The Short Version
This claim is false. Multiple peer-reviewed studies consistently show that weekend catch-up sleep does not fully compensate for weekday sleep deprivation. While extra weekend sleep may partially improve some markers — such as sleepiness and certain cardiovascular risk associations — it fails to reverse key deficits in cognitive performance, vigilance, and metabolism. Chronic sleep restriction compounds the problem further. The word "fully" makes this claim unsupportable by current scientific evidence.