A Practical Guide on How to Dilute F75 and F100 Therapeutic Milk

October 7, 2025 •

4 min read

According to UNICEF and WHO guidelines, therapeutic milks like F75 and F100 are critical for treating severe acute malnutrition in children under strict medical supervision. Knowing how to dilute F75 and F100 properly is a foundational step in administering these life-saving nutritional formulas correctly and safely within a clinical setting.

Quick Summary

This guide provides clear, step-by-step instructions for the hygienic and accurate preparation of F75 and F100 therapeutic milks using both standard sachets and scoops, based on international guidelines. The article details the specific purpose and nutritional profile of each formula, emphasizing proper technique and critical safety precautions.

Key Points

Check Product Label First: Always prioritize the specific mixing instructions on the packaging of your F75 or F100 product, as formulas and scoops vary by manufacturer and revision.
Boil and Cool Water: For safe preparation, use drinking water that has been boiled and cooled to at least 70°C to minimize contamination risk.
Full Sachet is Most Accurate: For large-batch preparation, using a full sachet with the specified amount of boiled, cooled water (typically 2 litres) is the most accurate method to prevent dilution errors.
F75 vs. F100: F75 is for the stabilization phase of treatment, while F100 is for the rehabilitation phase. Do not substitute one for the other.
Prepare Hygienically: Maintain strict hygiene, including washing hands and sterilizing equipment, as severely malnourished children are highly vulnerable to infection.
Do Not Substitute Diluted F100 for F75: Diluted F100 has a different nutritional composition (higher protein, sodium, lactose) and is not a safe alternative to F75 during stabilization.
Observe Storage and Use Guidelines: Once prepared, therapeutic milk must be used quickly (e.g., within 2 hours at room temperature) or refrigerated for a short period (e.g., 24 hours), and any leftovers discarded.

Understanding F75 and F100 in Nutritional Therapy

F75 and F100 are specially formulated therapeutic milks used for the inpatient treatment of Severe Acute Malnutrition (SAM). They are not standard infant formulas and must be used under medical supervision. The two formulas serve distinct purposes within the World Health Organization (WHO) protocol for nutritional rehabilitation.

F75 (75 kcal/100ml): Used during the initial 'stabilization' phase (Phase 1) of treatment. It provides a low-protein, low-lactose, and low-sodium diet, rich in carbohydrates. This is crucial for stabilizing a child's fragile metabolism and correcting electrolyte imbalances without overloading compromised organs.
F100 (100 kcal/100ml): Used in the 'rehabilitation' phase (Phase 2), once the child's appetite has returned and their metabolic function has stabilized. Its higher energy and protein content is designed to promote rapid catch-up weight gain.

Hygienic Preparation is Critical

Before beginning, strict hygiene protocols must be followed to prevent contamination, which can be dangerous for severely malnourished children.

Handwashing: Wash hands thoroughly with soap and water before handling any equipment or formula. If soap is not available, use hand sanitizer.
Sterilize Equipment: Use clean, sterilized equipment, including the mixing container, whisk, and measuring jug. Using boiled water to rinse equipment can help ensure sterility.
Use Safe Water: Use only safe drinking water that has been brought to a rolling boil and then left to cool for a few minutes. The water should be at a temperature of no less than 70°C for effective mixing and to minimize contamination risk, as recommended by UNICEF.

How to Dilute F75 and F100: Step-by-Step Instructions

Always refer to the specific instructions on the product packaging, as slight variations can occur between manufacturers and batch sizes. The standard method below is for a full sachet, which is the most accurate approach.

Preparation from a Full Sachet

For preparing a large batch, the most accurate and recommended method is to use a full sachet with a precise volume of water.

Boil and Cool Water: Bring 2 litres of safe water to a boil and let it cool slightly (above 70°C). Pour the water into a sterilized mixing container.
Add Powder: Slowly add the entire contents of one sachet of F75 or F100 powder to the water. Some older sources indicate adding powder to make up to 2.4 litres, but adding to a fixed volume of water is the current standard to avoid dilution errors.
Mix Thoroughly: Whisk vigorously until the powder is completely dissolved and no lumps remain. Ensure any oil is mixed in completely and does not separate.
Cool to Feeding Temperature: Allow the mixture to cool to a safe feeding temperature before administering to the patient. Prepared milk must be used within two hours if stored at room temperature, or 24 hours if refrigerated.

