
It’s well-known that when using testosterone, you have a very high risk of becoming infertile. Thus, a lot of men that still want to have kids now avoid TRT even though they are hypogonadal and suffer as a result.
Becoming infertile from TRT is due to suppression of gonadotropins (LH and FSH) with long-acting traditional modalities of testosterone replacement therapy such as transdermal gels, intramuscular injections (with common esters like cypionate, undecanoate, propionate, etc.), and subcutaneous pellets. Suppression of LH decreases intratesticular testosterone levels which results in the suppression of spermatogenesis. If you want to learn more about suppression from injectable testosterone, topical testosterone and intranasal testosterone, check out this vid of mine.
Another way fertility can be maintained is by converting a lot of testosterone to DHT. Usually, TRT causes infertility, but only in those who don’t get a significant increase in DHT. High 5-alpha reductase activity maintains fertility (R, R).
Let me show you a great work-around
You can still be on TRT, without the suppression. What?! How is that even possible? Here’s how.
Long-acting TRT (such as the ones mentioned above) suppresses spermatogenesis. A short-acting TRT, like oral or intranasal testosterone, maintains spermatogenesis in some men (R).
So you can enjoy all the benefits of testosterone, without compromising your fertility.
Study example
In this study, researchers took 27 men who were already on long-acting TRT for at least 2 years and switched them to intranasal testosterone (R).
5 men were on transdermal gels, 20 men on intramuscular testosterone cypionate injections, and 2 men on subcutaneous pellets. The mean age of these 27 men was 39 ± 8 years.
The intranasal T (Natesto) protocol was just 11mg twice daily. If they did not achieve eugonadal levels 1 hour after administration of Natesto 1 month after initiation of treatment, the dose was increased to three times daily. Only 1/27 (3.7%) of the men required an increase to three times daily dosing.
Here’s what happened
LH and FSH
Natesto, a short-acting intranasal TRT, allows for the maintenance of FSH and LH within normal ranges in most men despite some suppression from baseline levels, thereby allowing for the maintenance of spermatogenesis, even after being completely suppressed by long-acting TRT.
Traditionally, clomiphene citrate has been used off-label for its mechanism of inhibiting estradiol (E2) negative feedback to the hypothalamus and thereby ultimately increasing LH secretion to stimulate the Leydig cells of the testicles which, in turn, increases testosterone production in a spermatogenesis preserving manner for hypogonadal men desiring to maintain fertility potential. However, clomiphene leads to an increase in E2 and a suboptimal E2 to T ratio, which can reduce libido and hamper proper erections.
This makes Natesto superior since it doesn’t increase E2 in the same way.
Estrogen
Testosterone levels were similar on long-acting forms of TRT and Natesto (761 vs 644ng/dl), however; E2 levels were significantly lower on Natesto (39.6 vs 21.5pg/ml).
This is great because the majority of men treated with clomiphene (used to promote testosterone and fertility) achieve eugonadal serum testosterone levels; however, E2 levels tend to rise, and hypogonadal symptoms improve less optimally with clomiphene than TRT, particularly libido. And it’s difficult to have babies if you have no libido.
A high E2 to T ratio blunts some of the benefits of testosterone, so a lower E2 to T ratio with Natesto is a big bonus.
Fertility
After switching from long-acting TRT to Natesto, all 27 men had resumption of spermatogenesis with a mean sperm concentration of 50.7 million/ml (considered within the fertile range). One couple achieved a pregnancy 4 months after converting to Natesto.
Conclusion
Take a look at the differences between long-acting and short-acting testosterone.

Keep in mind, these men were hypogonadal, to begin with. That’s why they started testosterone in the first place. LH being at 4.6 on Natesto shows that it’s not really causing suppression at all.
Another important thing to point out is that when on long-acting TRT, upstream hormones, like pregnenolone, progesterone and DHEA also becomes suppressed. These prohormones play an essential role in brain function, the way you feel as well as libido and general health. The fact that Natesto doesn’t suppress LH shows that pregnenolone, progesterone and DHEA will likely be normal or at least much higher compared to long-acting TRT.
In summary, hypogonadal men on long-acting TRT interested in the resumption of spermatogenesis may convert directly to Natesto, while remaining on a form of TRT and achieving lower E2 levels.
It’s all upside. No pinning or the same mess as with topical application. The intranasal application is instant and can be done anytime, anywhere. It doesn’t suppress fertility or other prohormones, so no need to come off TRT to become fertile.
It might seem like I’m selling something here, but I’m not haha. Just sharing how you can still benefit from TRT, while remaining fertile.

>1000ng/dl Testosterone: My Step-by-Step Guide on How I Do It Naturally!