closing a gap. You've eaten what you can and you're still 15 or 20 g short.
- Mornings when food won't go down. A cold drink can be easier than a plate of eggs.
Food first is still the better habit. A pot of skyr or a few slices of turkey give similar protein, and real food brings fibre, vitamins and minerals that a shake may not. Meals also keep the habit of eating properly, which matters for when your appetite comes back.
What our members logged
We compared ParrotPal food diaries from March to August 2026: members who told us they take a GLP-1 medicine such as Mounjaro, and members who don't. Members on a GLP-1 were a little more likely to log a protein supplement, and more of their protein came from one. They logged everyday protein staples a little less often.
| What they logged | On a GLP-1 | Not on one |
|---|---|---|
| Any protein supplement (shake, bar, protein milk or similar) | 53% | 49% |
| Median share of protein from supplements | 5.4% | 2.1% |
| Greek yogurt or skyr | 32% | 38% |
| Chicken breast | 41% | 46% |
| Cottage cheese | 19% | 21% |
| Egg whites | 8% | 12% |
| Less than 1.0 g of protein per kg of body weight | 48% | 35% |
Aggregated and anonymised ParrotPal food diaries, March to August 2026. Food and supplement rows: foods logged at least once by more than 1,000 members on a GLP-1 who logged food. Protein row: several hundred members on a GLP-1 who logged food and a weight, and several thousand who don't take one. GLP-1 use is what members told us. These are patterns in what people logged, not proof of cause.
Even on a GLP-1, supplements were a small slice of the day's protein. Most of it still came from food.
How to choose a protein shake or powder
There's no single right shake, and we don't rank brands. What suits you is the one you'll actually drink. Check these four things on the label:
- About 20 g of protein a serving. That's similar to a pot of skyr. Read the protein per serving, not per 100 g.
- Protein near the top of the ingredients. Ingredients are listed largest first, so milk protein, whey, soya or pea protein should come early.
- The sugar per serving. Some shakes are closer to a milkshake. Compare a few and choose a lower one.
- How it sits with you. On a small appetite, a smaller, thinner drink can be easier. Try a single bottle before buying a multipack.
Powders work the same way. Check the protein per scoop, and remember that mixing with semi-skimmed milk adds protein: about 11 g in a 300 ml glass.
Is collagen a good protein on Mounjaro?
Not as your main source. Collagen is an incomplete protein: it lacks one of the essential amino acids and has little leucine, the amino acid most linked with building muscle. So gram for gram it does less for muscle than dairy, eggs, meat, fish, soya or a milk-based shake.
It's fine as part of your day's protein. Just don't count on a collagen drink or powder to close your gap on its own.
Shakes alongside food, not instead of it
Use a shake to top up a day, not to replace meals. If you find you're living on shakes because food won't go down, or you're struggling to eat enough at all, talk to your prescriber or a dietitian. They can help with a plan that fits you.
What's your own protein number?
Your target depends on your height and weight. The calculator works it out in 10 seconds, and the gap helper on this page will use it. Then see a week of meals built around protein.
Work out my protein See the Mounjaro meal plan Free LeanShield scoreQuestions people ask
Should I drink protein shakes on Mounjaro?
You don't have to. A shake is one easy way to close a protein gap on days when food won't go down, but everyday foods like skyr, Greek yogurt, cottage cheese, eggs, lean meat and fish give similar protein. Many people keep a shake for the hard days and use food the rest of the time.
How much protein should a protein shake have?
About 20 g of protein a serving is a useful guide, similar to a pot of skyr or Greek yogurt. Read the protein per serving, not per 100 g, and check the sugar per serving too.
Can I replace meals with protein shakes on Mounjaro?
We wouldn't. Use shakes alongside food, not instead of it. Meals bring fibre, vitamins and minerals that a shake may not. If you're struggling to eat enough, talk to your prescriber or a dietitian.
Is collagen a good protein on Mounjaro?
Not as your main source. Collagen is an incomplete protein: it lacks one of the essential amino acids and has little leucine, so it does less for muscle than dairy, eggs, meat, fish, soya or a milk-based shake. It's fine as part of your day's protein, but don't count on it for most of it.
What about protein water or protein milk?
Both count towards your day, but the protein varies a lot between products, so check the grams per bottle on the label. Plain semi-skimmed milk gives about 11 g in a 300 ml glass.
Also from ParrotPal
Please read. This page is general information, not medical advice. It isn't tailored to you and doesn't replace advice from your prescriber, GP or dietitian. If you have diabetes, kidney disease, a history of disordered eating or any other medical condition, check with them before changing how you eat or adding supplements. Protein counts are estimates.
Mounjaro® is a registered trademark of Eli Lilly and Company, and Wegovy® of Novo Nordisk. ParrotPal isn't affiliated with or endorsed by either company, and doesn't recommend any shake brand. LeanShield™ is ParrotPal's muscle protection score: it rates the habits linked to protecting muscle, is not a medical device and doesn't measure muscle.