Bone broth has not been tested directly in a randomized clinical trial for diabetes or blood sugar control, so there is no straightforward “yes, it works” answer. What researchers have studied are several of its individual components, particularly the amino acid glycine and collagen-derived peptides, and those studies do show measurable effects on insulin sensitivity, fasting glucose, and inflammatory markers tied to type 2 diabetes. The gap between “these ingredients help in studies” and “a mug of bone broth manages your blood sugar” is real, but the evidence is more interesting than you might expect.
What Bone Broth Contains That Matters for Blood Sugar
Bone broth is essentially water that has been simmered with animal bones, connective tissue, and sometimes cartilage for hours. The long cook time draws out collagen, which breaks down into gelatin and then further into individual amino acids. The amino acids present in the highest concentrations are glycine, proline, hydroxyproline, and glutamic acid. Glycine alone can account for roughly a third of the amino acids in collagen, which makes bone broth one of the richest dietary sources of it.
Beyond amino acids, bone broth delivers some minerals. Adding an acid like vinegar during cooking dramatically increases calcium and magnesium extraction from the bones. One study found that dropping the broth’s pH from about 8.4 to about 5.3 boosted calcium extraction more than 17-fold and magnesium extraction more than 15-fold.1PubMed Central. Essential and toxic metals in animal bone broths So how you make the broth changes what you get out of it. Even so, most nutritional analyses suggest bone broth is not a powerhouse of vitamins or minerals. Its potential metabolic value comes primarily from the protein fraction, not the micronutrients.
Glycine and Insulin Sensitivity
Glycine is the amino acid that has attracted the most research attention in the context of blood sugar. People with type 2 diabetes tend to have lower circulating glycine levels than people without the disease, and that association has held up across multiple observational studies. The question is whether supplementing glycine actually changes anything.
In animal research, the answer looks promising. In rats fed a high-sugar diet that made them insulin resistant, glycine treatment improved insulin sensitivity by reducing oxidative stress in the liver and restoring levels of glutathione, the body’s main internal antioxidant. The glycine also improved how insulin receptors functioned at a molecular level, making cells more responsive to insulin signaling.2PubMed Central. Glycine Increases Insulin Sensitivity and Glutathione Biosynthesis and Protects against Oxidative Stress in a Model of Sucrose-Induced Insulin Resistance This matters because insulin resistance is the core problem in type 2 diabetes: the hormone is present, but cells stop responding to it properly.
Glycine also appears to calm chronic low-grade inflammation, another driver of insulin resistance. In fat cells from obese mice, glycine reduced levels of TNF-alpha and IL-6 (two inflammatory signaling molecules linked to metabolic dysfunction) while increasing adiponectin, a hormone that improves insulin sensitivity.3PubMed. Glycine regulates inflammatory markers modifying the energetic balance through PPAR and UCP-2 Cell culture experiments confirmed the same pattern: glycine turned down the expression of pro-inflammatory genes and turned up adiponectin.4PubMed. Glycine increases mRNA adiponectin and diminishes pro-inflammatory adipokines expression in 3T3-L1 cells
The catch is that these are animal and cell studies, not human trials of bone broth. You would also need to drink a fair amount of broth to get the glycine doses used in research, which typically range from 3 to 15 grams per day in human supplement studies. A cup of homemade bone broth might deliver 1 to 3 grams of glycine depending on preparation, so it is a meaningful dietary source but probably not equivalent to a supplement dose on its own.
Collagen Peptides and Human Blood Sugar Data
The closest thing to direct evidence comes from studies on marine collagen peptides given to people with type 2 diabetes. These peptides are essentially what you get when collagen is broken down further than gelatin into small, easily absorbed fragments. They are not identical to sipping bone broth, but they share the same amino acid building blocks.
In a study of Chinese patients with type 2 diabetes, treatment with marine collagen peptides for up to three months led to reduced fasting blood glucose, lower HbA1c (the marker that reflects average blood sugar over two to three months), decreased triglycerides and LDL cholesterol, and improved insulin sensitivity scores.5PubMed. Treatment with marine collagen peptides modulates glucose and lipid metabolism in Chinese patients with type 2 diabetes mellitus A related study in patients who had both type 2 diabetes and high blood pressure found similar results: fasting glucose and HbA1c both dropped compared to controls, while insulin sensitivity and insulin secretion improved.6The American Journal of the Medical Sciences. Therapeutic Effects of Marine Collagen Peptides on Chinese Patients With Type 2 Diabetes Mellitus and Primary Hypertension
These are real, measured improvements in actual patients, which makes them more convincing than animal data alone. But a few caveats are worth noting. The collagen peptides were given at standardized doses in concentrated form, not as a cup of broth. The studies were conducted in a specific population (Chinese adults), and neither was a large multi-center trial. The direction of the findings is encouraging, but the research is still thin enough that no medical guideline recommends collagen peptides as a diabetes treatment.
