Myth busting: does the time you take protein influence muscle growth?

Claudio Viecelli

18.6.2025

Translation: Julia Graham

Strength training is about much more than just muscle gain. It’s like medicine for your body, as it can help prolong a healthy life expectancy [1–6]. In this series, we take a critical look at widespread myths. This time we’re investigating the effects of protein intake.

Strength training is a robust stimulus for muscle growth [7,8]. Combined with protein, it can increase muscle growth, also known as hypertrophy [9]. The practical recommendations for this are 1.6 – 2.2 g protein per kg of body weight [9,10].

So it’s no wonder that the classic protein shake is so popular after a workout. But how important is the timing? Let’s take a look at what the science says. Is it really crucial to drink a protein shake straight after exercise? Or could it even be better to have it beforehand? Perhaps the exact timing doesn’t play such a big role – and we have more leeway than we think?

Effects before and after training show no differences

In 2007, Tipton et al [11] investigated this quandary and wanted to know how protein synthesis behaves in two groups of young men and women who trained 10 sets of 8 repetitions each on the leg extension machine. They differed in that one group consumed 20 g of whey protein an hour before or after training. Protein synthesis was stimulated by whey protein but the timing didn’t play a significant role.

Schoenfeld and their team investigated the same question at a later date [12]. In a study, they investigated how strength and muscle mass develop after 10 weeks of strength training in 21 men with strength training experience. The men were divided into two groups. One cohort consumed 25 g of whey protein and 1 g of carbohydrates right before working out while the other took the same supplement straight after training. Their workouts were twice a week. However, no significant difference was found between the groups in strength and muscle mass.

A meta analysis from 2013 came to a similar conclusion, where researchers concluded that the specific time when protein is taken doesn’t play a significant role. They found that the time window for an anabolic response is probably more than one hour before or after a workout [13].

Effects aren’t dependent on age

In 2020, a comprehensive systematic review with meta analysis was published that examined a central question: what is the role of protein intake and its timing on body composition and strength in healthy adults [13]? The analysis included 65 studies with a total of 2,907 participants aged between 18 and 55 and older adults between 55 and 81. The researchers came to an important conclusion: protein supplementation had a significant effect on muscle mass, both in adults and older people. However, this meta analysis also showed that the timing of protein intake didn’t play a decisive role. This raises the question of whether a targeted intake directly before or after exercising is necessary at all.

At the beginning of last year, the next systematic paper was carried out with a network meta analysis [14]. This included examining 116 studies containing 4,711 participants. This study also showed that protein intake both before a workout and the combination of protein intake before and after exercise can contribute to an increase in muscle mass [14].

It’s the right amount that’s key, not the time

In 2024, Lak and team [15] investigated whether the timing of protein intake in men who do strength training has an influence on the increase in strength or hypertrophy. In this single-blind, randomised clinical trial, 31 young men (24 ± 4 years) trained four to five times a week for eight weeks and completed a whole-body programme. The participants kept six 24-hour food diaries over four consecutive weekdays and two non-consecutive weekends so that their usual protein intake could be determined. In the study, the target daily protein intake was set at 2 g per kg of body weight per day. The two groups differed in that one consumed 25 g of isolated whey protein directly before and after training and the other group consumed the same amount three hours before and three hours after their workout. They consumed the remaining amount of protein during the course of the day via their regular diet. The usual protein intake remained stable for both groups throughout the study.

As expected, protein supplementation led to an increase in strength and muscle mass in both groups, which was independent of the time of intake. There was no significant difference between the groups.

A mixed meal consisting of carbohydrates, fatty acids and proteins can maintain an anabolic effect in the body for up to six hours [16]. If a meal like this is consumed three to four hours before training, immediate protein intake after the workout is less important. However, if you train on an empty stomach, it’s advisable to consume protein immediately afterwards to increase protein synthesis and achieve a positive net balance [17].

Verdict

We know that protein intake is beneficial for strength training. However, strong indications suggest there’s no specific time window for optimal protein intake. The evidence for this is limited. So it’s probably a – widespread – myth.

Citation:

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Claudio Viecelli

Biologe

claudio.viecelli@keyoniq.com

Molecular and Muscular Biologist. Researcher at ETH Zurich. Strength athlete.

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