Assisted fertilisation procedures rely partly on high quality sperm. It’s reasonable to assume sperm quality would be the same throughout the ejaculate. However new research suggests that this isn’t the case. Instead, it’s believed that sperm quality is higher in the first fraction of ejaculate, while remaining sperm are not as viable. What are the implications for assisted fertilisation rates following these new findings?

What Makes Up Ejaculate?

The white cloudy body fluid associated with ejaculation is made up of various secretions. These are produced by different male reproductive organs. Approximately 65% of the fluid comes for the seminal vesicles, 30-35% from the prostate, and 5% from the epididymes and testicles. There are a range of compounds found in semen including amino acids, citric acid, fructose, enzymes, potassium, zinc, prostaglandin, and phosphylcholine.

The volume of semen in ejaculation will vary from between 2 and 5ml, containing between 40 and 600 million sperm. The amount of sperm present will depend on many variables, including the length of time since the last ejaculate and the volume of ejaculate.

Read our TOP 10 tips to optimise your sperm production

The following animated video shows the functional anatomy of the male reproductive system.

Different Ejaculation Phases

There are various stages that make up ejaculation. The pre-ejaculatory phase, also referred to as pre-seminal fluid, is a colourless secretion that’s produced by the bulbourethral gland (also known as the Cowper’s gland). This fluid does not contain sperm1. The purpose of this fluid is to help lubricate the distal urethra.

The process of ejaculation occurs in two distinct phases: emission and ejaculation. During the emission sub-stage the seminal fluid gathers at the bottom of the urethral bulb in the prostate. Sperm is expelled through the vas deferens, prostate gland, and seminal vesicles. Muscular tension is increased, along with blood flow, heart rate, and breathing.

During the ejaculation phase the vesical sphincter within the bladder is closed and muscular flexes occurs within the urethra, prostate, and base of the penis. Semen is pushed outwards from the penile shaft by the perinial muscle.

How Does Sperm Quality Vary?

antioxidants protect the DNAThe recent findings of a new study led by the Ginemed Assisted Human Reproduction Clinic have provided a better insight into how sperm is distributed within ejaculate.

In this research semen samples were obtained in consecutive fraction. Each fraction was then analysed for seminal parameters, including volume, sperm motility, sperm concentration, and sperm DNA fragmentation.

The first fraction of ejaculate represents approximately 15 to 45% of the total sperm volume. Hebles and colleagues found that this portion of ejaculate contained the highest volume of sperm, they were more motile, and had the best quality DNA2.

Understanding Semen Fraction Roles

According to the researchers, this study confirms that the primary objective of the first part of the seminal fluid is to fertilise the egg. This theory is further supported by the fact that not only did the first fraction of the ejaculate hold the best quality sperm, it also contained many protective elements, such as zinc, magnesium, citric acid, and acid phosphatase.

The second half of the ejaculate makes up the remainder of the volume. Approximately 70 to 90% of this fraction is secreted from the seminal vesicles and is full of reactive oxygen species that can damage sperm. It’s thought that this serves to prevent any other males from fertilising the egg.

Implications For Assisted Fertilisation Procedures

semen sample analysis for assisted fertilisation treatments

The findings of this research may have important implications for IVF and other ARTs.

Currently semen is collected in a single container and treated as a whole.

However, since there is a clear division of function between the two fractions of ejaculate, using these phases together in IVF and other assisted fertilisation treatments may reduce the effectiveness of the procedure.

As the first fraction contains the best quality sperm and the highest concentration of sperm, it makes sense to only use this portion in assisted fertilisation treatments .

The inhibitory characteristics of the second phase of ejaculate may have a negative impact by introducing high levels of oxidative stress and potentially decreasing fertilisation potential.

Better Chances At No Extra Cost

The findings of this new study suggest that it may be easy to increase the chance of fertilisation in IVF and other assisted fertilisation procedures by separating the ejaculate phases. The good news is that this is an uncomplicated process that doesn’t require major practice changes or extra expense to implement. Perhaps the hardest part of this process will be controlling how to ejaculate in these distinct phases.

