A new gel to treat the symptoms of the so-called 'male menopause' is being launched in the UK.
The gel could boost testosterone levels in some men
The gel contains testosterone and will be used in men who are shown to have deficiencies in the hormone.
Experts say treating such men is helpful, but they stress the whole concept of whether a male menopause exists at all is still hotly debated.
The makers say the gel is stronger than alternative available therapies, so smaller amounts can be used.
The hormone replacement therapy is designed to treat men with the condition hypogonadism, caused by testosterone deficiency.
Low testosterone levels are associated with symptoms such as reduced energy levels, moodiness, low libido and increased risk of osteoporosis and death.
Dr Heather Currie, a spokesperson for the Royal College of Obstetricians and Gynaecologists, said lowered hormone levels could occur in men who have had certain operations or treatments.
She said a lack of hormones could trigger a range of symptoms in both sexes - and hormone replacement therapy could potentially benefit men as well as women.
However, And Dr Currie warned that the 'male menopause' was still controversial.
She said there was debate over whether men's hormone levels declined naturally as in women, and that even they if they did, whether the decline was as sudden or as great as in women.
Dr Ian Banks, President of the Men's Health Forum, said: "In my opinion, from the evidence around now there is a good case for testosterone replacement to be used in men who have been clinically diagnosed as testosterone-deficient."
He said delivering testosterone to men had proved problematic so far - but an effective gel would potentially be very useful.
But he said more work was needed to investigate the risks involved with the treatment - for instance, testosterone can stimulate existing prostate cancers to grow - and ensure the benefits outweighed the risks.
A spokeseman for the drug manufacterer, ProStrakan, said the other gels available in the UK were only 1% testosterone while the new gel contains 2% testosterone.
He said this meant men would ony need to apply half as much of the gel which could then be asorbed more easily.
Dr Currie said using less gel would be an advantage because, "if high volumes of gel are being used it can be quite messy and difficult to absorb."