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What is Colostrum? Definition + Side Effects & Dosage

Written by Aleksa Ristic, MS (Pharmacy) | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Aleksa Ristic, MS (Pharmacy) | Last updated:
Powder supplement

Colostrum or the “first milk” is rich in nutrients, growth factors, and digestive enzymes. Read on to learn what it is, how to take advantage & what the side effects are.

What is Colostrum?


Colostrum is a type of milk breastfeeding women produce just after giving birth. Aside from humans, as all breastfeeding mammals also produce this nourishing fluid. It is a diverse mix of nutrients such as carbohydrates, fats, vitamins, minerals, and more [1].

Newborns are vulnerable to diseases as their immune system is still forming. They especially benefit from the antibodies in colostrum, which boosts their immunity, aids immune development, and protects them against infection. Its composition is unique and loaded with growth factors that newborns require for muscle, bone, and cartilage growth and repair [2].

Colostrum is also known as “first milk”. It becomes “transitional milk” about 5 days after birth and “mature milk” about 2 weeks after. Mature milk is higher in fat, lactose, potassium, and calcium, while colostrum is higher in protein, sodium, chloride, and magnesium. Colostrum is also higher in growth factors such as IGF-1, IGF-2, and VEGF, and immune factors such as lactoferrin [3, 4].

Colostrum, or “first milk,” is the very first type of milk produced right after a person (or animal) gives birth. It supports the newborn’s immune system and provides a rich source of nutrients and growth factors.


Colostrum from other animals, especially from cows, is often consumed for its health benefits. Research shows that it may be helpful for a variety of issues, from enhancing exercise performance to boosting immunity and relieving “leaky gut”.

However, much less is known about its benefits in grown-ups than about its relevance for newborns. Another reason for skepticism is that many studies used a specialized type of colostrum (called hyperimmune colostrum), which is still not commercially available. The evidence to support the use of colostrum found in most supplements is less conclusive.

For more about the potential benefits of colostrum, check out this post.


Colostrum is filled with an incredible number of potentially beneficial components. The list is quite long, so bear with us… Colostrum contains all the following [1]:

Growth factors

  • Epidermal growth factor (EGF)
  • IGF-1 and IGF-2
  • TGF-Beta
  • Fibroblast growth factor 1 and 2 (FGF1 and FGF2)
  • Platelet-derived growth factor (PDGF)


  • Lactoperoxidase, an antioxidant enzyme with antibacterial properties
  • Plasmin, which removes blood clots [5]
  • Lipoprotein lipase, which breaks down fats [6]
  • Esterases, which break down drugs [7]
  • Alkaline phosphatase
  • Ribonucleases, which fight microbes and orchestrate the expression of your genetic material (helping new RNA mature and cleaning old RNA) [8, 9]
  • Lysozyme, a destroyer of bacterial cell walls
  • γ-Glutamyl transferase

Colostrum also contains:

Colostrum is rich in nutrients, growth factors, digestive enzymes, immunoglobulins, and other compounds that are important for the first few days of a newborn’s life.

Mechanisms of Action

Diverse compounds interact to achieve the overall health benefits of colostrum. To sum it up, this nutrient-dense milk:

Boosts immunity by activating natural killer cells and stimulating IFN-gamma and IL-2 release [16, 17].

Acts as an antioxidant (suppressing harmful myeloperoxidase activity) [18].

May relieve diarrhea from HIV because of its anti-inflammatory and anti-microbial properties, in addition to its ability to eliminate bacterial toxins [19].

May help overcome leaky gut and overheating from strenuous exercise (by raising heat shock protein levels and lowering Bax-alpha levels) [20].

Lactoferrin binds to NSAID painkillers, which blocks their activity and prevents stomach damage [21, 22].

May help with post-surgery recovery by repairing tissues, lowering gut inflammation, and eliminating bacteria and their toxins [19].

May be beneficial in diabetes potentially by raising IGF-1 levels, which can help the body use and store glucose more effectively [23].

Colostrinin, a protein mixture in colostrum, may help with Alzheimer’s by blocking the clustering of amyloid-beta and reducing their damage to brain cells [24, 25].

Colostrum has a complex mechanism of action because of its many active components.

Hyperimmune Colostrum

Hyperimmune colostrum is colostrum with extra antibodies toward a specific intruder, such as bacteria or viruses. It is made when vaccinations are given to pregnant cows, in response to which they produce specific additional antibodies. These antibodies get transferred to their colostrum, which may protect against specific infections in humans [26].

The FDA has approved hyperimmune colostrum for rare conditions (orphan drug status), but it is not available as a supplement, unlike regular colostrum.

Colostrum Side Effects & Precautions

This list does not cover all possible side effects. Contact your doctor or pharmacist if you notice any other side effects. In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.

