My Latest Testosterone Results
- © Nils Osmar 2025. October 20, 2025
- This post is not intended as, and should not be taken as, medical advice.
- See full Medical Disclaimer
Men’s testosterone tend levels to drop as we age. I’m 72 years old. My levels dropped into the low 300s about 20 years ago when I was eating a vegan diet, but they rose again when I added eggs, fish, meat, and some dairy back into my diet. I get my levels. tested every couple of months, using a blood test that I purchase through lifeextension.com. The test itself is done through a local Labcorp.
The good news:
The good news is that my total testosterone level is staying high; my most recent three readings were:
- 722 ng/dL
- 816 ng/dL
- 758 ng/dL
My estradiol levels, which were elevated when I was taking too high of a dose of DHEA, were in the low end of the reference range, which was also good news.
On the other hand…
My free testosterone is low.
Measuring free testosterone can be challenging and the results can be difficult to understand because laboratories use different assay methods, calculatory frameworks, and reference ranges. The readings can be influenced by factors such as age, sex, and even time of day; both our testosterone and free T levels run higher in the morning and drop as the day goes on. Also, most publicly available. tests do not measure free testosterone directly; they calculate it indirectly using total testosterone in relation to Sex Hormone-Binding Globulin (SHBG), and albumin. And the results and reference ranges vary between labs.
When evaluating free testosterone test results, it’s important to make sure we’re using the same test and lab consistently, because of the variation between laboratories and each labs different assessment in terms of what is considered normal, or low, or high free testosterone.
My free testosterone results
My free testosterone levels, which began sinking about a year ago, have remained low. The most recent three test results were:
- 6.8 pg/mL
- 9.3 pg/mL
- 7.0 pg/mL
A year ago, my free testosterone was 11.5 pg/mL, roughly in the middle of the reference range, so my latest readings are quite a drop. The reference range for the test I obtained through Labcorp, is 6.6-18 pg/mL.
Why my total testosterone is high:
As they mentioned above, my total testosterone levels have varied over the years; there was a time when I was avoiding animal-based food of all kinds; my testosterone levels dropped precipitously during that period.
My diet these days is not carnivore, but it is animal based. I eat lots of fish, eggs, poultry, dairy, and some red meat. I also eat foods like blueberries, and will sometimes eat white rice and other carbs. When I eat a largely animal based diet, my testosterone that tends to run higher. I don’t know if this is because of a universal principal, or just my experience. If you’re as slow, you might want to try going carnivore for a few months, or just adding more animal based foods back into your diet.
Another factor, maybe that in more recent years I’ve started taking DHEA and pregenolone, both of which are testosterone precursor. I don’t take them on the day of my blood draw, but I usually take them three or four days a week. I started doing so about 10 years ago.
What this means…
… is that my total testosterone is fine — actually high for my age — but my free testosterone levels are just barely within the reference range; if they dropped much further, they would be out of range. My goal is to. increase my free T to around where it was a year ago.
Raising my free Test testosterone: things I’ve tried
I’ve tried taking numerous things to see if I can raise my free to testerone levels, including taking including adding boron and DIM to my supplement stack. They have not had much effect yet on my free testosterone levels.. I plan to keep taking them, but I’ll moving into some additional interventions, including…
Red light therapy
After getting my most recent lab results, I started doing daily exposure of my testicles to red light in two frequencies, for 15 minutes at a time, once or twice a day for a total of about 30 minutes. The light I’m using is an LED light that does not generate heat, and has two frequencies:
- 660 nm (nanometers)
- 850 nm (nanometers)
Will this help?
I don’t know yet; I’ll report back in a couple of months about whether it makes a difference. I I don’t know if it will. At the risk of confusing the results, I will also be adding some Tongkat Ali back into my stack; I had been taking it up until a few months ago, but did not re-order it when it ran out; I just bought some and will be adding it back in.
Increased libido
As I mentioned above, I don’t know whether the red light exposure is in increasing my free tea levels; I’ve only done it twice, and they were both after my most recent blood draws. I can, however, definitely report that the red light makes a difference in my sexual arousal, which skyrockets, I literally feel, in that respect, like I’m 18 years old again after lying down for about 20 minutes with red light shining on my genitals. So I suspect it’s having an effect on my Leydig cells and is likely also increasing my testosterone levels. Whether it is increasing my free testosterone, time will tell.
“Just Ask Claude”
Regarding the increase in libido after red light exposure, I knew there was a connection, but I was not sure of the mechanism. I asked. Claude.AI whether to boost some men experience. might be related to red light’s effects on Leydig Cells in the testicles. Claude did a quick web search, then wrote.
