Do Exogenous Ketones Actually Speed Up Ketosis? Here's What Science Says

Board-Certified Internist By Vincent M. Pedre, M.D.
Board-Certified Internist
Do Exogenous Ketones Actually Speed Up Ketosis? Here's What Science Says

Ketogenic diets are popular for a reason: They get great results. After a few weeks on this plan, my patients usually feel great and lose weight. Their mental clarity improves, they lower inflammation levels, and they reduce their risk for disease.

But getting into and staying in ketosis can be hard work. Maybe high-fat foods don't work well for you. Perhaps you travel a lot or otherwise find maintaining keto difficult. Or you're an athlete who wants to eat carbs on training days. 

With a ketogenic diet, your body converts fatty acids into ketones. You're always making ketones. But when you eat a ketogenic diet—which is high-fat, moderate-protein, and low in carbohydrates—those ketones replace glucose as your body's dominant fuel source. You're literally burning fat for fuel. 

Shifting from glucose to ketones as your dominant fuel could take days or weeks, and sustaining it can be equally challenging. "Maintaining ketosis can be difficult, as consumption of even a small quantity of carbohydrates or excess protein can rapidly inhibit ketogenesis," researchers have noted. 

That's where exogenous ketones come in. These supplements promise to sidestep the tediousness of rigorously sticking with a high-fat diet. But do they work? Let's look at the science.

 What are exogenous ketones?

Exogenous ketones, so named because your body doesn't make these ketones (they come from a supplement), can potentially raise your primary ketone—called D-beta-hydroxybutyrate, mercifully shortened to BHB—without adhering to a strict keto diet. 

Supposedly, even if you consume exogenous ketones with carbohydrates, your body will preferentially use ketones first

They come in two forms: salts and esters. Salts are bound to minerals and come in a powder form that you mix with liquid. The latter form is linked to a compound called an ester and comes as a liquid.

While they differ in certain ways, both forms promise to get your body into ketosis fast—like 30 minutes fast.


Do exogenous ketones work?

Is there any truth to these quick-start ketosis products? Maybe. The truth is, we don't have a ton of studies about exogenous ketones, but the ones we do have are promising. 

One animal study found exogenous ketone drinks could raise ketone levels without restricting carbs. In the study, rats that got exogenous ketones gained significantly less weight compared with those who did not get them.

Human studies show similar results. One review of three studies that gave participants a ketone ester or salts found that both forms elevated blood ketone levels for hours. Researchers concluded that "exogenous ketone drinks are a practical, efficacious way to achieve ketosis.

Should you try exogenous ketones?

Along with these studies, you also want to consider why you might need exogenous ketones. After all, they aren't cheap, they might not work for you, and you probably don't want to swallow a nasty-tasting liquid.

Some reasons to include them in your plan might be:

  • You want to transition into ketosis more quickly and get all its benefits including weight loss.
  • You want to be in ketosis without eating the high amounts of fat a ketogenic diet requires.
  • You're an athlete and want to cycle carbohydrates on training days.

For those conditions, exogenous ketones might—might—give you a nudge for weight loss, more energy, better performance, and more. But, they aren't a free pass to gorge on pizza and ice cream while "magically" shifting your body into ketosis.


5 strategies to optimize ketosis.

Regardless of whether you use exogenous ketones, I've found these five strategies can help optimize a ketogenic diet:

1. Eat plenty of whole, anti-inflammatory foods.

When you go keto, you eliminate sugary, processed foods that create inflammation. But ketogenic diets still often contain inflammatory foods, such as conventionally raised meats and dairy. To get the full benefits of a ketogenic diet, you need plenty of anti-inflammatory foods like wild-caught seafood and green veggies. Make sure to eat meats and dairy from grass-fed animals, free of antibiotics and hormones.


2. Maintain a cyclical ketogenic diet.

Even the best-designed eating plan can create plateaus with time. Besides, sometimes you want to eat decidedly un-keto foods like sweet potatoes and quinoa. Cyclical keto can give you the best of both worlds. You eat a high-fat diet, say, four or five days a week and have some starchier carbs on the others.

3. Incorporate fasting.

Intermittent fasting is a great way to give your digestive system a break, lower inflammation, break weight-loss plateaus, maintain your ideal weight, and so much more. Once you get into ketosis and stabilize your blood sugar, you can sustain these and other benefits with fasting. To make things simple: An eight-hour daily eating window, for instance, means you're fasting 16 hours daily. You'll ideally be sleeping about half of those fasting hours.


4. Keep stellar lifestyle habits.

Speaking of sleep: How you eat matters, but so do things like quality sleep, stress management, and exercise. To get all the benefits of a ketogenic diet, you'll want to aim for eight hours of sleep nightly, find a workout routine that works for you, and incorporate things like meditation, yoga, or deep breathing to manage stress levels.

5. Mind your gut.

Too many ketogenic diets neglect gut health by reducing the emphasis on nonstarchy vegetables. Just think of the old Atkins diet, which recommended eating a steak with butter and an egg. What affects your gut affects everything: Headaches, migraines, allergies, autoimmunity, weight gain, acne, skin rashes, yeast infections, hormonal imbalances, fatigue, immune challenges, even the way you sense pain all relate to the condition and health of your gut. Even a strict keto plan allows high-fiber plant foods as well as fermented and cultured foods like sauerkraut and kimchi. These foods provide your gut the probiotics and other nutrients it needs to stay healthy. I recommend plant-based keto for better gut health.

Vincent M. Pedre, M.D.
Vincent M. Pedre, M.D.
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