Protein shake before bed: worth it or not?

A protein shake before bed is the simplest way to bridge the seven to ten hours without a meal with amino acids. In the studies on this, casein was almost always in the shaker, usually 30 to 40 g, drunk about 30 minutes before going to sleep^1,2. Whether you need it is decided not by the time of day but by your protein intake over the whole day⁴. Here you will read when casein before bed makes sense, how much belongs in the shaker and how whey and quark compare.

Key takeaways

• Protein before bed: worthwhile when there are more than three hours between your last meal and bedtime, after an evening workout, or when your daily protein intake stays below 1.4 to 2.0 g per kilogram of body weight.
• Casein is the protein for the night: slowly digested, amino acids over around seven hours. Whey protein works fast and belongs around training.
• Proven: 40 g of casein before sleep increased muscle protein synthesis during the night; 27.5 g of protein every night for 12 weeks brought more strength and muscle cross-section.
• With us, 30 g of casein powder deliver 22 to 24 g of protein at 104 to 118 kcal; the bestseller is the 100% Casein Protein from GN Laboratories.

Is casein before bed worthwhile?

Yes, for everyone who trains for muscle growth and does not want to leave the night unused as the longest phase without protein. During sleep the body repairs the muscle tissue you stressed in strength training; for that, the muscles need amino acids as building blocks. If nothing comes in for seven to ten hours, the body falls back on its own protein (muscle breakdown). Casein before sleep secures the supply for hours: the milk protein flocculates in the stomach and is digested slowly⁵, the level in the blood stays elevated all night¹.

Some perspective belongs here: total protein intake spread over the day counts more than the timing of a single intake⁴. Spreading it over three to five meals is the second factor. Anyone who already reaches 1.6 g per kg of protein intake with three protein-rich meals gets an extra from the shake before sleep, not a leap; anyone below that collects the missing rest in the evening. That is why casein before bedtime makes sense for most athletes and is a must for no one.

Is protein before bed good? This is what the studies show

Yes. Protein before bed is digested during sleep, the uptake of amino acids runs all night, and the muscles make use of them. In Res et al., 16 young men trained in the evening and drank 40 g of casein or a placebo 30 minutes before sleep: protein synthesis in the body rose, the protein balance became positive, and muscle protein synthesis was around 22 % above placebo¹. The same research group around van Loon tested the effect over a longer period in 2015: 44 young men trained for 12 weeks, one group received 27.5 g of protein with 15 g of carbohydrates every night, the other a placebo. The participants in the protein group gained more strength (+164 kg compared with +130 kg). The cross-section of the thigh muscle grew almost twice as much, in other words: more muscle growth².

The 2019 review by the same researchers sums it up: protein before sleep does not change resting energy expenditure and enhances the adaptation to strength training³. A protein shake before sleep is therefore no miracle cure, but a reliable building block for recovery and muscle growth. Protein contributes to a growth in muscle mass and to the maintenance of muscle mass⁶, and the night is the longest period in which you otherwise take in nothing. Milk protein also supplies tryptophan, the amino acid from which the body forms serotonin and melatonin.

How much casein before bed?

30 to 40 g of casein: this is the dose the studies worked with, and it is also what the International Society of Sports Nutrition names for intake before sleep^1,4. The 12-week study managed with 27.5 g². One serving with us (30 g of powder) delivers 22 to 24 g of protein and is therefore on a par with the long-term study. Anyone who wants 40 g takes one and a half servings; more brings nothing according to the current research. Count the shake as a supplement within your daily protein intake, and drink it ideally in the last hour before going to bed. The calculator translates that to your weight and your evening.

Which protein before bed: casein or whey protein?

Casein. Whey protein reaches the blood after 40 to 60 minutes and is used up after two to three hours; the night shake keeps delivering for around seven hours⁵. For a night of seven or eight hours, the slowly digested milk protein is the right tool for recovery and protein synthesis. That is why it appears in almost all studies on pre-sleep protein³. It is a question of speed, not quality: whey remains the protein right after training, the combination of both covers training and night. The guide Whey or casein shows the advantages in detail.

