Semen, Sperm and Male Fertility: What’s Normal, What Isn’t, and When to Test
Written by Marylebone Diagnostic Centre – London’s leading clinic for private semen analysis.
Over 30 semen tests performed every week.
Semen and sperm are essential parts of male fertility, yet many people feel unsure about what is normal, what is not, and when a test is needed.
At Marylebone Diagnostic Centre (MDC), we help men understand their reproductive health through private semen analysis, advanced sperm DNA testing, and male hormone profiling.
We perform more than 30 semen tests every week, which gives us a strong understanding of the questions men ask and the concerns they often face.
This guide answers the most common searches in the UK, including:
- What is semen?
- What does sperm do?
- Can pre-sperm cause pregnancy?
- What does semen taste like?
- Is semen good for your skin?
- What causes blood in semen?
- How much protein is in semen?
- How do I improve sperm quality?
- Do I need a sperm test?
It also explains how to book a private semen analysis in London with fast, discreet results.
What Is Semen?
Semen is the whitish fluid released during ejaculation. It is made of:
- Sperm cells
- Seminal fluid (from the seminal vesicles)
- Prostate fluid
- Enzymes, vitamins and minerals
Semen provides protection and nourishment to sperm.
Why people confuse semen, sperm, semen retention and “seaman/semen”
Search engines show many misspellings, including:
- semens
- seman
- seamen (a sailor, not a biological term)
This confusion is normal.
Clinically, “semen” is the correct term.
What Is Sperm?
Sperm are the microscopic cells inside semen.
They are responsible for fertilising an egg.
Key facts:
- They need a normal shape (morphology) to fertilise an egg.
- Sperm make up less than 10% of total semen volume.
- Healthy sperm should swim forward (motility).
If you want to know your sperm count, motility or shape, a semen analysis is the correct test.
What Does Normal Semen Look Like?
Normal semen:
- Is white, off-white or slightly yellow
- Thickens shortly after ejaculation
- Liquefies within 10–30 minutes
- Has a mild, chlorine-like smell
Signs semen may be abnormal:
- Red or brown colour (possible blood in semen)
- Green or yellow (possible infection)
- Very watery (possible low sperm count)
- Does not liquefy (possible prostate issue)
If you notice changes, a semen analysis and sexual health panel can help identify the cause.
Blood in Semen – Should You Worry?
Blood in semen (haematospermia) is common and often harmless.
It may be caused by:
- Prostate inflammation
- Pelvic infection
- Past injury
- Recent sexual activity
- Enlarged prostate
- Blocked ducts
It is usually temporary, but you should consider a test if:
- It lasts longer than two weeks
- You feel pain
- You have fever
- You have urinary symptoms
- You recently had unprotected sex
MDC offers semen analysis, infection screening and prostate blood tests.
Semen Myths and Viral Internet Questions
This section answers the most-searched curiosity questions in the UK.
Is semen good for your skin?
No scientific evidence supports using semen as skincare.
It does not:
- Reduce wrinkles
- Improve collagen
- Hydrate skin
Safe, medically controlled skincare is recommended instead.
How much protein is in semen?
Very little.
One teaspoon of semen contains less than 7 calories and minimal protein.
It is not a nutritional source.
What does semen taste like?
Clinically, taste varies due to:
- Diet
- Hydration
- Smoking
- Alcohol
- Infection
A sudden change can sometimes indicate infection.
Is semen retention good for you?
There is no strong medical evidence that semen retention improves hormones, strength or mood.
Avoiding ejaculation for too long may reduce sperm quality in some men.
Pre-Ejaculate (“Pre-Sperm”) and Pregnancy – The Truth
This cluster alone has more than 30,000 UK searches every month:
- can pre sperm get you pregnant
- can you get pregnant from pre sperm
- does pre sperm make you pregnant
- can pre sperm cause pregnancy
Short answer: yes, pregnancy is possible.
Pre-ejaculate may pick up sperm left in the urethra from a previous ejaculation.
The risk increases if:
- You ejaculated recently
- You did not urinate before sex
- You are close to ejaculation
Withdrawal is not a reliable method of contraception.
If pregnancy is a concern, STD tests and a male fertility check may be recommended.
What Affects Semen Quality?
Semen quality can decline due to:
- Smoking
- Alcohol
- Heat exposure
- Tight clothing
- Stress
- Poor sleep
- Past infections
- Hormone imbalance
- Age
- Long-term medication
Improving lifestyle can improve semen results.
When Should You Test Your Semen?
You should consider a semen analysis if:
- You are trying to conceive
- Your partner had a miscarriage
- You want a fertility check
- You have low libido or erection changes
- You want to understand your hormone levels
- You have concerns about sperm count or quality
- You want a post-vasectomy clearance
MDC performs same-day semen analysis in central London.
Types of Male Fertility Testing at MDC
Semen Analysis
Checks sperm count, motility, morphology, volume and other essential markers.
Sperm DNA Fragmentation
Recommended for:
- IVF/ICSI
- Recurrent miscarriage
- Low morphology
- Unexplained infertility
Male Hormone Panel
Includes:
- Testosterone
- LH
- FSH
- Prolactin
- SHBG
Infection / Semen Culture
Identifies whether infection is affecting sperm.
Comprehensive Male Fertility MOT
A full assessment for men planning pregnancy or seeking reassurance.
Why Choose Marylebone Diagnostic Centre?
- Over 30 semen tests every week
More experience than most clinics in London. - Same day results
Fast and accurate. - Discreet private rooms
No waiting or shared spaces. - Full clinical explanation
Understand what every number means. - Advanced testing
DNA fragmentation, hormone profiles, infection testing. - 5 minutes from Baker Street station
Easy access to Marylebone, Harley Street and central London. - Trusted by London fertility specialists
Frequently Asked Questions
Book Your Private Semen Analysis Today
Get clarity. Get reassurance.
Book your private semen analysis or fertility test today at Marylebone Diagnostic Centre, one of London’s busiest male fertility testing clinics.
Quick Links
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