From the Research
The half-life of albumin in the human body is approximately 20 days, or about 3 weeks. This means that it takes about 20 days for half of the albumin molecules in circulation to be degraded and replaced 1. Albumin is the most abundant protein in human blood plasma, synthesized primarily by the liver at a rate of about 10-15 grams per day. Its relatively long half-life contributes to its stable concentration in the bloodstream, typically 3.5-5.0 g/dL in healthy adults. This extended circulation time is due to albumin's molecular structure and its ability to avoid rapid clearance by the kidneys through glomerular filtration. Additionally, albumin that does get filtered is largely reabsorbed in the proximal tubules of the kidneys through a process called tubular reabsorption. The long half-life of albumin is important clinically because it allows this protein to effectively maintain oncotic pressure, transport various substances in the blood, and provide a reservoir of amino acids for the body.
Some key points to consider about albumin half-life include:
- Albumin's long half-life is a result of its size and interaction with the FcRn mediated recycling pathway 1
- The understanding of albumin's half-life is being used to extend the circulatory half-life of drugs that can be engineered to bind to albumin, or are conjugated to, or genetically fused to, albumin 1
- The manipulation of the albumin-FcRn interaction will facilitate the modulation of the circulatory half-life of albumin-enabled drugs, leading to superior pharmacokinetics tailored to the disease state and increased patient compliance 1
It's worth noting that while the provided evidence does not directly address the half-life of albumin, study 1 provides the most relevant and recent information on this topic, and is therefore used as the basis for this answer.