New male contraceptive – NES/T

You may not have heard but there is a new male contraceptive (NES/T) in trials at the moment.

It is getting a lot of coverage recently as a male contraceptive similar to the pill in women.

Women around the world are rejoicing at the idea of a contraceptive that men will be solely responsible for and that won’t rely on women taking all of the hormones.

So how does this miracle contraceptive work?

By reducing your natural testosterone levels!

Yes, this new male contraceptive know as ‘NES/T’ suppresses the natural production of sperm in the testes using a combination of progesterone and testosterone.

This may sound familiar if you know much about testosterone replacement therapy which can also suppress fertility in men.

How does this new male contraceptive reduce sperm production (and testosterone)? 

Sperm is produced in the testes partly due to the presence of intra-testicular testosterone. 

Testosterone is a hormone or chemical messenger produced mainly by the testes in men and in smaller amounts in women. It is considered a sex hormone due to its effects on the sex organs and production of male characteristics and behaviours. It has effects throughout the body, affecting the body, the mind, behaviour, fertility and development. It is extremely important for male well-being and physical health.

NES/T, the new male contraceptive, works in two ways. It contains progesterone (similar to some forms of the female pill) which suppresses the production of LH (luteinising hormone) and FSH (follicle stimulating hormone) in the pituitary gland.

These two hormones are responsible for the stimulation of the testes to produce testosterone and therefore sperm.

To combat the lack of testosterone produced, the new male contraceptive NES/T also contains testosterone which further suppresses the production of LH, FSH and natural testosterone through a feedback loop in the pituitary.

The pituitary senses there is enough testosterone in the blood and limits production of the two hormones which stimulate testosterone production in the testes. This also means that there is some testosterone available in the body. 

What are the issues with this new male contraceptive?

There are a few clear issues with this new male contraceptive.

Low testosterone

The new male contraceptive NES/T comes in a gel form, in a similar way to testogel.

Sounds good so far, but how do they know what dose to use? Will there be enough testosterone for every man who uses it to feel normal?

Testosterone replacement therapy is individual and should be tailored to the man. If this is being sold as a contraceptive over the counter then who is going to monitor testosterone and other hormone levels?


We know that a lot of men who take exogenous (from outside of the body) testosterone develop high oestrogen levels. Again if levels aren’t being monitored then who knows what level this will be at?

Even in the trials for this new male contraceptive medicine, they aren’t even monitoring oestrogen! Any doctor working with hormones should know that oestrogen is extremely important in men, particularly those taking exogenous testosterone.

Oestrogen is extremely important to the healthy function of men. It is mainly produced in men by conversion of testosterone into oestrogen. If testosterone levels are raised, as in men who take the gels without monitoring levels, then oestrogen will also be too high.

This can cause low mood, erratic emotions, swelling, high blood pressure, erectile dysfunction, low libido, prostate issues and cardiac problems.

Pregnenolone and other hormonal pathways

Pregnenolone is sometimes called ‘the mother of all hormones’.

It is also, as with testosterone, produced in the Leydig cells in the testes when LH is present.

When LH is suppressed, as by the new male contraceptive NES/T, pregnenolone is also not produced.

Pregnenolone has important roles in protecting brain cells and preventing Alzheimer’s related structural changes in the brain as well as being implicated in reducing memory loss in old age and improving well-being through its calming, anti-stress effects.

This is why HCG (chemically the same as LH) is often an important adjunct to TRT to improve mood and overall well-being.


Suppression and returning to normal hormone levels/fertility.

Suppressing a man’s natural testosterone production and fertility is not something to be messed around with.

In men, when these are suppressed the testicles shrink and can potentially become inactive. There isn’t good enough research yet to indicate that testosterone production and fertility will always return to normal if left for too long without HCG being used alongside it.

The NHS in the UK also don’t routinely provide HCG to men – this would lead to lots of men potentially being infertile for life after using this new male contraceptive. 

We see lots of men in our clinic who have used steroids and now have reduced testosterone production and fertility – this may have a very similar effect.


 Hormones are complicated. At OptiMale we know all too well about some of the permanent effects caused by young men dabbling with anabolic steroids.

It is very unlikely that this new male contraceptive NES/T won’t have any negative side effects. However, there is a push from some parts of society to authorise these medications for men. Mainly due to the fact that they view contraception as being a burden primarily on women.

Whilst it may be the case that a lot of women do not respond well to hormonal contraceptives, this is certainly not a reason for a tit-for-tat response which may further affect diminishing fertility rates in men.


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