Preparation Using a Scoop for Smaller Quantities

When a smaller amount is needed, some manufacturers, like Nutriset and those supplying UNICEF, provide scoops. However, instructions can vary based on the specific scoop and product version.

Check the Label: Crucially, consult the product label for the correct scoop-to-water ratio. For example, an older Nutriset guideline recommends 1 level red scoop of F75 with 18ml of water, and 1 level red scoop of F100 with 14ml of water. Newer UNICEF instructions for canisters simplified this to 25ml of water per scoop for both F75 and F100. The specific scoop provided is essential.
Mix into a Paste: Add the required number of level scoops of powder to a small amount of boiled, cooled water and mix into a smooth paste to avoid lumps.
Add Remaining Water: Gradually add the rest of the required water up to the final volume, mixing constantly until fully dissolved.

Comparison of F75 and F100


Feature	F75 (Stabilization Phase)	F100 (Rehabilitation Phase)
Energy Density	75 kcal/100ml	100 kcal/100ml
Protein Content	Low (~5% of energy)	Higher (~12% of energy)
Carbohydrate Content	High (~65% of energy)	Lower (~45% of energy)
Fat Content	Moderate (~30% of energy)	Higher (~53% of energy)
Iron	Low/Absent	Present (at physiological levels)
Purpose	Stabilize metabolism, correct electrolytes, no weight gain	Promote rapid catch-up weight gain
Duration of Use	Typically 2-7 days, until appetite returns	After stabilization, continues until recovery
Initial Patient State	Extremely fragile, oedema, medical complications	Recovering appetite, metabolic function improving

Important Considerations for Therapeutic Feeding

Monitoring Progress: A child's transition from F75 to F100 is based on clinical signs, such as the return of appetite and reduction of oedema, not simply a fixed time frame.
Transition Period: A transition phase of 2-3 days is recommended when switching from F75 to F100, where the child is offered F100 at the same volume as F75. Intake can then be gradually increased.
Infants under 6 months: Special caution is required. Extra dilution of F75 may be necessary, and specific guidelines must be consulted. Diluted F100 is not a suitable substitute for F75 in this age group due to compositional differences.
No Substitution: F75 and F100 are not interchangeable. Substituting diluted F100 for F75, for instance, is discouraged by WHO due to the different nutrient profiles which can overwhelm a child's compromised system.

Conclusion

Diluting F75 and F100 with precision and according to strict hygiene standards is vital for the effective and safe treatment of severe acute malnutrition. As these therapeutic milks are designed for different phases of treatment, understanding the purpose and proper preparation for each is fundamental for healthcare workers. By adhering to the recommended guidelines, medical staff can ensure patients receive the correct nutritional support at each stage of their recovery. The latest instructions and product specifications can often be found on the manufacturer's or supplier's website, such as Nutriset or the UNICEF Supply Catalogue.

For more detailed technical guidelines, medical professionals should refer to the official World Health Organization resources on managing severe malnutrition.

Frequently Asked Questions

F75 is a lower-calorie formula (75 kcal/100ml) used during the initial stabilization phase of severe malnutrition, focusing on metabolic recovery. F100 is a higher-calorie formula (100 kcal/100ml) used during the rehabilitation phase to promote rapid catch-up weight gain.

No, diluted F100 is not a safe substitute for F75. Their nutritional compositions are fundamentally different, and the higher protein, sodium, and lactose content of diluted F100 could overwhelm a severely malnourished child's compromised system.

Only safe drinking water that has been brought to a rolling boil and then cooled to no less than 70°C should be used for reconstitution. This reduces the risk of bacterial contamination.

Once reconstituted, the therapeutic milk should ideally be used within two hours if kept at room temperature. It can be stored in a refrigerator for up to 24 hours, but leftovers in a feeding cup should always be discarded.

While local recipes can be made in emergencies, commercially prepared products are often preferred. Local recipes require precise weighing of ingredients and carry a higher risk of error and contamination, which can be dangerous for vulnerable children.

The transition from F75 to F100 is determined by clinical signs, not a fixed schedule. This typically happens when the child's appetite returns, any oedema is significantly reduced, and they have been tolerating F75 well.

Yes, some products come with scoops for smaller batches, but the scoop-to-water ratio can differ. You must always check the manufacturer's specific instructions on the product label or packaging, as ratios have been updated over time.