How long does breastmilk soap last?

Breastmilk soap is made from breastmilk and has become increasingly popular in recent years. But how long does it actually last before it goes bad? Here is a comprehensive look at how long breastmilk soap lasts, how to tell if it has gone bad, and how to extend its shelf life.

What is Breastmilk Soap?

Breastmilk soap is exactly what its name implies – soap made from human breastmilk. Many mothers choose to pump and donate excess breastmilk that their own babies do not consume to soapmakers. The breastmilk is then combined with other ingredients like oils, sodium hydroxide, and fragrance or essential oils to create a gentle, nourishing soap.

Advocates of breastmilk soap believe it has many benefits compared to traditional soap. The proteins, vitamins, and fatty acids naturally found in breastmilk are thought to be excellent for your skin. Breastmilk contains compounds like lauric acid and immunoglobulins that may have antimicrobial properties. The soap is also very gentle and suitable for babies, children, and adults with sensitive skin.

How is Breastmilk Soap Made?

To make breastmilk soap, the breastmilk goes through a process called saponification along with oils, sodium hydroxide lye, and other additives. Here are the basic steps:

  1. The breastmilk, oils, sodium hydroxide lye, and other ingredients are combined and mixed together.
  2. This causes a chemical reaction called saponification where the oils and sodium hydroxide lye turn into soap and glycerin.
  3. The mixture is blended to emulsification so the ingredients incorporate fully.
  4. Once the soap has thickened adequately, fragrance or essential oils are added for scent.
  5. The soap mixture is poured into molds and allowed to fully harden.
  6. Once hardened, the soap is removed from the molds and cut into bars if needed.
  7. The finished breastmilk soap bars are wrapped and packaged.

The saponification process allows the proteins, sugars, and fatty acids naturally found in breastmilk to be retained in the finished soap. This gives breastmilk soap its gentle, nourishing qualities for skin.

How Long Does Breastmilk Soap Last?

Breastmilk soap can last 1-3 years when properly stored. The shelf life depends on these factors:

  • Ingredients used – Soaps made with hard oils and butters like palm oil, coconut oil, or shea butter will last longer than those made solely with soft oils like olive oil.
  • Additives – Fragrances, essential oils, and other additives can impact shelf life. Some additives make soap go rancid faster.
  • Curing method – Fully cured and dried soap lasts longer than soap that is used immediately after making.
  • Storage method – Soap that is tightly wrapped and stored in a cool, dry place away from light and heat will have a longer shelf life.
  • Water content – Soap with lower water content tends to last longer.

Here are some general guidelines for how long well-made breastmilk soap will last:

Storage Method Shelf Life
Stored tightly wrapped in a cool, dark place 2-3 years
Stored loosely in a bathroom 6 months – 1 year

How to Tell if Breastmilk Soap Has Gone Bad

Here are some signs that your breastmilk soap has spoiled and should be discarded:

  • Change in color – Fresh breastmilk soap is off-white or lightly colored. Darkening or unnatural colors indicate spoilage.
  • Strong, rancid odor – Breastmilk soap will naturally have a mild, milky aroma. A sour, rotten, or rancid smell means it has gone bad.
  • Mold
  • Texture changes – Soap that is very soft, sticky, mushy or oozing is past its prime.
  • Cracks, crumbling, shrinkage – Signs of drying out.
  • Liquid beads of oil on the surface – Also known as “weeping” which happens when soap goes rancid.

If you notice any of these issues with your breastmilk soap, it is best to discard it and not use on your skin. Rancid soap can harbor bacteria and be irritating.

How to Make Breastmilk Soap Last Longer

Here are some tips to extend the shelf life of your breastmilk soap:

  • Cure it properly – Allow breastmilk soap to cure for 4-6 weeks before use. This evaporation process helps harden the bars.
  • Store in a cool, dark place – Keep soap in an area around 60-75°F. Avoid excess heat, humidity, and sunlight.
  • Wrap tightly – Individually wrap bars in plastic wrap or waxed paper to protect from air and moisture.
  • Use harder oils – Soaps made with more coconut, palm, or shea butter will have a longer shelf life than those made solely with soft oils.
  • Don’t rewet – Letting water pool on the soap or leaving it in the shower will shorten its lifespan.
  • Watch for signs of spoilage – Discard if you notice any changes in color, scent, texture, etc.

Storing breastmilk soap properly in a dark, dry environment is key to getting the most longevity out of it. Tightly wrapping each bar also helps prevent air exposure and lengthens the shelf life. With optimal storage conditions, most breastmilk soap will last 1-2 years before expiring.

Should Breastmilk Soap Be Refrigerated?

Refrigeration is not necessary for preserving breastmilk soap. The saponification process used to make the soap allows it to remain stable at normal room temperature. As long as the breastmilk soap is properly formulated and cured, cooling it is not needed to prolong shelf life. Simply keeping it wrapped in a relatively cool, dark place is sufficient.

Does Breastmilk Soap Expire?

Yes, breastmilk soap does have an expiration date and shelf life. The ingredients that make up the soap will eventually go rancid and degrade in quality over time. Signs that breastmilk soap has expired include:

  • Change in color or texture
  • Unusual smell – rancid, sour, or rotten odor
  • Mold growth
  • Dryness, shrinking, or cracking
  • “Weeping” or liquid beads of oil on surface

Once breastmilk soap displays any of these characteristics, it should be discarded. Using expired breastmilk soap, especially if it smells rancid or has mold, can lead to skin irritation and infections. An expired product will not have the same beneficial qualities of fresh breastmilk soap.

