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Cp9.0
Casein Protein Research
Likely helpsHigh safety
42 peer-reviewed studies
What the evidence says
Likely helps
Casein Protein appears to help in 3 of 3 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 1997–2026 with a typical study size of 32 participants.
Based on 42 studies · 3 meta-analyses · 35 RCTs · 3,364 total participants
Confidence
High
What the studies found
3helped· 39 more without graded effect data
By outcome
Lean body mass & muscle growthReduced muscle breakdown, sustained muscle protein synthesis · 4-8 weeks
Mostly mechanism / observational24 studies
RecoveryOvernight muscle recovery and repair · Overnight (8 hours)
11 studies in the last 5 years · Latest meta-analysis: 2026
199720112026
1Meta-AnalysisCited 10×n=1,851 · large study2023
The findings of this study suggest that supplementation with MP may improve glycemic control in adults by reducing the values of fasting insulin, FBG, and HOMA-IR.
Mohammadi S et al. · Nutrition journal (2023)
The findings of this study suggest that supplementation with MP may improve glycemic control in adults by reducing the values of fasting insulin, FBG, and HOMA-IR.
Additional trials with longer durations are required to confirm these findings.
4Digestive health effectsSystematic ReviewCited 49×2019
Human-based evidence from clinical trials and epidemiological studies published prior to October 2017 provides moderate certainty for adverse digestive health effects of A1 β-casein compared with A2 β-casein but low or very low certainty for other health effects.
Küllenberg de Gaudry D et al. · Nutrition reviews (2019)
Human-based evidence from clinical trials and epidemiological studies published prior to October 2017 provides moderate certainty for adverse digestive health effects of A1 β-casein compared with A2 β-casein but low or very low certainty for other health effects.
These conclusions may change in the future, given the emergent nature of this topic and the ongoing research in this area.
5Systematic ReviewCited 6×n=11 · very small study2021
A summary of the main findings shows limited to no effects on metabolism or appetite when ingesting 24-48 g of casein 30 min before sleep, but data are limited, and future research is needed to clarify the relationships observed.
Dela Cruz J et al. · Nutrients (2021)
However, it remains unclear what the effect of this nutritional strategy is on non-muscular parameters such as metabolism and appetite in both healthy and unhealthy populations.
The purpose of this systematic review is to understand the effects of pre-sleep casein protein on energy expenditure, lipolysis, appetite, and food intake in both healthy and overweight or obese individuals.
A systematic review following PRISMA guidelines was conducted in CINAHL, Cochrane, and SPORTDiscus during March 2021, and 11 studies met the inclusion criteria.
These results suggest that hemp protein consumption, as well as in combination with bioactive peptides, may have a role in the dietary management of hypertension.
Samsamikor M et al. · The American journal of clinical nutrition (2024)
These results suggest that hemp protein consumption, as well as in combination with bioactive peptides, may have a role in the dietary management of hypertension.
This trial was registered at clinicaltrials.gov as NCT03508895.
The simultaneous consumption of casein and probiotics significantly improved anaerobic power, isokinetic strength, and lower-body muscular endurance in male soccer players.
Sadeghi R et al. · Journal of the International Society of Sports Nutrition (2025)
The current study's findings indicated that APT-180°/s (ext) significantly increased in CAS (p = 0.008) and PRO+CAS (p = 0.003) compared to PLA.
Additionally, the Wall-squat test demonstrated a significant increase in PRO+CAS compared to PLA (p = 0.001) and PRO (p = 0.001).
The simultaneous consumption of casein and probiotics significantly improved anaerobic power, isokinetic strength, and lower-body muscular endurance in male soccer players.
Consumption of milk containing A2 β-casein only is associated with fewer GI symptoms than consumption of conventional milk in lactose maldigesters.
Ramakrishnan M et al. · Nutrients (2020)
In an analysis of the 25 LI subjects, total symptom score for abdominal pain was lower following consumption of milk containing A2 β-casein only, compared with conventional milk (p = 0.004).
Post hoc analysis with lactose maldigesters revealed statistically significantly improved symptom scores (p = 0.04) and lower hydrogen production (p = 0.04) following consumption of milk containing A2 β-casein only compared with conventional milk.
Symptoms of GI intolerance and breath hydrogen concentrations were analyzed for 6 h after ingestion of each type of milk.
12Gait speed and mitochondrial functioningRCTCited 15×n=82 · small study2021
We conclude that a 12-week intervention with the novel supplement improved walking performance both during short and long distance as compared to a standard supplement, which can largely be explained by increased mitochondrial functioning in the group receiving the novel supplement.
Grootswagers P et al. · Aging (2021)
Likely real
Both groups showed significant increases in body mass.
Fat mass increased significantly more in the standard than the novel supplement group (time*treatment effect P=0.045).
The novel supplement group showed a larger improvement in walking performance on distances of 4m (treatment x time interaction P=0.048) and 400m (treatment x time interaction P=0.038) than the standard treatment group.
Both the IBS-SSS score (p = 0.001) and total symptom score reported daily (p = 0.002) were significantly reduced when participants consumed the hydrolysed product.
Flatulence (p = 0.01) and heartburn (p = 0.03) decreased when consuming the hydrolysed product but not when drinking the control product.
No significant differences in the levels of inflammatory markers (tumor necrosis factor alpha, TNF-α and interleukin 6, IL-6), intestinal permeability (fatty acid binding protein 2, FABP2) or immune activation (1-methylhistamine) were detected between the treatment periods.
Protein processing can strongly modulate the post-prandial rise in plasma amino acid bioavailability in vivo in humans.
Trommelen J et al. · Nutrients (2020)
Plasma total amino acids iAUC were higher following the ingestion of XL-CAS when compared to Ca-CAS (294 ± 63 vs. 260 ± 75 mmol·L-1, p = 0.006), with intermediate values following Mi-CAS ingestion (270 ± 63 mmol·L-1, p > 0.05).
In conclusion, cross-linked sodium caseinate is more rapidly digested when compared to micellar casein and calcium caseinate.
Protein processing can strongly modulate the post-prandial rise in plasma amino acid bioavailability in vivo in humans.
Pre-sleep protein intake does not affect next-morning appetite and energy intake and is therefore a viable strategy to increase daily protein intake in an older population.
Morehen S et al. · Nutrients (2019)
Next-morning appetite, energy intake, resting metabolic rate (RMR), respiratory exchange rate (RER), and plasma acylated ghrelin, leptin, glucose, and insulin concentrations were assessed.
No between-group differences were observed for appetite and energy intake at breakfast.
Furthermore, RMR, RER, and assessed blood markers were not significantly different between any of the treatment groups.
Protein supplementation after exercise and before sleep does not further augment the gains in whole-body oxidative capacity and endurance exercise performance after chronic endurance exercise training in recreationally active, healthy young males.
Jonvik KL et al. · Medicine and science in sports and exercise (2019)
Endurance exercise training induced an 11% ± 6% increase in V˙O2max (time effect, P < 0.0001), with no differences between groups (PRO, 48 ± 6 to 53 ± 7 mL·min·kg; PLA, 46 ± 5 to 51 ± 6 mL·min·kg; time-treatment interaction, P = 0.50).
Time to complete the time trial was reduced by 14% ± 7% (time effect, P < 0.0001), with no differences between groups (time-treatment interaction, P = 0.15).
Muscular endurance increased by 6% ± 7% (time effect, P < 0.0001), with no differences between groups (time-treatment interaction, P = 0.84).
18Insulin and glucagon secretionRCTCited 26×n=122 · medium study2018
PP elicits greater postprandial increases in glucagon than does CP and consequently requires higher insulin to control glucose metabolism, which appears to be related to the rate of amino acid appearance.
Markova M et al. · The American journal of clinical nutrition (2018)
Huge benefit
← WorseNo effectBetter →
Total areas under the curve after CP were significantly lower than after the PP lunch by 40% for insulin and 23% for glucagon.
Indexes of insulin sensitivity and secretion were significantly improved for the second CP MTT.
The ingestion of PP resulted in significant increases in amino acids after both meals, with a decline between meals.
Both NT and DT protein consumption as part of a 24-h nutrition approach are effective for increasing strength and hypertrophy.
Joy JM et al. · Journal of the International Society of Sports Nutrition (2018)
Both NT and DT protein consumption as part of a 24-h nutrition approach are effective for increasing strength and hypertrophy.
The results support the strategy of achieving specific daily protein levels versus specific timing of protein ingestion for increasing muscle mass and performance.
In conclusion, 48 g CP elicited favorable changes in morning RMR, with only trivial changes in RE performance.
Madzima TA et al. · Nutrients (2018)
RE was performed on six machines for 2 sets of 10 repetitions, and a 3rd set to failure at 60% of one-repetition maximum to calculate RE volume (weight lifted × sets × repetitions).
Compared to the PLA, 48 g CP had a likely increase in RMR (4.0 ± 4.8%) and possibly trivial (1.1 ± 7.0%) effect on RE volume.