FGF23 is a protein your body makes to control phosphate and vitamin D levels, working mainly through your kidneys and bones. According to Gram Research analysis, this protein gets modified with chemical tags that protect it from breaking down too quickly, and when FGF23 doesn’t work properly, people develop serious mineral imbalances and bone diseases like kidney disease and rare genetic disorders. Multiple enzymes break down FGF23, and new treatments like burosumab block FGF23 to help restore mineral balance.
Your body has a special protein called FGF23 that acts like a manager for two important minerals: phosphate and vitamin D. According to Gram Research analysis, this protein works in your kidneys and bones to keep these minerals balanced, which is crucial for strong bones and healthy body functions. When FGF23 doesn’t work properly, people can develop bone diseases and mineral imbalances. Scientists have discovered how FGF23 is made, how it gets broken down in your body, and how different diseases affect this process. Understanding FGF23 better helps doctors treat conditions like kidney disease and rare bone disorders.
Key Statistics
A 2026 review in Molecular and Cellular Endocrinology identified six major diseases caused by FGF23 dysfunction, including chronic kidney disease, X-linked hypophosphatemia, and hyperphosphatemic familial tumoral calcinosis, each disrupting FGF23 processing in different ways.
Research shows FGF23 forms a complex with its receptors and helper proteins in a specific 1:2:1:1 structure that activates signaling pathways controlling phosphate and vitamin D balance in the kidneys.
Laboratory studies demonstrate that skin cells can produce and secrete FGF23 in response to vitamin D, though whether skin meaningfully contributes to circulating FGF23 levels in humans remains unconfirmed.
Current evidence supports burosumab and selective FGFR inhibitors as emerging treatments for FGF23-related disorders, with additional approaches including C-terminal peptides and enzyme replacement therapy under investigation.
The Quick Take
- What they studied: How the body makes, processes, and uses a protein called FGF23 that controls phosphate and vitamin D levels
- Who participated: This is a review article that examined existing research rather than conducting a new study with participants
- Key finding: FGF23 is a critical control protein that gets modified in specific ways before it can work, and multiple diseases disrupt this process
- What it means for you: Better understanding of FGF23 could lead to new treatments for kidney disease and rare bone disorders, though this is primarily important for people with these conditions
The Research Details
This is a comprehensive review article, meaning scientists examined and summarized all the existing research about FGF23 instead of conducting their own experiment. The researchers looked at how FGF23 is created in bone cells, how it gets modified with chemical tags, how it travels through the body, and how it gets broken down. They also reviewed what happens when FGF23 doesn’t work properly in various diseases.
The review examined multiple treatment approaches, including a drug called burosumab that blocks FGF23, drugs that target FGF23 receptors, and other experimental therapies. By pulling together information from many different studies, the researchers created a complete picture of how this protein works from start to finish.
Review articles are important because they help scientists and doctors understand the big picture. Instead of looking at one small study, reviewers examine hundreds of research papers to find patterns and connections. This approach is especially valuable for complex proteins like FGF23 that involve many different body systems. Understanding how FGF23 works helps doctors develop better treatments for serious conditions like chronic kidney disease and rare genetic bone disorders.
This review was published in a respected scientific journal focused on cell biology and hormones. The authors appear to have expertise in bone and kidney biology. However, because this is a review of existing research rather than a new study, its strength depends on the quality of the studies it examined. Some areas still have gaps in knowledge, particularly about how much different enzymes contribute to breaking down FGF23 in humans.
What the Results Show
FGF23 is a protein made mainly by bone cells that acts as a messenger controlling phosphate and vitamin D levels. The protein gets modified with special chemical tags (called O-glycosylation) that protect it from being broken down too quickly. Another modification (phosphorylation) actually makes it easier to break down, creating a balance that controls how much active FGF23 circulates in the blood.
The protein works by connecting to receptors on kidney cells, with help from a partner protein called α-Klotho. This connection triggers a chain reaction inside cells that tells the kidneys to handle phosphate and vitamin D differently. Multiple enzymes can break down FGF23, including furin and plasminogen activators, though scientists still don’t fully understand which ones are most important in living humans.
The review identified six major diseases caused by FGF23 problems: chronic kidney disease, autosomal dominant hypophosphatemic rickets, hyperphosphatemic familial tumoral calcinosis, X-linked hypophosphatemia, Raine syndrome, and ENPP1 deficiency. Each disease disrupts FGF23 processing or function in different ways, causing mineral imbalances and bone problems.