Can Expired Breastmilk Soap Make You Sick?

Using breastmilk soap past its prime carries some risk of skin irritation, rashes, or infection due to bacterial growth. Rancid soap contains free fatty acids that can disrupt skin cell membranes and irritate sensitive skin. If mold is present, mycotoxins can cause issues if absorbed through cracked skin. The fragrances in out-of-date soap may also trigger dermatitis in some.

Healthy, intact skin is an effective barrier against most microbes. But people with eczema, open wounds, or compromised immune function should avoid using spoiled soap due to increased infection risk. Discard expired breastmilk soap rather than chance skin reactions or bacterial infections.

How to Safely Discard Breastmilk Soap

To safely get rid of expired or unwanted breastmilk soap:

  1. Wrap the breastmilk soap securely in plastic wrap or waxed paper if not already packaged.
  2. Place the soap in a sealed bag or container so it doesn’t leak or contaminate anything.
  3. Dispose of the soap bundle in your regular household waste bin.
  4. Do not attempt to compost or recycle old breastmilk soap, as it contains ingredients that don’t break down.
  5. Wash your hands after handling discarded soap.

Breastmilk soap doesn’t require any special disposal methods. Simply contain it well and throw away as normal garbage. Never attempt to send expired breastmilk soap down the drain, as the oils and fats may clog your plumbing over time.

Is it Safe to Use Old Breastmilk for Soapmaking?

Soapmakers do not recommend using previously frozen breastmilk that is past its prime for drinking to make soap. Fresh breastmilk works best. Here’s why you should avoid using old or expired breastmilk for soap:

  • The quality and integrity of the milk declines over time.
  • Nutrients and beneficial properties are lost.
  • Can impart unpleasant odors to the finished soap.
  • May grow dangerous bacteria like staph if left for too long.
  • Difficult to determine true freshness and quality.

Frozen breastmilk maintains more nutrients compared to refrigerated. But for optimal soap nutrition and skin benefits, the highest quality option is fresh milk donated specifically for the purpose of soapmaking. Discard any leftover milk after soaping.

Does Breastmilk Soap Need to Be Refrigerated After Opening?

Refrigeration is not necessary for breastmilk soap after opening. The saponification process converts the oils and breastmilk into a stable soap product that does not require cooling. Leaving breastmilk soap in the fridge can actually accelerate sweating and mold growth.

Instead, simply rewrap your breastmilk soap tightly in its packaging to protect it from excess moisture. Keep it stored in a relatively cool, dry location away from direct light. Avoid letting it sit in standing water or get soggy between uses. With proper dry storage, opened breastmilk soap will remain fresh and usable for many months.

Can You Freeze Leftover Breastmilk Soap?

Freezing is not recommended for leftover bars of breastmilk soap. The freeze-thaw cycle can damage the texture, creating cracks, sweating, and brittleness. Instead, here are some better options for dealing with excess breastmilk soap:

  • Tightly wrap and store at room temp to save for later.
  • Gift or share with friends and family if you won’t use it fast enough.
  • Grate and melt down old soap to create a new batch.
  • Safely discard in the trash if it shows signs of mold or spoilage.

With proper storage at 60-75°F, most breastmilk soap will remain usable for 1-3 years. Try to buy or make it in quantities you can use up during this window. Freezing breastmilk soap causes more harm than good.

Frequently Asked Questions

Does breastmilk soap need to be kept in the fridge?

No, properly formulated breastmilk soap does not need to be refrigerated for preservation. The saponification process creates a stable product able to be stored at room temperature. Simply keep it tightly wrapped in a relatively cool, dark place.

Can you use breastmilk soap after the expiration date?

It’s not recommended to use breastmilk soap past its expiration date. Old, expired soap often has rancid ingredients that can irritate skin and harbor bacteria. Discard and replace any breastmilk soap that is past its prime.

What happens if breastmilk soap gets wet in the shower?

Getting the soap wet between uses can shorten its lifespan by exposing it to excess moisture. Always store breastmilk soap in a well-ventilated area out of standing water. Rewrap bars tightly after use to help prolong freshness.

Can old breastmilk still be used for soapmaking?

Soapmakers don’t advise using previously frozen or expired breastmilk to make soap. For the best nutrition and skin benefits, fresh breastmilk is optimal. Old milk may grow dangerous bacteria over time.

Does breastmilk soap attract mold easily?

If stored improperly in damp conditions, breastmilk soap can develop mold. Keep bars tightly wrapped in a dry environment. Discard any soap that shows mold growth, as the spores can trigger respiratory issues if inhaled.


With proper formulation, curing, and storage methods, most breastmilk soap has a shelf life of 1-3 years. Keep it wrapped tightly and stored in a cool, dark place to get the most longevity. Signs that breastmilk soap has expired include changes in color, scent, texture, and mold growth. Discard and replace soap that is past its prime to enjoy the benefits of fresh breastmilk soap. Following these tips will help you safely preserve and enjoy breastmilk soap.

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