What to avoid when taking creatine

In this article:

• Can you mix creatine with medication?
• How creatine works
• Medications to avoid
• Mixing with other supplements
• Symptoms of a bad interaction
• How to safely take creatine

In this article

• Can you mix creatine with medication?
• How creatine works
• Medications to avoid
• Mixing with other supplements
• Symptoms of a bad interaction
• How to safely take creatine

As one of the most-studied supplements on the market, creatine is highly effective at improving muscle strength and athletic performance. Taking creatine has been shown to increase high-intensity exercise capacity by 10% to 20%. Other possible benefits of creatine may include improving brain function and potentially improving certain nervous system conditions.

Creatine is generally considered safe for most people to take. However, that doesn’t mean you should consume it blindly. If you want to get the most out of it for both performance enhancement and safety, make sure you talk to your provider about the supplements or medications to avoid and what to use with caution. 

Can you mix creatine with your current meds?

If you’re wondering whether you can mix creatine supplements with the medications you currently take, the answer is: “It depends.”

“For most healthy adults, creatine is one of the safest and most researched supplements you can take,” says registered dietitian Ashley Kitchens, RDN, owner of Plant Centered Nutrition in Durham, North Carolina. “As a CrossFit athlete, I’ve taken creatine for years, and I can attest to the research and personal experience.”

If you’re taking diuretics, NSAIDs, or medications that could affect your kidney function, talk with your healthcare provider before starting creatine. It may be safe to take alongside careful monitoring, or your provider may recommend avoiding the supplement.

How creatine interacts with your body

Your liver, pancreas, and kidneys produce creatine every day. You can also get it from supplements, seafood, and red meat. It’s a compound made from amino acids that’s transported to tissues in your body that need a lot of energy, like your skeletal muscles. 

Most of the creatine in your body is stored in muscle cells. When creatine enters those cells, it draws in water via osmosis. This is why some people experience a slight weight gain; it’s due to intracellular water retention, which isn’t the same as bloating or swelling. 

“Creatine can give the illusion of water retention, but the retention actually occurs inside the cell, not outside the cell,” explains Erika Gray, Pharm.D., founder and chief medical officer at ToolBox Genomics.com. “From this increased intracellular hydration, muscles look larger, have increased muscle fiber volume, and often increase the amount of weight they lift.”

Inside your muscle cells, creatine exists in two forms: creatine and phosphocreatine. Phosphocreatine (also known as creatine phosphate) helps generate ATP (adenosine triphosphate), which is your body’s primary source of energy.

Your body breaks down about 1% to 2% of its creatine every day. Your body converts creatine into creatinine and excretes it through urine. To simply maintain creatine stores, research suggests most people may need to take about 2 to 3 grams of creatine daily, though this can vary based on body size and muscle mass.

Medications to avoid with creatine

Certain groups of people should speak to a provider before starting creatine, according to Mark Kovacs, Ph.D., a performance physiologist at the Kovacs Institute in Atlanta, Georgia. That includes pregnant and breastfeeding people, older adults, those with kidney issues, and people with certain metabolic conditions. 

While there aren’t any clear drug interactions with creatine, there are some medications that could lead to adverse effects. Therefore, exercise caution and get medical advice from your healthcare provider if you’re on any of the following medications:

1. NSAIDs

“If you’re taking NSAIDs like ibuprofen regularly and alongside consistent creatine use, this could increase stress on your kidneys,” explains Kitchens. 

NSAIDs, or nonsteroidal anti-inflammatory drugs, have been linked to an increased risk of acute kidney injury. While occasional use is considered safe, regular or high-dose use of NSAIDs could put strain on your kidneys. If you layer creatine on top of that, you could create additional unnecessary stress, especially if you aren’t well-hydrated. 

2. Medications that affect kidney function

Your kidneys are responsible for clearing creatinine from the body. If you have impaired kidney function or you’re taking medication that affects how your kidneys work, you should consult with a healthcare provider before taking creatine. 

Some medications, like lisinopril or losartan, are commonly used to protect kidney function. In healthy individuals, these drugs are generally considered safe to use alongside creatine with monitoring from a healthcare professional. 

However, if you have chronic kidney disease (CKD) or take a medicine that significantly impacts your kidneys’ workload, like furosemide or cyclosporine, taking creatine could potentially add strain to your kidneys. 

