Energy and libido after 50: a straight guide for Kiwi men

Somewhere after 50, a lot of men notice the tank doesn’t fill the way it used to. Energy dips in the afternoon, motivation softens, and libido isn’t what it was. The supplement industry has a ready answer — it’s your testosterone, and here’s a pill — and it’s usually wrong. Here’s the straight version.

I’m Dr Roderick Mulgan, an Auckland GP and the founder of Lifeguard Health. This is an honest guide to energy and libido for New Zealand men after 50: what’s really going on, why “testosterone boosters” are a poor buy, one symptom you should never ignore, and the things that genuinely help. It sits alongside our wider men’s health guide for over-45s.

The honest picture

Testosterone does decline gradually as men age — roughly 1% a year from around 30 — and that’s normal, not a disease. But here’s what the marketing skips: for most men with flagging energy or libido, testosterone isn’t the main driver. Far more often the cause is something more ordinary and, importantly, more fixable. Chasing testosterone with a supplement usually means treating the wrong thing.

The real culprits

When a man tells his GP he’s tired and flat and his sex drive has dropped, this is the list the GP is likely to want to work through:

• Sleep. Poor or broken sleep hammers energy, mood and libido — and lowers testosterone too. Snoring with daytime tiredness can be sleep apnoea, which is common in men, often undiagnosed, and very treatable.
• Alcohol. Regular drinking disrupts sleep, mood and hormones. Cutting back is one of the fastest ways to feel more like yourself.
• Weight. Carrying extra weight around the middle lowers testosterone and drags energy. Losing some weight may genuinely shift both.
• Stress and low mood. Chronic stress and depression sap drive and libido, and they’re easy to under-recognise in men.
• Undiagnosed conditions. An under-active thyroid, low B12, iron issues, or type 2 diabetes can all present as tiredness. These are exactly the treatable causes a blood test finds.

Notice that every item on that list responds to attention. That’s the good news the supplement ads leave out.

The one symptom to take seriously

There’s a specific reason not to quietly self-treat a flagging libido: new or persistent erectile difficulty can be an early warning sign of cardiovascular disease. The small blood vessels involved can be affected before the bigger ones around the heart, so erection problems sometimes show up years before a heart issue would. That’s not said to alarm you — it’s said because it’s a genuinely useful early signal, and it’s a reason to see your GP rather than order something online. A short conversation and a heart-risk check are well worth it.

Why “testosterone boosters” don’t deliver

The supplement aisle is full of products promising to restore your testosterone, energy and drive. On the current evidence, the common ingredients rarely raise testosterone in any meaningful way, and where a man genuinely does have low testosterone, that’s a medical diagnosis confirmed by blood tests and managed by a doctor — not something a supermarket supplement fixes. Spending money there is spending it on the wrong thing.

What actually lifts energy and libido

The productive move is to fix the foundations, because they move the needle far more than any pill marketed at it:

Protect your sleep — it’s the fastest win for most men, and worth investigating if snoring or daytime tiredness suggest apnoea. Train for strength a couple of times a week and stay generally active; it supports testosterone, mood and energy. Trim the waistline and go easy on alcohol — both lift energy and drive more reliably than supplements. And deal with stress and mood honestly; if low mood is part of the picture, that’s worth raising with your GP.

On nutrients, the honest framing is gap-filling, not boosting. Being short of vitamin B12 or vitamin D genuinely saps energy, and both are common shortfalls after 50 — correcting a real deficiency helps, while topping up when you’re already replete does little.  

When to see your GP

See your GP if low energy or libido is persistent, if it’s come with low mood, or if you have any erectile difficulty — particularly if it’s new. A short visit and a simple blood test can find the treatable causes (thyroid, B12, blood sugar, low mood, and genuine low testosterone) that a supplement never will. Going is sensible, not an overreaction.

Frequently asked questions

Is low energy after 50 caused by low testosterone?

Usually not. Testosterone declines slowly with age, but most low energy and libido comes from sleep problems, alcohol, weight, stress, low mood or an undiagnosed condition like low thyroid or B12. These are treatable, which is why a GP check beats guessing.

Do testosterone-boosting supplements work?

On current evidence, no — the common ingredients rarely raise testosterone meaningfully. If you genuinely have low testosterone, that's a medical diagnosis confirmed by blood tests and managed by a doctor, not something a supermarket supplement fixes.

Can supplements improve energy and libido?

Only by closing real nutritional gaps. Being low in B12 or vitamin D may sap energy, and correcting a genuine deficiency helps; topping up when you're already replete does little. The bigger gains come from sleep, exercise, weight and alcohol.

Should I worry about erectile difficulty?

It's worth a GP visit, especially if it's new or persistent, because erectile difficulty can be an early warning sign of cardiovascular disease. It's a useful signal to act on rather than something to quietly self-treat.

Written by Dr Roderick Mulgan, NZ GP and founder of Lifeguard Health. This article is general information, not medical advice. For advice about your own energy, libido or hormones, see your GP.