Improving Male Fertility Further With Micronutrients

Several micronutrients such as vitamins, vitaminoids, amino acids and trace elements have proven themselves effective in improving sperm quantity, mobility and shape. This directly translates into better overall sperm quality and therefore a higher chance of pregnancy.


A natural food supplementation therapy for men is

  • Relatively inexpensive
  • Effective after three to six months
  • Able to increase sperm motility by up to 23%, ejaculate volume by up to 33% and sperm count by up to 215%3
  • Without side effects

For those reasons, male fertility food supplements are most definitely recommended as the first step in the treatment of oligospermia and asthenospermia.

Pregnancy test - happy surprised womanAlso men who have not yet taken a semen analysis test will benefit from supplementing micronutrients to ensure they are able to deliver high-quality semen. There are no contraindications or side effects to this form of natural ‘sperm boosting’.

An excellent and detailed overview of many studies can be found in Steven Sinclair’s Male Infertility: Nutritional and Environmental Considerations.

A considerable range of male fertility supplements available on the UK market. The products differ widely in price and composition. has compared 10 of them in terms of value for money and the nutrients they provide.

Click the button to read a comparison of the best male fertility supplements


The Most Effective Male Fertility Nutrients

A multitude of studies has shown that highly dosed nutrients have potentially significant impact on overall sperm quality.

The amino acid L-arginine has been proven to increase sperm count and motility 4 5.

Another amino acid L-carnitine has been found to significantly improve sperm concentration (count) and motility over a relatively short period of only 8 weeks6 7.

Vitamin D has been shown to improve sperm count, motility and morphology8.

Vitamin B9, better known as folic acid has been shown to increase count, motility and morphology9.

Zinc improves the immune system and significantly improves sperm count in combination with folic acid10.

Selenium in combination with vitamin E has been found to improve motility11 12 13.


Sperm cells take 11 weeks to mature in the testicles. Only then they are ready for ejaculation.
If you adjust your diet today it will thus take three months for the better sperm to be ready for fertilisation.
You must therefore keep the diet or supplement on an ongoing basis – ideally until your partner is pregnant or you decide for a different treatment.

All of the male fertility supplements in our great test include several of these nutrients at once, albeit at a lower dose. This is a cost-effective and convenient way making this type of fertility therapy affordable and requiring taking only one all-in-one supplement instead of many. 

To find out more about the effects of the individual nutrients and how the various supplements compare, please read’s male fertility supplement review.

Click the button to read a comparison of the best male fertility supplements



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  1. “Zukerman, Z. (2003). Does preejaculatory penile secretion originating from Cowper’s gland contain sperm? Journal of Assisted Reproduction and Genetics. Volume 20, Issue 4, (pp. 157-9).”
  2. “Hebles, M. (2015). Seminal quality in the first fraction of ejaculate. Systems Biology in Reproductive Medicine. Volume 61, Issue 2, (pp. 113).”
  3. “Imhof, Martin et al., “Improvement of sperm quality after micronutritient supplementation”, e-SPEN, the European e-Journal of Clinical Nutrition and Metabolism, Epub published ahead of print.”
  4. “”
1 reply
  1. Paulo
    Paulo says:

    If his ejaculate is clear, like water, it most lilkey contains little or no sperm cells. Seminal fluid made in the prostrate gland is clear, at the moment of ejaculation it mixes with sperm cells from the testicles, it is the presence of the sperm cells that give an ejaculation it’s pearly white color.Your boy friend MAY be experiencing what is known as a “Retrograde Ejaculation”, this is when the sperm cells travel in the wrong direction, towards the bladder instead of down and out the urethra. It then mixes with his urine and is expelled at his next urination.He can find out for sure what is going on with a simple trip to the doctor.Is it possible that your boyfriend may have had a vasectomy and is not telling you about it? This too would make his ejaculate appear clear as the sperm cells are blocked from making ANY kind of exit.


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