3. Diuretics

A diuretic’s job is to help your kidneys remove excess fluid. If you’re taking a diuretic like hydrochlorothiazide, your urine output increases, which can lower the total amount of water in your body. 

Creatine pulls water into your muscle cells to support energy production while you exercise. While creatine doesn’t compete with a diuretic for water, using both at the same time could increase your risk of dehydration if you aren’t consuming enough fluids.

4. Other medications that affect kidney health 

Some medications can affect kidney function, particularly when taken at high doses or for long periods. Combining these with creatine could lead to unnecessary and potentially harmful effects, and even kidney damage. These include:

• Some antibiotics, like gentamicin
• Chemotherapy drugs like cisplatin
• Immunosuppressants like tacrolimus

These drugs may inadvertently affect the kidneys through various mechanisms. If you’re taking any of these medications, make sure you speak with your provider before starting creatine. 

5. Medications that increase glucose sensitivity

There is some evidence that suggests that creatine can affect glucose metabolism. However, as researchers note, the clinical trials on this topic are smaller-scale and exploratory. If you take a drug that affects your glucose levels, instead of avoiding creatine altogether, speak with your provider. 

“Since creatine may improve insulin sensitivity, anyone taking a drug like metformin and creatine should monitor their glucose levels closely in case glucose levels decrease too much,” says Dr. Erika Gray.

Mixing creatine with other supplements

Creatine may interact with more than just prescription drugs. There are some dietary supplements you may want to use with caution while taking creatine.

Caffeine

No, you don’t have to skip that cherished cup of coffee in the morning if you’re taking creatine. Most research shows that caffeine does not cancel out the effects of creatine or diminish its effectiveness. However, if you have large doses of creatine, you may experience some unwanted side effects like gastrointestinal issues. 

For some populations, the combination of creatine and caffeine could be dangerous. One study found that in patients with Parkinson’s disease, combining a high intake of caffeine with creatine was linked to a faster progression of the condition.

Caffeine has some diuretic effects. Moderate intake, or between two and four cups of coffee, typically does not have a significant impact on your hydration. However, having more than five cups in a day could put you at risk of dehydration. Because creatine pulls water into your muscle cells, taking it without proper fluid intake could put you at risk of dehydration.

Certain pre-workouts

Many pre-workout mixes have creatine alongside stimulants like caffeine. Check the label on your pre-workout supplement. If there is a significant amount of caffeine or multiple active compounds, combining it with additional creatine could lead to GI distress. This isn’t inherently an issue with creatine alone, but rather with stacking too many ingredients at once.

High-dose protein supplements

For most people, combining protein with creatine is generally safe and a common practice.

However, if you take large amounts of protein supplements alongside more than the recommended amount of creatine, you could experience dehydration and GI issues like an upset stomach. Additionally, both creatine and protein can affect kidney-related lab markers, which should be monitored if you have a history of kidney problems. Talk to your healthcare provider if you’re taking high-dose protein or performance supplements with creatine.

Symptoms of an interaction

For many people, experiencing adverse side effects of creatine often stems from being poorly hydrated, taking a high dose, or stacking it with too many stimulants or other supplements. 

If you have recently taken creatine and experience the following, it could indicate a bad interaction. Some mild symptoms of an interaction with creatine include:

• GI distress, such as nausea, bloating, diarrhea, and stomach cramps
• Dehydration symptoms like dry mouth, dizziness, headaches, or muscle cramps
• Unusual fatigue or sluggishness

There are some red flags to look for; if you experience these, get medical attention immediately:

• Persistent vomiting
• Swelling in your legs and feet
• Back pain near the kidneys

How to safely integrate creatine into your routine

“If you’re going to start taking creatine, I recommend keeping it simple,” says Kitchens. She offers the following advice:

• Start with just three to five grams of creatine monohydrate daily instead of larger doses. 
• Look for a supplement that is third-party tested and lacks additional ingredients.
• Take creatine consistently, which matters more than when you take it. If you’re looking for body composition benefits, taking it post-workout might be best according to the research. 
• Drink plenty of water, since creatine draws fluid into your muscles.

Talk to your provider about getting lab work done prior to starting creatine. If you’re generally healthy, you may not need blood work. However, if you have a history of kidney issues or take medications that affect the kidneys, or if you have another health condition, it could help ensure creatine is safe for you.