Does Organic Milk Still Have Hormones in It?

December 19, 2025 •

3 min read

According to a 2019 Emory University study, conventional milk samples had significantly higher levels of growth hormones and pesticide residues than organic samples. This disparity raises a critical question for many consumers: does organic milk still have hormones in it?

Quick Summary

This article explains that while organic milk does not contain added synthetic hormones like rBST, it naturally contains small, harmless amounts of hormones produced by cows. It compares the hormone content of organic and conventional milk and discusses the safety and regulations governing dairy production.

Key Points

Natural vs. Synthetic Hormones: All milk contains natural hormones like bST, but organic milk is free of synthetic growth hormones like rBST due to strict USDA standards.
rBST Prohibited in Organic: The use of recombinant bovine somatotropin (rBST), a synthetic hormone for increasing milk yield, is explicitly banned in organic dairy farming.
Digestion Deactivates Hormones: The trace amounts of natural hormones found in all milk are protein-based and are broken down into harmless amino acids during human digestion.
Higher Growth Hormones in Conventional: Studies have found significantly higher levels of growth hormones in conventional milk compared to organic milk, likely related to the use of synthetic rBST in some conventional farms.
Organic Certification Provides Guarantees: The organic label assures consumers that the product was produced without synthetic hormones and with limited pesticide exposure, appealing to those with food safety concerns.
Individual Choice: Both organic and conventional milk are considered safe by regulatory agencies, and the decision to choose organic is a personal one based on priorities like animal welfare, environmental impact, and personal beliefs.

The Difference Between Natural and Synthetic Hormones

To understand the hormone content of organic milk, it's essential to distinguish between naturally occurring hormones and synthetic ones added during production. All animal products, including milk, naturally contain hormones as part of the animal's biological system.

Natural Bovine Hormones

Cows naturally produce a variety of hormones that are present in their milk. The most relevant one is bovine somatotropin (bST), a protein hormone that regulates normal growth and milk production. While bST is naturally found in all cow's milk, its concentration is very low and it is not biologically active in humans. During digestion, these natural protein hormones are broken down into inactive amino acids, just like any other protein.

Synthetic Hormones (rBST)

Recombinant bovine somatotropin (rBST) is a synthetic version of bST that some conventional dairy farmers use to increase milk production. The use of rBST is a significant point of difference between conventional and organic milk production. USDA organic standards strictly prohibit the use of this synthetic hormone. While the FDA has deemed milk from rBST-treated cows safe, many consumers prefer to avoid it.

Comparison of Organic vs. Conventional Milk Hormone Content

While both organic and conventional milk naturally contain trace amounts of hormones, studies have shown significant differences in levels of synthetic growth hormones and related compounds. An Emory University study found conventional milk samples had twenty times higher levels of growth hormones than organic milk.

Comparison of Hormone-Related Factors


Feature	Organic Milk	Conventional Milk (Standard)
Synthetic rBST	Not permitted	Historically permitted; many dairies now voluntarily abstain due to consumer demand
Natural bST	Present in trace, natural amounts	Present in trace, natural amounts, but levels of synthetic growth hormones can be elevated due to rBST use
Antibiotics	Prohibited for use; treated cows are removed from the organic herd	Allowed; milk is tested to ensure it is free of residues before reaching consumers
Pesticide Residues	Minimal to none; produced on land free of synthetic pesticides for years	Potential for residues from conventional farming practices
Dietary Intake of Cows	Requires organic, GMO-free feed and often greater access to pasture	May use conventional feed, which could contain pesticide residues

The Role of Natural Hormones in All Milk

It is a misconception that any milk, organic or not, can be completely "hormone-free." As a natural product of a mammal, milk is a biological fluid designed to nourish offspring, and hormones are an inherent component of that process. These natural hormones, such as bST and Insulin-like Growth Factor 1 (IGF-1), are present in minute quantities and are largely deactivated during digestion in humans.

How Pregnancy Affects Hormone Levels

Hormone levels can vary in milk depending on the cow's reproductive cycle. Milk from pregnant cows, which is more common in modern dairy farming, contains higher levels of naturally occurring estrogens. While this is true for both conventional and organic milk, studies suggest the amount of estrogen from milk is minimal compared to the body's own production and does not significantly impact human hormone balance.

Organic Production Standards and Consumer Choice

The USDA's National Organic Program (NOP) sets strict standards that regulate organic dairy production. These rules forbid synthetic growth hormones and require specific animal welfare and feeding practices. The organic label thus provides a guarantee against synthetic rBST and certain pesticides, which many consumers prioritize when making food choices. However, whether the higher cost of organic milk is justified depends on individual consumer priorities regarding food safety, environmental impact, and animal welfare, as both conventional and organic milk are deemed safe by regulatory bodies.

Conclusion

Ultimately, the question of "Does organic milk still have hormones in it?" can be answered with a clear "yes," but with an important clarification. All milk, whether organic or conventional, contains naturally occurring, trace amounts of hormones. However, organic milk is certified free of the synthetic growth hormone rBST, which is sometimes used in conventional dairy farming. For consumers who prioritize avoiding synthetic additives and certain pesticide residues, organic milk provides a clear choice based on regulated production standards. It's an issue of preference and farming practice, rather than an absolute absence of hormones.

For more information on the safety of milk from rBST-supplemented cows, you can consult the official position of the U.S. Food and Drug Administration.

Frequently Asked Questions

No, it is impossible for milk to be entirely hormone-free. As a product of a lactating mammal, milk naturally contains very small amounts of hormones. The term "hormone-free" is often used to refer to the absence of synthetic hormones, not natural ones.

rBST (recombinant bovine somatotropin) is a synthetic growth hormone used by some conventional dairy farmers to increase milk production. It is not in organic milk because USDA organic regulations prohibit its use.

According to the FDA and other health organizations, the hormones naturally present in milk are digested and become inactive in the human body. The levels are so low they are not considered a human health concern for most people.

Yes. Organic milk, like all milk from mammals, contains natural hormones produced by the cow. These include bovine somatotropin (bST), but in very small quantities.

Yes. Organic standards also prohibit the use of antibiotics and require cows to have access to organic feed and outdoor grazing. Studies also show organic milk has minimal pesticide residues compared to conventional.

Both organic and conventional milk are regulated and considered safe. For some consumers, the reduced exposure to synthetic growth hormones and pesticides in organic milk is a benefit. The choice often comes down to personal preference and values.

Organic milk is typically more expensive due to higher production costs associated with organic farming. These include the cost of organic feed, stricter animal welfare standards, and generally lower milk yields per cow.