While it’s important to note that individual results may vary, and some remedies may have limited scientific evidence, let’s explore the mentioned approaches for preventing hair loss and regrowing hair, supported by references:

Onion juice:  rub it in the scalp in 50:50 ratio onion juice and  water for 15 to 20 minutes 

Onion juice may have potential benefits for hair growth due to its sulfur-containing compounds. These compounds may help promote hair regrowth by improving blood circulation and stimulating hair follicles.

Green tea: make the tea and rub the scalp in 50:50 ratio with water for 15 to 20 min.

Green tea contains polyphenols that have been shown to have potential hair growth-promoting properties by stimulating hair follicles and inhibiting 5-alpha reductase.

Rosemary oil: apply it in the scalp. leave it overnight and wash it in the morning.

Rosemary oil has been traditionally used for hair care. It may help improve hair growth by enhancing blood circulation to the scalp and promoting cellular proliferation.

Zinc: ( eat zinc rich food eg. red meat, egg, )

Zinc is an essential mineral that plays a role in hair growth and repair. Adequate zinc intake, either from dietary sources or supplements, may help promote hair health.

Apple cider vinegar: one third of apple cider vinegar in a liter of water. 

Although limited studies directly link apple cider vinegar to hair growth, it may help maintain a healthy scalp environment by balancing pH levels and reducing microbial overgrowth.

Protein and trace minerals: increase protein and trace minerals rich food 

A well-balanced diet that includes an adequate amount of protein and essential trace minerals (such as iron, zinc, selenium) is essential for healthy hair growth.

Cruciferous vegetables and sea kelp:  consume more 

Cruciferous vegetables and sea kelp are rich in vitamins, minerals, and antioxidants that support overall health, including hair health.

Selenium: (eat selenium rich food- brazil nuts and seafood )

Selenium is a trace mineral that may have a positive impact on hair growth and health. It contributes to the synthesis of proteins necessary for hair structure.

Vitamin D, sleep, and exercise:

Maintaining adequate vitamin D levels, getting sufficient sleep, and engaging in regular exercise are important for overall health and may indirectly support hair health.

Silica: 

Silica is a mineral involved in the formation of collagen, which is important for hair strength and elasticity. While evidence is limited, silica supplements are sometimes used for promoting hair health.

Keto and intermittent fasting:

The ketogenic diet and intermittent fasting have gained attention for various health benefits, but their direct effects on hair loss prevention are not yet fully understood.

Biotin:

Biotin, also known as vitamin B7, is often associated with promoting healthy hair, skin, and nails. While evidence is limited, biotin supplements are sometimes used for hair loss.

It’s important to note that these remedies may not work for everyone, and it’s advisable to consult with a healthcare professional before making any significant changes to your diet, lifestyle, or using supplements. They can provide personalized guidance based on your specific condition and needs.

What to avoid to prevent hair loss – 

Medications treat hair loss by blocking an enzyme (5-alpha reductase) to inhibit DHT. DHT is a  form of testosterone that can burn out hair follicles. 

Avoid fluoride from the water and sulfates from the shampoo. 

Androgenetic alopecia and DHT:

Androgenetic alopecia, commonly known as pattern hair loss, is influenced by dihydrotestosterone (DHT), a potent form of testosterone. Excess DHT can lead to the miniaturization of hair follicles, resulting in hair thinning and eventual hair loss.

Reference: Trüeb, R. M. (2018). Molecular mechanisms of androgenetic alopecia. Experimental Gerontology, 105, 33-40.

Inhibition of 5-alpha reductase:

5-alpha reductase is an enzyme responsible for converting testosterone into DHT. Inhibiting this enzyme can help reduce DHT levels and potentially mitigate hair loss. Substances such as onion juice, green tea, rosemary oil, and zinc have been suggested to possess 5-alpha reductase inhibitory properties.

It’s important to note that these remedies may not work for everyone, and it’s advisable to consult with a healthcare professional before making any significant changes to your diet, lifestyle, or using supplements. They can provide personalized guidance based on your specific condition and needs.

Fluoride and sulfates in hair loss:

Some anecdotal reports suggest that fluoride from water and sulfates from shampoos may potentially contribute to hair loss or scalp irritation in certain individuals. Using a shower head that filters out fluoride and opting for sulfate-free shampoos can be considered as a preventive measure.