Educational Content Disclaimer
This article is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Muscle pain while taking a statin has many possible causes — your genetics is only one factor among many. Do not stop, reduce, or change your statin medication based on a DNA result alone. Stopping a statin abruptly can significantly increase cardiovascular risk. If you have concerns about muscle symptoms, please speak with your doctor or pharmacist before making any changes to your medication.
Short answer: Yes — a common variant in your SLCO1B1 gene, rs4149056 (the C allele), slows how fast your liver clears statins from your blood, which raises the odds of statin-related muscle pain (myalgia) — most strongly with simvastatin at higher doses. It is a risk factor, not a diagnosis: plenty of carriers tolerate statins with no trouble. The gene is already sitting in your 23andMe or AncestryDNA raw data, so you can check your own SLCO1B1 rs4149056 genotype with AskMyDNA in a couple of minutes (your first question is free, no card required). Always talk to your doctor before changing any medication.
What Is the SLCO1B1 Gene and Why It Matters for Statins
Your body does not just absorb medications — it also has to clear them. The SLCO1B1 gene encodes a protein called OATP1B1, a transporter that sits on the surface of liver cells (hepatocytes). Its job is to pull drugs out of the bloodstream and into the liver, where they can be processed and eventually eliminated from the body.
Statins — drugs like simvastatin, atorvastatin, and rosuvastatin — rely heavily on this transporter to move from the blood into the liver, which is where they do most of their cholesterol-lowering work. OATP1B1 is essentially the liver's front door for these medications.
When OATP1B1 works normally, statins enter the liver efficiently, do their job, and clear out of circulation relatively quickly. When the transporter works less well — due to a common genetic variant in SLCO1B1 — statins can linger longer in the blood and muscle tissue. That extended exposure is one reason why certain people are more prone to statin-related muscle symptoms.
This is not obscure pharmacogenomics. The association between SLCO1B1 and statin muscle side effects has been replicated in large studies and is recognized by the Clinical Pharmacogenomics Implementation Consortium (CPIC), which issues clinical guidelines on how to use genetic information in prescribing decisions.
How SLCO1B1 Affects Statin Side Effects
Statin-associated muscle symptoms (SAMS) are the most commonly reported side effect of statin therapy. They range from mild, transient muscle aches (myalgia) to — in rare cases — more serious muscle breakdown (myopathy, rhabdomyolysis). Most people who experience muscle discomfort on a statin have a mild, reversible form.
The mechanism connecting SLCO1B1 to muscle risk is straightforward: if OATP1B1 uptake into the liver is reduced, more of the statin remains in circulation. Higher plasma concentrations of the statin mean greater exposure for muscle tissue, and that increased exposure correlates with higher rates of muscle symptoms.
This does not mean SLCO1B1 is the only factor. Muscle symptoms on statins are multifactorial — dose, statin type, drug interactions, thyroid function, vitamin D levels, exercise, age, sex, and other genetic variants all play a role. (Women, for instance, tend to report statin-associated muscle symptoms somewhat more often than men.) SLCO1B1 is one well-studied piece of a more complex picture.
It is also worth emphasizing what the evidence does and does not show. The strongest association is between SLCO1B1 and simvastatin — particularly at higher doses (40–80 mg). The relationship is less pronounced for statins that depend less on OATP1B1 transport, such as rosuvastatin or fluvastatin. This matters clinically: if your doctor knows your SLCO1B1 status, they have options.
Understanding the SLCO1B1 rs4149056 Variant
The variant most commonly tested is rs4149056 (also written as c.521T>C, or p.Val174Ala). It falls on the SLCO1B1 gene and results in an amino acid change in the OATP1B1 protein that reduces its transport activity. The C version of this variant is sometimes called the SLCO1B1*5 allele.
Because you inherit one copy of most genes from each parent, you carry two copies of this position — your "genotype" is the combination of those two copies.
| Genotype | Transporter Function | Statin Myopathy Risk | Approximate Frequency (European ancestry) |
|---|---|---|---|
| TT (T/T) | Normal | Baseline (lowest) | ~73% |
| TC (T/C) | Intermediate (one reduced-function copy) | Moderately increased | ~24% |
| CC (C/C) | Low (two reduced-function copies) | Highest, especially at higher doses | ~3% |
A few important nuances:
- The C allele is found in roughly 15% of people with European ancestry. It is less common in people of East Asian ancestry and varies across African-ancestry populations — population data for rs4149056 is available at dbSNP rs4149056.
- Having a TC or CC genotype does not mean you will experience muscle problems. Many people with these genotypes tolerate statins without any issues.
