If you are losing hair, your first instinct is probably to search for a product that will fix it. That makes sense, though products only work when the conditions inside your body allow them to. Hair loss and overall health are far more connected than most people realise. Your hair follicles need a constant supply of nutrients, energy and balanced hormones to keep growing. When something inside the body is off, hair is often one of the first things to suffer. This piece explains how diet, stress, sleep, exercise and your hormones all influence what is happening on your scalp, and what you can do about it.
Your hair is a barometer of your internal health
When the body is under pressure, whether physical or emotional, it sends resources to the organs that keep you alive first. Hair growth is not one of them. At times of stress, a greater percentage of hairs shift prematurely out of the growth phase, called anagen, into a resting phase, called telogen. Around two to three months later, those resting hairs shed. This delay is the reason you often notice the hair loss a few months after the stressful event has passed.
A 2025 systematic review of more than 61,000 people confirmed that diet, nutritional status and lifestyle have a measurable effect on hair density, thickness and shedding.
The DOSE Pillars of Health
At DOSE, we work with four foundational pillars that influence hair health. Any treatment, whether topical, oral or in-clinic, performs better when these pillars are in good shape:
- D for Diet
- O for Oneness
- S for Sleep
- E for Exercise
D | Diet and nutrition
Hair is made almost entirely of protein, and the cells that produce it are some of the fastest-growing cells in your body. That makes hair very dependent on what you eat. When the nutrients your follicles need are in short supply, growth slows, strands thin and shedding increases. These are the most common dietary factors involved in hair loss.
Iron
Iron deficiency is the most common nutritional cause of hair loss in women. It is also one of the most missed, because standard NHS blood tests do not always check ferritin, the body's iron storage protein. If your iron stores are low, your follicles cannot keep up with normal growth. Ask your GP to specifically include ferritin in any blood test. Restoring iron stores typically takes several months.
Vitamin D
Vitamin D plays a direct role in how your hair follicles cycle. A 2024 meta-analysis found vitamin D deficiency in more than half of patients with female pattern hair loss, telogen effluvium and alopecia areata. In the UK, deficiency is common, particularly between October and March when sunlight is limited. A daily supplement through the darker months is a sensible baseline.
Protein, zinc and B12
Hair is keratin, which is a type of protein. If you are not eating enough protein, your body has nothing to build new hair with. Zinc and B12 also support healthy growth, and deficiencies in either can show up in your hair before anywhere else.
Crash diets and rapid weight loss
Restrictive eating, very low-calorie diets and rapid weight loss are some of the most common triggers for shedding. Your body interprets sudden food restriction as a stressor and pauses non-essential functions, hair included. Sustainable, balanced eating supports your hair far better than any short-term restrictive plan.
O | Oneness
Stress sets off a chain reaction in your body that releases cortisol, the main stress hormone. When cortisol stays elevated for weeks or months, the hair follicle stays in its resting phase for longer. It also triggers the release of a small protein called substance P, which activates immune cells in the scalp. These cells release inflammatory chemicals into the tissue around the follicle, which further disrupts normal growth.
A 2024 study of 120 patients with androgenetic alopecia found that those under psychological stress had consistently higher cortisol levels and their hair loss continued to progress despite being on treatment.
There is also a feedback loop to watch for. Hair loss causes anxiety, anxiety raises cortisol, and cortisol worsens hair loss. Breaking this loop matters as much as any treatment. Evidence-based ways to lower stress include:
- Mindfulness practice and meditation, even ten minutes a day
- Breathwork, particularly slow nasal breathing or box breathing
- Regular time in nature
- Talking to someone who understands, whether a friend, therapist or support community
These are practical interventions that lower cortisol and give your follicles a real chance to recover.
S | Sleep
Sleep is when your body does most of its repair work, including for your hair. During deep sleep, you produce growth hormone which acts directly on your hair follicles and help extend the growth phase.
A 2025 systematic review of 29 studies found that poor sleep was significantly more common in patients with alopecia areata, androgenetic alopecia and telogen effluvium than in healthy people. Consistently sleeping less than six hours a night is linked to a higher risk of hair shedding.
Aim for seven to nine hours of quality sleep. Not eating too close to bed time, going to sleep at the same time every night, a dark room, and a screen-free wind-down all help.
E | Exercise
Exercise supports your hair health in several ways at once. When you move, your heart rate climbs and circulation improves, which means more oxygen and nutrients reach your scalp and follicles. Exercise also helps lower cortisol, regulate insulin and support the hormones that influence the hair cycle.
The mental health benefit is just as important. Regular movement is one of the most reliable ways to lift your mood, reduce anxiety and improve your overall sense of wellbeing. Since stress and anxiety feed directly into hair loss, this matters far more than people realise. A workout you enjoy and look forward to does double duty: it lowers your stress hormones in the moment and helps you sleep better that night.
You do not need an intense routine for any of this to work. A daily walk, dance class, regular yoga, swimming or strength training a few times a week is enough.
One note on balance: over-training, very low body fat or extreme calorie restriction can become a stressor in itself and trigger shedding. Moderate, consistent activity supports your hair far better than punishing routines.
Other medical factors worth investigating
Several other conditions commonly drive hair loss and should be ruled out with a professional. Thyroid disorders, whether under- or overactive, frequently cause diffuse shedding, thinning and/or texture changes. Hormonal shifts during perimenopause, after pregnancy, after coming off the contraceptive pill, or with PCOS all change the hair cycle. Hair loss after illness, especially after COVID, high fevers or surgery, is well documented. Certain medications also list hair loss as a side effect. If you are unsure, see your GP or a consultant dermatologist rather than self-diagnosing.
What to do next
Here is a practical plan:
- Book a blood panel with your GP. Ask specifically for a full blood count, ferritin, vitamin D, B12, zinc, thyroid function (TSH, T3, T4), and a sex hormone profile if relevant. Many of these are not included in standard checks unless you request them.
- Audit the four pillars honestly. Where is your weakest link? Diet, sleep, stress or movement?
- Pair foundational changes with clinically proven treatments. Topical and oral hair loss treatments work best when your body has the resources to respond. Without the foundations in place, results plateau.
- Take the DOSE online consultation for dermatologist-led recommendations tailored to your specific type of hair loss.
Hair recovery is rarely fast, and it is rarely about one thing. When you treat the whole body, you give your hair the best possible chance of regrowth.
