Having found that her hair was starting to thin in her forties, Dr Sarah Brewer turned to a caffeine shampoo to see if it could make a difference. The results came as a pleasant surprise

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I started noticing hair thinning in my mid-40s, so that my scalp was visible through my hair at the front, and my side panels were thinner than normal. Hair is a good indicator of general health and is often the first part of the body to show signs of nutritional deficiency or ill health.

Thinning hair is almost inevitable in later life. After the age of 25, the diameter of individual hairs naturally starts to decrease, especially in women. This changes the texture and body of your hair so that, by the age of 40, most people have finer hair with less body. At the same time, more follicles stay in their resting phase (in which the hair follicle shrinks and the bulb pulls away from the root) so less hair grows and the rate of growth decreases, resulting in progressive thinning. The degree to which this occurs is often hereditary but diet and lifestyle can also play a part such as a deficiency in iron (which can put women at risk of deficiency-associated anaemia and hair loss) and iodine which could affect thyroid function with knock-on effects for hair. An excess in salt has also been linked to a reduction in the function of the hair follicle. In fact, researchers have found that cutting salt intake can lessen hair loss by as much as 60 per cent.

As I followed a reasonably healthy diet, took a good multivitamin and love a good rib-eye steak, I knew I was unlikely to have iron deficiency and I ruled out an underactive thyroid and so reluctantly concluded that pre-menopausal hormone changes were to blame.

I’ve spoken to many women about the effects of hair loss – having a ‘bad hair day’ every day has a tremendous effect on your confidence and self-esteem. I’ve seen women spray their scalp with colourants to hide thinning, use elaborate hair pieces or scarves or even become reclusive because of their hair loss.

My friend Lucinda Ellery  who is a magician with covering hair loss, covered the thinning areas with incredibly realistic fine hair extensions ( Medi Connections ). Lucinda also recommends massaging the scalp regularly with your fingers, at least once a week, and preferably every day, to stimulate circulation and increase the flow of nutrients to hair follicles.

Once I moved away from London to the Channel Islands, it was difficult to keep the hair appointments up. That’s when I discovered caffeinated shampoos and investigated the research behind Dr Wolf’s Plantur 39 shampoo and conditioner  for thinning hair.

How does it work?

When applied directly to the scalp, caffeine penetrates into your hair follicles to stimulate hair growth in two main ways: firstly, caffeine relaxes smooth muscle fibres surrounding the hair follicles to reduce scalp tension and improve circulation to deliver more oxygen, vitamins, minerals and protein for optimal hair growth. Most importantly, topical caffeine inhibits an enzyme called 5-α-reductase, which converts testosterone into dihydrotestosterone (DHT) within scalp hair follicles. It’s DHT which switches off scalp follicles and leads to thinning hair in both men and older women.

How do you use it?

The caffeine needs to be in contact with hair follicles for at least 2 minutes so it penetrates deeply and remains for up to 48 hours, even after hair washing. Drinking caffeine doesn’t work – it has to be applied externally to sink directly into scalp follicles. The easy way to do this is to apply the shampoo , £9.75, as soon as you get in the shower, then wash everything else before rinsing it off and applying the conditioner , £7.65. There is also a leave-on scalp solution , £10.49, that can be applied between shampoos and has been shown to increase the cross-sectional area of scalp hairs by 10%.

The verdict?

I wasn’t expecting miracles, but after a couple of months I suddenly realised my hair side panels had filled out and grown longer, and that my scalp was almost back to normal at the front. I’ve been using caffeine shampoo and conditioner now for at least 5 years and would not switch to anything else. In addition to a good diet that’s rich in iron and iodine and low in salt, using a caffeinated shampoo is one of the best preventative strategies for women in their 40s in my experience.

Shop the Plantur 39 range at  boots.com .  

Dr Sarah Brewer  is a GP and a Medical Nutritionist & Consultant Medical Director for Healthspan. She qualified from Cambridge University with degrees in Natural Sciences, Medicine and Surgery. She is also author of around 60 books such as ‘Eat Well, Stay Well.’