Casein with us: The 100% Casein Protein from GN Laboratories (900 g, made in Germany) is our bestseller: 62 % of casein orders in the last 90 days (as of August 2026), most-chosen flavour Chocolate Crema, 4.89 stars in the shop reviews. If you tolerate lactose poorly, take Micellar Casein from PEAK with lactase (76 to 80 g per 100 g); if you want to switch between chocolate, vanilla and strawberry, 100% Casein from Stacker2 (75 to 79 g). All three are in the casein powder overview.

Should you still drink a protein shake in the evening?

Yes in three cases, no in one. Taking it pays off when more than three hours lie between your last meal and bedtime. The same applies if you trained in the evening and your body recovers during the night, or if your protein intake for the day stayed below 1.4 to 2.0 g per kg⁴. It then replaces the snack in front of the TV and delivers protein instead of crisps. You can skip it if you had a protein-rich meal at 9 pm and sleep at 11 pm; the casein from that meal is still on its way anyway. A protein shake in the evening is not a question of right or wrong, but of gap or no gap in your diet. With shift work and long office days you do best with two servings: one in the afternoon, one before sleep. That split also covers a 16-hour day.

What should you eat before bed for muscle growth?

Ideally something with 25 to 40 g of slowly digestible protein and little fat, so the night stays calm. The food for that is almost always a dairy product: a casein shake (about 23 g of protein), 250 g of low-fat quark (30 g), 300 g of skyr or Greek yoghurt (27 to 33 g) or 200 g of cottage cheese (24 g). All of them contain mainly casein; cow's milk delivers 80 % of its protein in this form. Cheese has it too, but with far more fat; eggs, meat and fish are good protein sources, but are digested faster and sit heavier as a late meal. Shake or cottage cheese is a matter of taste, not of effect: in active women, cottage cheese and a casein shake with 30 g of protein each before sleep differed neither in resting energy expenditure nor in appetite the next morning⁷. The advantages of the shake are practical: ready in a minute, without the lactose of quark. What casein exactly is and which types exist is explained in the casein guide.

Casein before bed and weight loss

A shake before sleep does not make you fat, and it does not make you slim; both are decided by your calorie balance at the end of the day. The worry that late protein adds fat does not stand up to the studies: in active women the night shake had no effect on resting energy expenditure (the metabolism at rest) or on appetite⁷. The 2019 review reaches the same conclusion³. When dieting, the phase with a calorie deficit, casein in the evening above all plays a role as a protein supplier: around 23 g of protein for about 110 kcal, plus the slow digestion that keeps the stomach busy for hours. Protein contributes to the maintenance of muscle mass⁶, and that is exactly the goal in a deficit: lose fat, keep the muscle. Plan the shake into the day's diet, not on top of it. How the evening shake fits into a diet is covered in the article Casein for weight loss.

How to make the night shake

30 g of casein powder in 250 to 300 ml of water or low-fat milk, 20 seconds in the shaker, done. The powder thickens when mixed, so use a little more liquid than with whey protein; with milk it becomes creamier and additionally delivers calcium. If you like it firmer, mix the amount with 100 ml into a casein pudding and eat it with a spoon. Drink it ideally half an hour to an hour before going to bed, not in bed itself, then it sits lightly in the stomach. A 900 g tub lasts a month at one serving a day.

Conclusion: casein before sleep is the easiest protein win of the day

Casein before bed is not a must, but it makes sense as soon as it closes a gap: a long break after dinner, an evening workout or a protein intake below the daily target⁴. Casein is the right protein for it, 30 g of powder the right amount, the last hour before going to bed the right time. Whey stays reserved for training. Anyone who keeps this up for four weeks knows why the evening shake has become a ritual for many athletes and why good nutrition in sport is above all a habit. You will find the right tub in the casein powder overview; at the very front is the 100% Casein from GN Laboratories.

Goes well with it: 100% Dairy Whey (GN Laboratories) for the time after training and the GN Wave Shaker 700 ml, in which 30 g of casein mix lump-free with 300 ml of water.