Why Am I Always Tired?
What the Research Actually Says
Persistent fatigue is one of the most common health complaints in New Zealand, and one of the most complex to address. Here is a clear-eyed look at causes, solutions, and where supplements actually help.
You slept eight hours. You are not particularly stressed. You eat reasonably well. So why are you always tired?
Fatigue is one of those symptoms that resists simple explanations. It can stem from dozens of different causes, sometimes several simultaneously. The most effective approach is methodical: rule out medical causes first, then address the physiological factors you can control.
Rule Out Medical Causes First
Before looking at lifestyle or supplementation, a GP blood test is worth doing if fatigue is persistent. Key things to check:
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Iron and ferritinLow ferritin causes significant fatigue even when haemoglobin is technically normal. This is one of the most commonly missed causes, particularly in women.
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B12Deficiency causes profound fatigue and cognitive issues. Vegetarians and older adults are particularly at risk.
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Vitamin DWidespread deficiency in NZ, particularly in winter. Fatigue is one of the primary symptoms.
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Thyroid function (TSH)Underactive thyroid causes severe, persistent fatigue. A simple blood test rules it in or out.
The Cellular Energy Angle Most People Miss
Your body's primary energy currency is ATP, adenosine triphosphate. Every cell, from muscle fibres to brain neurons, runs on it. When ATP production is impaired or depleted, fatigue follows at every level, physical and cognitive simultaneously.
This is where creatine monohydrate becomes relevant. It works by increasing phosphocreatine stores, which serve as a rapid buffer to regenerate ATP. This is well-established for muscle performance, and increasingly supported for cognitive and general energy as well.
Creatine is not a stimulant. It does not contain caffeine or any energy-mimicking compound. It improves the efficiency of energy production at a cellular level, a fundamentally different and more sustainable mechanism than stimulants.
What the Research Shows on Creatine and Fatigue
Multiple studies show creatine supplementation reduces subjective fatigue, improves performance under conditions of sleep deprivation, and supports mental energy under cognitive load.
A 2024 study found participants maintained significantly better cognitive performance after taking creatine during total sleep deprivation versus placebo. For vegetarians and vegans, who have lower baseline creatine stores, the fatigue-reducing effect is particularly pronounced.
The women's health angle is also significant. Oestrogen influences creatine metabolism, which means the hormonal changes of perimenopause and menopause can directly contribute to chronic fatigue through reduced cellular energy efficiency. Creatine supplementation helps compensate for this.
Practical Steps in Priority Order
- Get a blood test to rule out iron, B12, vitamin D deficiency, and thyroid issues
- Prioritise sleep quality, consistent bedtime, dark room, no screens pre-sleep, magnesium glycinate if sleep is disrupted
- Adequate protein intake, 1.6g per kg bodyweight minimum supports stable energy
- Add 3-5g of creatine monohydrate daily to support cellular energy production
- Address chronic stress, cortisol chronically elevated depletes energy reserves and impairs sleep
- Adequate hydration, even mild dehydration impairs energy significantly
Frequently asked questions
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