- Having a TT genotype does not guarantee you will be symptom-free. Muscle symptoms on statins occur for many reasons unrelated to SLCO1B1.
The genotype is a piece of context — a factor worth knowing, not a diagnosis.
How to Download Your Raw DNA Data
If you have already taken a consumer DNA test, your raw data file is the underlying dataset that contains individual SNP readings — including rs4149056. Here is how to retrieve it from the major platforms:
23andMe: Log in → menu (top right) → Browse Raw Data → Download Raw Data. Select the full file and download. You will receive a .txt file (tab-separated).
AncestryDNA: Log in → DNA → Settings → Download Raw DNA Data. You will receive a .zip containing a .txt file.
MyHeritage: Log in → DNA → Manage DNA Kits → Download (next to your kit). You will receive a .zip with a .csv file.
All three formats are plain text files once unzipped. For more context on what to do with these files after downloading, see our guide: What to Do With Your 23andMe Raw Data After the Bankruptcy.
Finding SLCO1B1 in Your Raw Data File
Once you have your raw data file open (unzip it first if it came as a .zip), you are looking for the rsID rs4149056.
Using a text editor (macOS TextEdit, Windows Notepad):
Open the file. Use Find (Cmd+F or Ctrl+F) and search for rs4149056. The line will look something like:
rs4149056 6 10912060 TC
The last column is your genotype — in this example, TC.
Using Terminal (macOS/Linux):
grep rs4149056 your_genome_file.txt
Using a spreadsheet (Excel, Google Sheets):
Import the file as tab-delimited, then use Ctrl+F to search for rs4149056.
The genotype you see will be two letters: TT, TC, or CC. Match it to the table above.
Note: 23andMe's raw data reports genotypes on the forward strand. Strand orientation matters for interpreting SNPs, but for rs4149056 in 23andMe's format, TC in the file corresponds to a TC genotype as described above.
For a broader overview of other sites that can help you interpret your raw DNA file, see: Best DNA Upload Sites 2026.
What Your SLCO1B1 Result Means (and Doesn't Mean)
If your genotype is TT: You have two copies of the normal-function allele. Your OATP1B1 transporter is expected to work at standard capacity for statin clearance. Your genetic risk for SLCO1B1-related statin muscle symptoms is at the baseline level. This does not rule out muscle symptoms from other causes.
If your genotype is TC: You carry one copy of the reduced-function allele. Your transporter activity is intermediate. Studies suggest a moderately elevated risk of muscle symptoms compared to TT — but many people with TC tolerate statins without problems. This is worth mentioning to your doctor if you are experiencing muscle aches, especially on higher statin doses.
If your genotype is CC: You carry two copies of the reduced-function allele. CPIC guidelines flag this genotype as carrying the highest genetic risk for SLCO1B1-related statin myopathy, particularly with simvastatin at doses of 40 mg or higher. This does not mean you cannot take statins — it means the conversation with your prescriber is especially worthwhile. Your doctor may consider a different statin, a lower dose, or monitoring your creatine kinase (CK) levels.
What this result does NOT mean:
- It is not a reason to stop your statin. Statins reduce heart attack and stroke risk — for many people, that benefit is substantial and well-established.
- It is not a diagnosis of myopathy or any muscle condition.
- A single SNP does not capture the full picture of your statin pharmacogenomics. Other genes (CYP3A4, ABCB1, and others) also influence statin metabolism.
- Muscle pain you are experiencing right now may have nothing to do with genetics — overexertion, flu, low vitamin D, or other medications are all common causes.
The right response to a TC or CC genotype is a conversation with your doctor or pharmacist — not a unilateral decision.
Statins Differ: Not All Are Equally Affected
One of the most actionable things to understand is that SLCO1B1's impact is not the same across all statins. OATP1B1 is the primary transporter for some statins and plays a smaller role for others.
| Statin | SLCO1B1 Sensitivity | Notes |
|---|---|---|
| Simvastatin | High | Strongest association; CPIC guidelines specifically address this combination; highest-dose regimens carry the most risk for CC carriers |
| Atorvastatin | Moderate | Partial OATP1B1 dependence; less sensitive than simvastatin |
| Pravastatin | Low–Moderate | Some OATP1B1 involvement but generally lower sensitivity |
| Rosuvastatin | Low | Less dependent on OATP1B1 for hepatic uptake; often considered an alternative |
| Fluvastatin | Low | Minimal OATP1B1 dependence |
This table illustrates why a prescriber who knows your SLCO1B1 genotype may prefer rosuvastatin or pravastatin over simvastatin for a patient with a CC genotype — not because the others are risk-free, but because the genetic risk signal is smaller. That is a decision for your doctor, who can weigh it against your cholesterol levels, cardiovascular risk, tolerability, and other medications.
