The Science

The Science Behind Salt Sisters

Every ingredient in our formula is backed by published research and UK health guidelines. This page contains the sources behind every claim we make.

As seen in

Iron deficiency in women

Our claim: Low iron affects 1 in 3 women and most have no idea

Iron deficiency is the most common nutritional deficiency worldwide and disproportionately affects women. A large UK-based study published in Frontiers in Nutrition found that nearly one in three females showed signs of absolute iron deficiency, with the prevalence exceeding 35% in women aged 18–49. NICE states the prevalence of iron deficiency anaemia in adult women in the UK is around 8%, with broader iron deficiency affecting significantly more.

According to the Royal College of Pathologists, symptoms are often non-specific — fatigue, poor concentration, low mood — and are routinely attributed to the stress of daily life rather than nutritional deficiency, meaning many women go undiagnosed for years.

Iron

Fights fatigue · Supports healthy red blood cells

Iron is essential for the production of haemoglobin, the protein in red blood cells that carries oxygen around the body. Without enough iron, the body cannot produce sufficient healthy red blood cells, leading to iron deficiency anaemia. Common symptoms include persistent fatigue, lack of energy, breathlessness and poor concentration.

The NHS recommended daily intake for women aged 19–49 is 14.8mg. Women of reproductive age are at significantly higher risk of deficiency due to monthly blood loss through menstruation.

Vitamin C

Boosts iron absorption · Supports immunity

Vitamin C significantly enhances the absorption of non-haem iron — the type found in plant-based foods and supplements. Taking vitamin C alongside iron has been shown to increase absorption by up to four times. This is why we combine both in our formula. Vitamin C also contributes to normal immune system function and the reduction of tiredness and fatigue.

The NHS recommended daily intake for women is 40mg. Our formula pairs vitamin C directly with iron to maximise bioavailability.

Magnesium

Reduces tiredness · Supports muscle function · Hormonal balance

Magnesium is involved in over 300 biochemical reactions in the body. It plays a key role in energy production, muscle function, nerve health and the regulation of the body's stress response. Studies suggest that up to 50% of people may not be getting enough magnesium from their diet alone.

For women specifically, magnesium levels fall alongside oestrogen levels during perimenopause and menopause. Research shows magnesium supplements may help with anxiety, sleep problems, low mood and reduced bone density in women. The NHS recommended daily intake for women is 270mg.

Vitamin B12

Energy and brain function · Reduces fatigue

Vitamin B12 is essential for keeping the nervous system and blood cells healthy. A deficiency causes tiredness, lack of energy, breathlessness and poor concentration. According to Cambridge University Hospitals NHS, up to 6% of people under 60 in the UK have low B12 levels, rising to 20% in the over 60s.

B12 is only naturally found in animal products, meaning women following plant-based or restricted diets are particularly at risk. Our formula provides B12 in an easily absorbed liquid form.

Zinc

Immune support · Hormonal balance · Skin health

Zinc contributes to the normal function of the immune system, helps the body make new cells, and plays an important role in hormonal regulation. It is especially important during pregnancy, infancy and the teenage years. Zinc is also known to support skin health and wound healing.

The NHS recommended daily intake for women is 7mg. Our formula stays within the safe upper limit of 25mg per day as advised by the NHS.

Folate

Cell health · Essential for women of reproductive age

Folate, the natural form of vitamin B9, is essential for making and repairing DNA, producing healthy red blood cells and supporting normal cell division. It is particularly important for women of reproductive age. The NHS recommends all women who could get pregnant take a daily folic acid supplement to reduce the risk of neural tube defects.

A deficiency in folate can cause symptoms similar to B12 deficiency including fatigue, weakness and low mood. The NHS recommended daily intake for adults is 200mcg.

Potassium & Sodium

Hydration · Electrolyte balance · Nerve function

Potassium and sodium are key electrolytes that work together to maintain fluid balance in the body, support nerve and muscle function and regulate blood pressure. When dissolved in water, our formula delivers these electrolytes directly to the body — supporting proper hydration rather than simply adding water volume.

The NHS recommends adults consume 3,500mg of potassium daily. Most women do not reach this through diet alone, particularly if they are active or consume a low-vegetable diet.

Last updated March 2026 · Sources verified against NHS, NICE and peer-reviewed publications