Why is my Hair Thinning? The Nutrition and Hormone Connection
Hair thinning is a common concern for women as they move through their mid-30s and beyond. While some degree of change in hair texture and density can occur naturally with age, noticeable shedding, widening of the hair part, reduced volume or brittle hair may point to underlying nutritional, hormonal or lifestyle factors that need attention.
The good news? Hair health is closely linked to overall wellbeing. Supporting the body with adequate nutrition, stress management, hormone balance and appropriate medical investigation may help improve hair quality and reduce ongoing thinning over time.
Why does hair change as we age?
Hair growth occurs in cycles, and many internal factors can influence how long hair remains in the active growth phase. As women age, hormonal changes, stress, nutrient depletion, thyroid dysfunction, digestive issues and inflammation may all impact the health of the hair follicle.
Common contributors to thinning hair in women include:
Iron and other nutrient deficiencies
Low protein intake
Chronic stress (elevated cortisol)
Thyroid dysfunction
Hormonal fluctuations of postpartum and perimenopause
Poor gut health or nutrient absorption
Rapid weight loss or restrictive dieting
Postpartum nutrient depletion
Insulin resistance or elevated androgens
Because hair is not considered essential for survival, the body often redirects nutrients elsewhere during times of stress or deficiency, meaning the hair may become one of the first areas to reflect internal imbalance.
Key nutrients that influence hair health
Protein
Hair is primarily made from a protein called keratin, meaning adequate protein intake is essential for growth and repair. Low protein diets may contribute to increased shedding, slower growth and fragile hair strands.
Including quality protein sources regularly throughout the day may help support healthy hair structure.
Food sources include:
Eggs
Fish
Chicken and red meat
Greek yoghurt
Tofu and tempeh
Legumes
Nuts and seeds
Iron
Iron deficiency is one of the most common nutritional contributors to hair thinning in women, particularly during reproductive years and perimenopause.
Low iron stores may reduce oxygen delivery to the hair follicle, affecting growth and increasing shedding. Testing iron levels may be necessary, however keep in mind that some women may experience symptoms even when iron levels sit within the ‘normal’ laboratory range - aiming for optimal levels rather than adequate may be more appropriate.
Signs of low iron may include:
Fatigue
Dizziness
Cold hands and feet
Pale skin
Breathlessness
Hair shedding
Iron-rich foods include:
Red meat
Lentils and legumes
Leafy greens
Pumpkin seeds
Sardines
Vitamin C-rich foods such as kiwi fruit, capsicum, broccoli and citrus fruit helps enhance iron absorption from meals, especially from plant-based iron sources.
Zinc
Zinc plays a role in tissue repair, hormone regulation and hair follicle function. Inadequate zinc intake may contribute to hair shedding, poor scalp health and slower growth.
Food sources include:
Oysters
Beef
Pumpkin seeds
Chickpeas
Cashew nuts
Omega-3 Fats
Omega-3 fatty acids help support scalp health, inflammation regulation and skin barrier integrity. Low intake may contribute to dryness and dullness of the hair and scalp.
Sources include:
Small oily fish - salmon, sardines
Chia seeds
Flaxseeds
Walnuts
Biotin and other B Vitamins
B vitamins support energy production, stress resilience and cellular health. While severe biotin deficiency is uncommon, low intake or poor absorption may affect hair and nail quality in some individuals.
Rather than relying solely on supplements, focusing on a broad range of wholefoods rich in B vitamins may be more beneficial in the long term.
Vitamin D
Low vitamin D levels are increasingly associated with hair thinning and autoimmune-related hair conditions. As vitamin D also supports immune and hormonal health, adequate levels may be important for healthy hair cycling. Again, testing is recommended instead of unnecessarily self-prescribing.
Hormones and Hair Thinning
Thyroid Health
The thyroid gland plays a significant role in regulating metabolism, energy and hair growth. Both an underactive thyroid (hypothyroidism) and overactive thyroid (hyperthyroidism) may contribute to hair thinning.
Signs of thyroid dysfunction may include:
Fatigue and energy issues
Weight changes
Constipation (or diarrhoea)
Dry skin
Anxiety or depressed mood
Feeling cold or hot
Irregular menstrual cycles
If thyroid dysfunction is suspected, further investigation through your GP or integrative health practitioner may be necessary.
