I’m curious what other’s experience with Testosterone levels have been with fasting.
Here’s my experiment/experience:
The past 5 months I’ve conducted a pretty extreme experiment around fasting. I drew blood work early and after an extended experiment: I did weekly 36+ hour fasts. So I skipped about 25 days of eating since August.
For reference I am currently a 205 lbs Male, 46 years old, 17% body fat
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TESTOSTERONE
1 Month in, it was the highest my testosterone levels had ever been (911 – like a Porsche!) Historically I have averaged 740. After the 5th month it was my lowest (517). Some sort of major crash after the peak. I was really disappointed because I feel great. I was expecting an all-time high. It felt like I studied really hard for a Spanish test, but it was being graded in French.
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Other markers:
BODY FAT
About 3 months in my body fat had dropped -15 lbs, and by the end it had returned to -7lbs. Part of this was vacation, drinking, and holiday feasting. But it’s not a panacea for weight loss. Or if it is, it has diminishing returns.
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CORTISOL
Cortisol has increased. I think this makes sense as I am stressing my body weekly.
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CHOLESTEROL
Total cholesterol has increased throughout this experience. LDL and HDL both increased. There’s a lot of controversy on this as people on ketogenic diets tend to have high cholesterol. But overall this approach doesn’t seem good for those seeking to lower these levels.
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MUSCLE/STRENGTH
I gained several pounds of muscle. Unfortunately I don’t have an exact metric, but I’d estimate between 3-4 lbs. This was from an improvement in my weight training program — but I did want to point out that this method didn’t result in muscle atrophy.
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Synopsis: I’m still an advocate for it, but as with all things in life, moderation is key.
It’s my understanding that when you’ve got excess body fat to lose, fasting will increase testosterone. Because pretty much any loss of excess bodyfat will. But as you approach a more stable/lean weight, fasting will lower it.
There are a lot other factors that go into being healthful and feeling good than just high testosterone, and 517 is still a healthy level.
Also, it’s my understanding that the amount of “free testosterone” that circulates your system for availability is what really matters in terms of mood and performance. A high overall base with lower free testosterone, is worse than a much lower one with a higher free testosterone level. But getting tests for “free testosterone” levels seems to be a niche thing that’s not as easily/cheaply available. There are expensive personal data tracking programs that do it, but your average bloodwork lab doesn’t seem to offer it. Going to ask my doctor if they have any options for it on my next visit.
Thanks for sharing your input, I’m 40 year old male doing similar. Got blood work in done last month showing my levels at 722. Going to check again in March after 3 months of exercise and fasting to see how it’s changed. Started at about 50lbs overweight, so hopefully it will have improved with lower bodyfat.
What were you eating during refeeds? You need more nutrients doing fasts, it’s highly possible you weren’t getting enough choline or zinc ( which is extremely important for test ) or how was your fat intake, high levels of fat increase testosterone, and another factor is excersize, resistance training is crucial to test.
I fast regularly and testosterone is hitting me like a truck 2 months on T. Not sure if they’re related but I have been fasting regularly for about a year before taking T. Maybe it set my T effects up for success, idk, but my voice is dramatically lower and I’m growing facial hair fast enough to get a 5 o clock shadow on my chin if I shave it, again 2 months on T.
I’m 24 usually in the the level of 400s these fasting days. You’d think I’m much higher looking at me. Significant muscle mass & heavy beard & insane sex drive, and far from depressed. Im quite jealous your level is twice of mine :) Do you supplement with anything?
I actually feel like ever since I started fasting, my testosterone has decreased dramatically. Increased cortisol from fasting should lower T. However, once I resume eating for a few weeks, my T level comes back higher around the 700s at the same time at 7-8 am in the morning.
Anyone worrying about T level and fasting should understand that it’s effects seem to be temporary.
Of course fasting lowers testosterone. Anyone doing an extended fast can feel their libido leaving their bodies after a few days.
Fasting is great but it would be a lie to say it can’t have some annoying side effects.
My experience has been quite different. I have been using fasting for four years. My T levels went straight down in the first eighteen months, and then leveled off right at the Mendoza line — right at 300 ng/dl for Total T. So, not low enough for TRT, and not high enough to do anything useful.