According to a review of 51 studies, colostrum is generally safe and well-tolerated; it may cause mild side effects such as [19]:

  • Nausea
  • Gas
  • Skin rash
  • Diarrhea
  • Stomach pain

Many studies have reported no side effects at all [19].

Colostrinin, a proline-rich polypeptide mixture taken from colostrum, can have mild and brief side effects such as anxiety, insomnia, and fatigue [27, 28].

Due to the lack of safety data, pregnant women should avoid taking colostrum supplements.

Colostrum is generally considered safe, though it may cause digestive upset, and pregnant women are advised to avoid it.

Drug Interactions

Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let them know about all drugs and supplements you are using or considering.

Colostrum contains lactoferrin, which may, in theory, bind to NSAIDs and may reduce their effectiveness [21].

Colostrum Supplements & Dosage

Unlike medical hyperimmune colostrum, other supplements have not been approved by the FDA for medical use. In general, regulatory bodies aren’t assuring the quality, safety, and efficacy of supplements. Speak with your doctor before supplementing.

Pills and powders are the most common forms of colostrum. Alternative forms include liquids, sprays, or chewable tablets. Powders were more commonly used in newborns, while pills were used for immune effects in adults.

Manufacturing processes that expose colostrum to high heat may destroy important components. According to the quality regulations, all colostrum supplements should be produced under a cold process. With this in mind, give preference to reliable supplement brands that comply with good manufacturing practices (GMP).

For pets, chewable tablets and powders are available. The powder can be mixed with pet food.

Since adults have fully formed digestive systems that can break down components of colostrum, bioavailability may be an issue. Besides IGF-1, however, other beneficial components can be absorbed well. Some brands have coated formulations that may help bypass breakdown in the gut and increase bioavailability [29].

Colostrum is most broadly available as a pill or powder. Supplements are also available specifically for pets.

Bovine vs. Goat Colostrum

Bovine (cow) colostrum is the most popular type. The vast majority of research was done on it, while very few studies looked at goat colostrum. Due to the lack of research, caution should be taken with goat colostrum, as it may have the same health benefits and side effects.

However, reviews on the web are very positive for goat colostrum. Many users claim that it offers similar benefits as bovine colostrum and some even prefer it.


The below doses may not apply to you personally. If your doctor suggests using colostrum, work with them to find the optimal dosage according to your health condition and other factors.

The dosage can vary depending on what your health concerns are and the benefits you’re seeking. In the published studies, the following doses were used:

  • 60 g/day of concentrated bovine colostrum protein for 8 weeks for upper respiratory tract infection [30].
  • 10 g/ day of concentrated bovine colostrum protein for 5 weeks for reducing post-exercise immune suppression [31].
  • 500 mg 2X/day of bovine colostrum for 20 days for leaky gut [32+].
  • 20 g/day of bovine colostrum powder for 8 weeks to increase lean body mass (along with resistance training) [33].
  • 20 – 60 g/day of the powder for 8 weeks for enhancing athletic performance [34, 35].
  • 10g/day (split into two 5g doses) for 4 weeks for lowering blood sugar in people with type 2 diabetes [36].

Note that the above dosing refers only to regular bovine colostrum or colostrum protein powder. Hyperimmune colostrum is not available as a supplement and was used in clinical studies in lower doses for specific conditions.

User Reviews & Experiences

The opinions expressed in this section are solely from the users who may or may not have a medical background. SelfDecode does not endorse any specific product, service, or treatment. Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice because of something you have read on SelfDecode.

There are many colostrum reviews on the web, mostly positive.

Many users have said that it helps with bladder inflammation (Interstitial Cystitis). One person stated that it resolved their sinus infection whereas antibiotics had no effect. Another person mentioned that it boosted their immune system and helped fight off the flu within a few days.

Some stated that it helped with muscle building.

Many people also use it for leaky gut, finding it very effective and reducing bowel problems and gut permeability.

However, a number of people also had negative experiences. One person said that they took colostrum for a few months but did not notice any change in their immune function. Another had to stop taking it because it caused stomach pain. One person got intense diarrhea after taking it for a few days. Some complained of allergic reactions, which can be expected, especially in those with dairy/lactose intolerance.

Further Reading


Colostrum is extremely important for healthy immune development in newborns, while adults use it for immune support, leaky gut, and exercise performance. Supplements need to be properly processed to maintain their beneficial compounds. If you plan to supplement, select a high-quality product from a trusted manufacturer.

Pregnant women are advised to avoid colostrum supplements, while others should consult with their doctor before taking them.

About the Author

Aleksa Ristic

Aleksa Ristic

MS (Pharmacy)
Aleksa received his MS in Pharmacy from the University of Belgrade, his master thesis focusing on protein sources in plant-based diets.  
Aleksa is passionate about herbal pharmacy, nutrition, and functional medicine. He found a way to merge his two biggest passions—writing and health—and use them for noble purposes. His mission is to bridge the gap between science and everyday life, helping readers improve their health and feel better.


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