Does Keto Increase or Lower Testosterone? | Real Answers and Science

We’ve all seen the guy at the gym–he’s bench pressing automobiles, he has hipper hair than we ever had, and he’s always telling you what to eat and what not to eat. It’s easy to brush that guy off. He’s got genetics and he’s two decades younger than us, right?

It turns out, though, that those guys might be more right than even they’re aware of. That’s because certain diets lower our blood sugar, like Keto, which in turn could help us raise our Testosterone. To examine how this process works, let’s jump into the nitty-gritty.

What You Need to Know

  • Diets like Keto can effectively lower blood sugar.
  • Lower blood sugar leads to better insulin sensitivity.
  • Blood sugar and insulin have a direct relationship with Testosterone.
  • Some studies have already shown that the Keto Diet specifically can boost Testosterone.

What is Keto?

The Ketogenic, or just Keto Diet gets its name from a biochemical process called ketosis. The principal is basic in the extreme. When our bodies run out of blood sugar (glucose) it begins to burn fat, either from our diet or from stores around our bodies. In order to encourage our bodies to reach a state of ketosis, the Keto diet severely limits the carbohydrates that we eat.

This diet is what we call hard yakka where I’m from. Real hard work. In fact, less than 5% of people can stay on it, with over a third saying it’s just too hard. But if you can stick with it, over time you’ll increase your body’s insulin sensitivity and lower your blood sugar–both great for Testosterone.

Blood Sugar, Insulin, and Testosterone

High blood sugar and low Testosterone are so correlated that even diabetes websites warn about how too much glucose can affect your hormones. Much of this comes down to something called insulin resistance.

Insulin is a hormone that our pancreas makes, and it signals our cells–from our muscles to our brains–to draw glucose out of our blood and use it as fuel. When we have too much sugar in our blood, over a long period of time, our bodies basically get numb to the insulin message: our cells stop answering the phone when it calls. As a result either our bodies stop making insulin, or it goes into overdrive and pumps out way too much.

In either case, our bodies aren’t taking up the glucose from our blood–high blood sugar–and our bodies are totally insulin resistant.

How it All Affects Testosterone

The mechanisms remain unclear for some scientists, but the correlation is like crystal. Men with higher blood sugar and higher insulin resistance have long-term lower Testosterone.

Other scientists have speculated that this direct relationship may be due to how insulin affects the actual energy maker of each cell in our body, mitochondria. In a study published in Diabetes Care, the authors found evidence that insulin was having a direct impact on our bodies ability to process Testosterone, and may be through the impact something called metabolic syndrome. This umbrella term for diseases includes our cellular inability to process calories correctly. And in their study, they found it had a direct impact on Testosterone.

Keto to the Rescue

If you haven’t made the leap yet, let’s take it together. If high blood sugar and insulin resistance kills Testosterone, and Keto lowers blood sugar and increases insulin sensitivity–then Keto should be good for Testosterone.

And we’re correct. I’ve found two separate studies that show Keto Diet improves all measures of Testosterone health in men. 

The first study was published in the Journal of Strength and Conditioning Research, and found significant Testosterone gains after only 11 weeks of Keto Diet and exercise. The next year, a new study found significant Total Testosterone gains after only 1 week. And gains continued going up through four weeks of study.

I’ve read some other speculation in the literature reviews of journals that are still speculating on the effect of the Keto Diet raising testosterone–whether it’s insulin related or something going on directly in the hypothalamic-pituitary-gonadal axis. Most evidence, as we’ve seen, points to the insulin factor, though there’s no reason at this point to discount other mechanisms.


Whatever the processes, it’s clear from both the theory and the application in studies that the Keto Diet has a huge benefit to Testosterone levels. Though like with any diet or exercise routine, you shouldn’t jump in blind. If you’re considering trying Keto out, have a chat with your GP to make sure you’re healthy enough to give it a go–because, as I’ve mentioned, it’s a hard diet to stick with.

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About the Author

Sam is a passionate health and fitness enthusiast who has been interested in supplements, fitness, and wellness for over 10 years. He is the founder of Great Green Wall - the health and wellness brand and has completed multiple fitness certificates, including personal training and nutrition certifications. Sam has been working as a personal trainer for the past three years and is dedicated to helping his clients achieve their fitness goals and lead healthier lifestyles. He believes that a healthy lifestyle is crucial to a happy and fulfilling life and is committed to sharing his knowledge and passion with others.

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