The Pre-Meal Broth Strategy
One of the more practical angles on bone broth and blood sugar does not depend on any special compound in the broth at all. It depends on protein timing. Research has shown that consuming a small amount of protein before a carbohydrate-heavy meal slows stomach emptying and triggers the release of gut hormones that help manage the glucose spike that follows.
A study in people with diet-controlled type 2 diabetes found that drinking a whey protein preload before a carbohydrate meal led to a marked reduction in the post-meal blood sugar curve. The protein stimulated insulin and incretin hormone secretion while slowing how quickly the food moved through the stomach.7PubMed Central. Effects of a protein preload on gastric emptying, glycemia, and gut hormones after a carbohydrate meal in diet-controlled type 2 diabetes The study used whey protein, not bone broth, but the mechanism is about protein in general slowing digestion and cueing hormonal responses. Bone broth, which contains roughly 6 to 10 grams of protein per cup, could serve a similar function as a pre-meal starter.
This is where the practical case for bone broth gets more interesting. Even if the glycine and collagen benefits are modest at the doses you get from a cup of broth, the simple act of drinking a warm, protein-containing liquid before a meal could blunt the blood sugar spike from whatever you eat next. For someone managing type 2 diabetes through diet, that is a low-risk strategy worth trying.
Gut Integrity and the Inflammation Connection
Chronic low-grade inflammation and a compromised intestinal barrier often go hand in hand with type 2 diabetes. The gut lining is supposed to be selectively permeable, letting nutrients through while keeping bacterial toxins out. In metabolic disorders like obesity and type 2 diabetes, the balance of gut microbes shifts. Beneficial bacteria that produce short-chain fatty acids and protective metabolites decline, while bacteria that produce pro-inflammatory compounds like lipopolysaccharide (LPS) increase. These shifts damage the tight junction proteins that hold the intestinal lining together, allowing inflammatory molecules to leak into the bloodstream.8Current Obesity Reports. A Cascade of Microbiota-Leaky Gut-Inflammation- Is it a Key Player in Metabolic Disorders?
Bone broth advocates often claim it “heals the gut,” and while that language overpromises, there is a kernel of plausibility. Gelatin and the amino acids glutamine and glycine are all involved in maintaining the gut lining. Glutamine, for instance, is a primary fuel source for the cells that line the intestine. Glycine plays a role in bile acid conjugation, which affects fat absorption and microbial balance. Whether drinking bone broth delivers enough of these amino acids to meaningfully repair intestinal barrier function in a person with diabetes has not been tested. The idea is biologically coherent, but clinically unproven.
The Bone Extract Animal Studies
A handful of researchers have tested actual bone extracts in diabetic animals. In one study, rats with induced type 2 diabetes were given extracts prepared from the femur bones of cattle, chickens, sheep, and goats. The animals showed improved metabolic profiles: lower blood lipids, lower liver enzyme markers, reduced inflammatory cytokines (IL-6, TNF-alpha), and restored levels of the antioxidant glutathione and HDL cholesterol. Among the four animal sources, the bovine extract performed best, followed by sheep, goat, and chicken.9PubMed Central. Nutritional Composition and Anti-Type 2 Diabetes Mellitus Potential of Femur Bone Extracts from Bovine, Chicken, Sheep, and Goat: Phytochemical and In Vivo Studies
The fact that the extracts improved multiple diabetes-related markers in rats is noteworthy, but animal models of diabetes do not always predict what happens in people. And the extracts used in research are standardized preparations, not the variable product you get from simmering bones in your kitchen. Still, these studies add weight to the idea that something in the overall matrix of bone-derived compounds has metabolic relevance beyond any single amino acid.
A Real Concern About Advanced Glycation End Products
Here is where the story gets complicated. Bone broth is cooked at moderate heat for a very long time, sometimes 24 hours or more. Prolonged heating of protein-rich, fatty foods generates advanced glycation end products, commonly called AGEs. These are compounds formed when proteins or fats react with sugars under heat, and they promote oxidative stress and inflammation in the body. That is precisely the kind of stress that worsens insulin resistance and diabetes complications.
Research on dietary AGEs has found that cooking with dry heat can increase AGE content by 10-fold to 100-fold compared to the uncooked food. