Conclusion: Thirty RCTs (70%) were eligible for meta-analysis and all examined muscle mass outcomes. Compared with animal protein, plant protein resulted in lower muscle mass following the intervention (SMD = -0.20; 95% CI: -0.37, -0.03; P = .02), with stronger effects in younger (<60 years; SMD = -0.20; 95% CI: -0.37, -0.03; P = .02) than in older (≥60 years; SMD = -0.05; 95% CI: -0.32, 0.23; P = .74) adults. There was no pooled effect difference between soy and milk protein for muscle mass (SMD = -0.02; 95% CI: -0.20, 0.16; P = .80) (n = 17 RCTs), yet animal protein improved muscle mass compared with no
PubMed 39813010 ↗Muscle Milk
The short answer. There isn't much data on Muscle Milk yet — 8 mentions, 5 with a clear outcome — so treat these numbers as anecdotal. There is a moderate body of research — 59 meta-analyses and 0 trials.
From 8 mentions in total — the rest didn't say how it went and aren't counted.
What Muscle Milk does, according to users
Of the people who reported each effect, the share who said it got better.
What the research says
Systematic reviews and meta-analyses from PubMed, with their published conclusions.
At least one meta-analysis, or 5+ randomized controlled trials. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: By contrast, our meta-analysis showed that co-supplementation with whey protein and vitamin D is effective, particularly in healthy older adults, which is likely owing, we propose, to the correction of vitamin D insufficiency or deficiency. The trial was registered at https://inplasy.com as INPLASY202240167.
PubMed 37196876 ↗Conclusion: WP supplementation during RET is more effective in increasing handgrip strength and skeletal muscle mass in older people with Sarcopenia compared with RET with or without placebo supplementation. However, the effect sizes were small, and the MD did not exceed the minimally important clinical difference. The quality of the evidence was low to very low according, to the GRADE approach. Further research is needed in this field.
PubMed 37571361 ↗Conclusion: Results of this systematic review and meta-analysis suggest that provision of relaxation was associated with an increase in human milk quantity and infant weight gain and a slight reduction in stress and anxiety. Relaxation interventions can be offered to lactating parents who would like to increase well-being and improve milk supply or, where directly breastfeeding, increase infant weight gain.
PubMed 38709505 ↗Dosage people report
As stated by users — not a recommendation. Follow the label or your doctor.
Reported side effects
How often each side effect came up across all reports.
What users say
First-hand experiences, quoted verbatim. We show one positive and one negative where both exist.
“Best tasting protein shakes ive had are Gaspari Myofusion...Muscle Milk and Syntha 6”
“Also I'd strongly advise you to stay off muscle milk. It is a very overpriced product and the same effect can be achieved by mixing your whey protein with Maltodextrin or dextrose.”
Other options for performance
User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 3, 2026. How we rate