North Star Theory

The research library

All research articles.

Browse the full collection, from the latest answers to earlier articles. Find a topic, check when it was verified and follow the evidence.
← Research overview

Showing 73 to 84 of 91 articles · Most recently verified first

Is an elevation training mask worth it?

Last verified

No. Controlled trials show the mask does not mimic altitude: it does not raise how much oxygen your blood carries or beat ordinary interval training, and in one trial wearing it made people stop sooner from breathlessness. At most it works the breathing muscles.

Read more

Is beta alanine worth it?

Last verified

Beta alanine may help some demanding exercise tasks, but the size and relevance of the benefit depend on the test. An average effect size is not a promised percentage improvement in your performance.

Read more

Is blood flow restriction training worth it?

Last verified

Blood flow restriction is not a self-directed workaround for painful or injured joints. Potential training benefits need to be considered alongside individual screening, appropriate prescription and unresolved safety questions.

Read more

Are carbon plate running shoes worth it?

Last verified

A carbon plate alone is not a guarantee of faster running. A buying decision needs evidence for the complete shoe, its fit and intended use; this draft does not yet establish model-specific performance or durability.

Read more

Is citrulline malate worth it?

Last verified

Marginal and uncertain. One review has a dose before training adding about three reps across a session. Another found no effect on strength, and a third flags results that do not agree, plus label problems in some products. A cheap experiment, not a reliable aid.

Read more

Are compression garments worth it?

Last verified

A small, real recovery aid, not a game changer. When researchers pool the studies, compression helps recovery a little, most of all strength after lifting, and slightly raises blood flow back to the heart. Worth it if a snug pair makes your legs feel better. Skip it if not.

Read more

Is creatine safe for your kidneys?

Last verified

The cited short trials provide reassurance for the populations and protocols studied, not a guarantee for every reader. Creatine can influence creatinine-based kidney estimates, but that does not establish why an individual result is abnormal. Do not dismiss a raised creatinine or lower eGFR as a supplement effect without clinical assessment.

Read more

Is fasted cardio better for fat loss?

Last verified

No. Two randomised trials (4 and 12 weeks) found the same fat loss whether cardio was done fasted or fed at matched calories. Training fasted shifts fuel use towards fat in the session, but the body rebalances afterwards and total energy deficit decides fat loss. Do whichever you can sustain.

Read more

Is it too late to build muscle after 40?

Last verified

No. A pooled analysis of about 1,300 people aged 50 and over found an average 1.1 kg lean mass gain from resistance training, plus substantial strength. Gains come a bit slower with age, but the direction is the same as for younger people. Start now.

Read more

Is muscle memory real?

Last verified

Yes, the practical part. You regain lost muscle and strength faster than you first built them: after a 10 week break, a retraining group caught up with one that never stopped. Strength returns fastest because it is largely neural. The cellular mechanism is still debated.

Read more

Is protein powder worth it, and which type should you get?

Last verified

A powder is a convenience, not a requirement: it adds only a little to training gains once your daily protein is already adequate from food. Type matters little at matched protein per serving, whey concentrate for value, isolate for low lactose, soy or a pea rice blend if you avoid dairy.

Read more

Is running bad for your knees?

Last verified

For most people, no. Recreational runners have less knee and hip arthritis than sedentary people and lower odds of a knee replacement, and cartilage adapts to load rather than wearing out. Risk rises with decades of high volume competitive running. It is observational data, not proof.

Read more