Oestrogen Changes of Perimenopause and Postpartum
During the late 30s and 40s, hormonal fluctuations associated with perimenopause may begin to influence hair density and texture.
Declining oestrogen levels can shorten the hair growth phase, while changes in androgen balance may contribute to thinning around the crown or temples.
Women may also notice:
Increased hair shedding
Dryness
More brittle hair
Slower growth
If you are postpartum, you may notice your hair thinning at 3 months post-baby. During pregnancy, oestrogen levels remain high and the normal daily hair shedding reduces, leaving a thicker than usual head of hair. After giving birth, oestrogen drops which usually follows with hair thinning, peaking at around 3 months postpartum.
This is a normal biological process, but if you are particularly worried, it might be worth seeing your healthcare provider as it could be related to thyroid dysfunction or nutritional depletion (including low iron which is common after pregnancy).
Androgens and Insulin
While thyroid and oestrogen often receive the most attention, androgens and insulin resistance also play an important role in certain types of hair thinning in women.
Androgens such as testosterone and dihydrotestosterone (DHT) are present in both men and women. In women who are genetically sensitive to androgens, even normal levels can affect hair follicles.
Insulin regulates blood sugar levels, but chronically elevated insulin (often linked to insulin resistance) can contribute to elevated androgens. This is often seen in women with insulin-resistant PCOS and may result in female pattern hair loss (which includes gradual thinning at the crown or part-line, reduced hair density, finer, shorter regrowth cycles and slower recovery after shedding) and may be influenced by genetics and hormonal changes during perimenopause.
High insulin levels may:
Increase androgen activity in some women
Contribute to scalp inflammation
Disrupt normal hair growth cycles
Worsen hormonal imbalance during midlife transitions
Supporting stable blood sugar through balanced meals that include protein, fibre, and healthy fats may help improve insulin resistance, and in doing so, reduce androgens and other hormonal fluctuations that affect hair health over time.
Stress Hormones and the Nervous System
Chronic stress can impact hair through increased cortisol levels and nervous system dysregulation. Periods of emotional stress, burnout, illness or sleep disruption may trigger a condition called telogen effluvium (a temporary form of hair loss), where more hairs shift into the shedding phase.
This is a delayed process, often occurring 2-3 months after a stressful event and may improve once the body feels safer and more supported.
Supporting nervous system health through adequate nourishment, sleep, rest, movement, creativity, social connection and stress management can be an important part of a holistic hair health approach.
Testing That Could Be Considered
If hair thinning is ongoing or significant, pathology testing may help identify underlying contributors. Testing should always be discussed with a qualified healthcare practitioner who can interpret results within the context of symptoms and health history.
Depending on the individual, investigations that may be considered include:
Full blood count
Iron studies and ferritin
Vitamin D
Vitamin B12 and folate
Zinc
Thyroid function tests (TSH, free T4, free T3)
Thyroid antibodies
Sex hormones
Fasting blood glucose and insulin markers
Inflammatory markers
In some cases, digestive health, nutrient absorption or autoimmune factors may also warrant further exploration.
A Holistic Approach to Hair Health
While supplements and hair products are often marketed as quick fixes, they are usually not addressing the root cause of hair thinning, as healthy hair growth tends to reflect overall internal wellbeing rather than a single nutrient alone.
A more sustainable approach may involve:
Eating enough nourishing wholefoods consistently
Prioritising protein intake
Maintaining iron status
Supporting blood sugar balance
Managing stress and nervous system load
Improving sleep quality
Supporting hormonal and thyroid health
Addressing gut health and absorption concerns
Hair growth is slow, and meaningful improvements can take several months to notice. Small, consistent habits that support the body as a whole will build the strongest foundation for healthier hair over time.
Final Thoughts
Thinning hair in women over 35 years is incredibly common, but it should not always be dismissed as ‘just ageing’. Nutrient deficiencies, hormonal changes, thyroid dysfunction, stress and lifestyle factors may all contribute to changes in hair quality and growth.
By taking a holistic view of health - including nutrition, hormones, mental wellbeing and lifestyle - it may be possible to better understand what your body is trying to communicate, and support healthier hair from the inside out.
Looking for further support?
If you would like additional support on your health and nutrition journey, email me at georgie@blossominghealthnutrition.com or book a complimentary 10-15 minute discovery call or consultation through my services page here.
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