How Testing Platforms Handle SLCO1B1
| Platform | Covers rs4149056 in Raw Data | Dedicated SLCO1B1 or Statin Report |
|---|---|---|
| 23andMe (v5 chip) | Yes | No — raw data only, no consumer statin report |
| AncestryDNA | Yes | No |
| MyHeritage | Yes | No |
| Promethease | Yes (via SNPedia lookup) | Shows rs4149056 entry with literature summary |
| SelfDecode | Yes | Yes (paid subscription) |
| AskMyDNA | Yes | Via conversation — upload your genome file and ask directly |
For a walkthrough of how to interpret a Promethease report that includes SLCO1B1, see: How to Read Your Promethease Report.
If you want a conversational, question-and-answer approach to your own raw data, you can upload your genome file to AskMyDNA and ask: "What's my SLCO1B1 rs4149056 genotype?" Your first question is free, with no credit card required.
FAQ
Is muscle pain on a statin always caused by my SLCO1B1 genotype?
No. Statin-associated muscle symptoms are common and have multiple causes — dose, drug interactions, hypothyroidism, vitamin D deficiency, and physical exertion all contribute. SLCO1B1 explains some of the genetic predisposition but not all of it. Many people with TC or CC genotypes experience no muscle symptoms at all, and many TT individuals do experience aches. SLCO1B1 status is one factor for your doctor to consider alongside your full clinical picture.
My 23andMe raw data shows rs4149056 as TC. Should I stop my simvastatin?
No. Do not change or stop your medication based on a DNA result alone. TC does indicate intermediate OATP1B1 function, which is associated with moderately elevated risk — but many TC individuals tolerate simvastatin well. The right step is to share this information with your prescribing physician. They may continue your current regimen with monitoring, discuss dose adjustments, or consider a statin with lower SLCO1B1 sensitivity. Stopping a statin abruptly without medical guidance can increase your cardiovascular risk.
Does AncestryDNA include SLCO1B1 in its results?
AncestryDNA genotypes rs4149056 on its standard chip, so the data is present in your raw download file. However, AncestryDNA does not provide a consumer-facing SLCO1B1 or statin health report — you would need to find the variant in the raw data file yourself (see the section above on how to do that) or use a third-party interpretation tool.
Can my doctor order a proper pharmacogenomics test for SLCO1B1?
Yes. Clinical pharmacogenomics panels ordered through a laboratory (such as GeneSight, Tempus, or hospital-based PGx panels) can test SLCO1B1 and typically provide CPIC-guided clinical interpretation. These tests are ordered by a physician and in some cases covered by insurance, particularly if you have documented statin intolerance. Your doctor can advise whether this is appropriate for your situation.
What does it mean if I have a CC genotype but have been taking simvastatin with no problems?
It means you are among the people with reduced OATP1B1 function who do not develop muscle symptoms — which is entirely possible. The CC genotype raises risk at a population level; it does not guarantee symptoms for every individual. If you are tolerating your current statin well and your doctor is satisfied with your cholesterol management, your regimen may not need any change. Mention your genotype to your doctor as useful background information.
I found rs4149056 in my raw data but it shows different letters than TT, TC, or CC. What happened?
A few things could explain this. Raw data files from different platforms may report genotypes on the forward or reverse DNA strand, which would flip the letters (so what appears as AA could represent TT on the opposite strand, and GA could represent TC). If you see only one letter listed (e.g., just "T"), it may indicate a no-call or low-confidence read at that position. A tool like Promethease or AskMyDNA can handle strand orientation for you — or you can ask your platform's support team which strand convention they use.
Conclusion
The SLCO1B1 gene and its rs4149056 variant represent one of the better-characterized examples of how a common genetic difference can influence how a widely prescribed medication behaves in your body. If you carry the C allele — particularly in a CC genotype — your liver's ability to clear statins from the blood is reduced, which can translate to higher muscle exposure and, for some people, a greater chance of muscle symptoms.
That is worth knowing. It is not a reason to panic, and it is certainly not a reason to stop a medication that may be protecting your heart. It is a conversation to have with your doctor — one where a single data point from your raw DNA file becomes part of a broader, more informed discussion about which statin and which dose is the right fit for you.
If you want to explore your own raw data, AskMyDNA lets you upload your genome file and ask specific questions about variants like rs4149056. Start with your first question free — no credit card needed.