Red light therapy does have a direct effect on Leydig cells, and this very likely accounts for much of the increased sexual arousal men report.
Our testicles contain specialized cells called Leydig cells. These are the factories where testosterone is manufactured. The process is remarkably complex, involving multiple enzymatic steps that convert cholesterol into testosterone.
Like all other processes in the body, this step-by-step conversion from one compound into another requires energy. That energy comes in the form of ATP (adenosine triphosphate), the molecular currency of cellular energy. ATP is produced primarily in the mitochondria, often called the powerhouses of the cell. Leydig cells are packed with mitochondria because testosterone production is metabolically expensive.
Why Light Might Matter
The scientific foundation for red and near-infrared light therapy is called photobiomodulation. The concept is well-established for certain applications, like wound healing and reducing inflammation.
In a nutshell:
Mitochondria contain a protein called cytochrome c oxidase, which is part of the electron transport chain that produces ATP. Red light is visible, but its effects on our metabolism do not stop at the surface of our skin. When certain wavelengths of light (particularly in the red and near-infrared spectrum) penetrate below the epidermis, into a deeper layers of tissue, they interact with cytochrome c oxidase, potentially enhancing its efficiency. The result? More ATP production.
The theory in relation to testosterone goes like this: if Leydig cells need lots of ATP to make testosterone, and red light increases ATP production in mitochondria, then shining red light on the testicles should increase testosterone production.
What the research shows:
Direct Leydig Cell Stimulation:
- Red and near-infrared light stimulate the mitochondria in Leydig cells, increasing ATP production, which enables the cells to produce testosterone at age-appropriate levels and sometimes even better than normal for one’s age The Benefits of Red Light Treatment for the Testicles – PlatinumLED Therapy Lights
- The male testes contain photoreceptive proteins called “opsin proteins” that activate with wavelengths of light, energizing the cells to enhance cellular function, including testosterone production Red Light Therapy On Testicles – Does it Boost Testosterone Production?
- Studies have reported a significant increase in testosterone production by Leydig cells in mice as a result of laser illumination with red light at 633 nm wavelength Effectiveness of low level laser therapy for treating male infertility – PMC
The Sexual Arousal Connection: The increased arousal some men experienced after red light exposure likely results from:
- Direct testosterone boost – More cellular energy in the Leydig cells triggers higher testosterone production Red Light Therapy for Testosterone Production: A Path to Better Sexual – RLT Home
- Rapid hormonal response – In a 2016 study, men receiving red light therapy saw testosterone levels grow from 2.1 ng/ml to about 3.6 ng/ml within two weeks, and reported increased libidos as well as better sexual satisfaction Red Light Therapy For Testosterone
- Multiple mechanisms – Light therapy may also interact with the pineal gland in the brain, which plays a major role in human reproduction Red Light Therapy To Increase Testosterone
Claude had these recommendations for my upcoming experiment, which are all very reasonable:
Wavelengths that work:
- 633-660 nm (red light)
- 810-850 nm (near-infrared) – penetrates deeper
Note: The device I’m using is 660nm and 850 nm, so falls into these parameters.
Important safety/effectiveness notes:
- If you are using a laser device, make sure it is not focused to a single point. Effectiveness of low level laser therapy for treating male infertility – PMC
- Sessions should be 10-20 minutes, with the device positioned 6-12 inches away from the area How to Use Red Light Therapy for Erectile Dysfunction | Blog
- Most experts recommend at least 3-5 sessions per week, though daily treatments can be more effective if tolerated well How to Use Red Light Therapy for Erectile Dysfunction | Blog
- Direct skin exposure is crucial – clothing blocks the wavelengths
Claude added a cautionary note:
One anecdotal case in the search results showed a man whose testosterone actually dropped 15% after 4 days of intense treatment. This suggests that overdoing it or improper technique might be counterproductive. The “Goldilocks zone” seems to be moderate, consistent exposure. His unexpected. results may have been related to his having had a bad cold during the experiment.
Some of Claude’s references were from websites published by companies selling red light devices, so we should take their claims with a grain of salt. It is true though that red light is has a stimulatory effect on Leydig cells, which do respond to red light stimulation and animal studies.
Not medical advice
This article is not intended as, and should not be taken as, medical advice. I’m not advising that people eat any particular diet or take any particular supplement(s), just reporting on what I’m doing. Supplements, like medications and other interventions, can have side effects; I would encourage people to research both possible benefits and side effects before starting on any supplementation regimen, and consult with a medical professional about any issues which might have a medical component. See full Medical Disclaimer
Other resources
- My Youtube channel Pathways to Longevity
- My Facebook group: Anti-Aging and Life Extension,