Interestingly, skin cells can also make and release FGF23 in laboratory experiments, though scientists haven’t confirmed whether skin contributes meaningfully to FGF23 levels in the bloodstream. The response of skin cells to vitamin D depends partly on vitamin D receptors, suggesting that vitamin D directly influences FGF23 production. The review also examined how receptor availability—meaning how many FGF23 receptors are present—affects how strong the signaling response is.
This review integrates recent structural studies showing how FGF23 forms a complex with its receptors and helper proteins. Previous research identified FGF23’s role in mineral balance, but newer studies have revealed the detailed molecular mechanisms of how it’s made and broken down. The review also incorporates emerging treatment approaches like burosumab (a drug that blocks FGF23) and selective receptor inhibitors that weren’t available in earlier reviews.
This review has important limitations. First, it’s based on existing research, so gaps in the literature become gaps in the review. Second, much of the detailed molecular work comes from laboratory experiments or animal studies, which don’t always translate perfectly to how FGF23 works in living humans. Third, the exact contribution of different enzymes that break down FGF23 in humans remains unclear—much of this knowledge comes from cell experiments. Finally, whether skin cells meaningfully contribute to blood FGF23 levels is still unknown.
The Bottom Line
For people with chronic kidney disease or rare bone disorders: Ask your doctor about FGF23 testing and whether treatments like burosumab might help (moderate confidence). For people with normal kidney function: No action needed based on this research. For healthcare providers: Consider FGF23 as a key marker in managing mineral balance disorders (high confidence based on clinical evidence).
People with chronic kidney disease, genetic bone disorders (especially X-linked hypophosphatemia), or unexplained bone pain should discuss FGF23 with their doctors. People with normal kidney function don’t need to worry about FGF23 levels. Researchers studying bone health, kidney disease, and mineral metabolism should understand FGF23 mechanisms.
For people starting FGF23-targeted treatments like burosumab, improvements in bone health and mineral balance typically appear over weeks to months, not days. Long-term benefits require ongoing treatment and monitoring.
Frequently Asked Questions
What does FGF23 do in the body?
FGF23 is a protein that controls phosphate and vitamin D levels by signaling to your kidneys how much of these minerals to keep or remove. It’s made mainly by bone cells and works through special receptors on kidney cells to maintain mineral balance essential for bone health and body function.
What happens when FGF23 levels are too high or too low?
High FGF23 causes the kidneys to lose too much phosphate and vitamin D, leading to weak bones, muscle cramps, and bone pain. Low FGF23 causes phosphate to build up, potentially causing calcium deposits in tissues. Both extremes disrupt mineral balance and bone health.
Can I get tested for FGF23 problems?
Yes, doctors can measure FGF23 levels with a blood test, especially if you have kidney disease or unexplained bone problems. If your FGF23 is abnormal, your doctor can investigate the underlying cause and discuss treatment options like burosumab or other emerging therapies.
Is FGF23 important for people with normal kidneys?
FGF23 is essential for everyone’s mineral balance, but problems with FGF23 mainly affect people with kidney disease or genetic bone disorders. People with healthy kidneys typically don’t need to worry about FGF23 unless they have symptoms of mineral imbalance like bone pain or muscle weakness.
What are the new treatments for FGF23 disorders?
Burosumab is an FDA-approved drug that blocks FGF23 and helps restore mineral balance in certain genetic bone disorders. Researchers are also testing selective FGFR inhibitors, C-terminal peptides, and enzyme replacement therapies, though these are still being studied in clinical trials.
Want to Apply This Research?
- If you have a kidney disorder or bone disease, track your phosphate and vitamin D levels monthly (if your doctor orders tests), noting any changes in bone pain, muscle weakness, or fatigue alongside lab results
- Work with your healthcare provider to monitor FGF23-related symptoms: bone pain, muscle cramps, and fatigue. Use the app to log these symptoms and any medications or supplements affecting mineral balance
- Set monthly reminders to record lab results if you have kidney disease or bone disorders. Track symptom patterns and medication adherence. Share this data with your doctor to optimize treatment
This article reviews scientific research about FGF23 and is for educational purposes only. It is not medical advice. If you have kidney disease, bone pain, muscle weakness, or suspect you have a mineral balance disorder, consult your healthcare provider for proper diagnosis and treatment. Do not start, stop, or change any medications based on this information without talking to your doctor first. Some treatments mentioned (like burosumab) require medical supervision and are not appropriate for everyone.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
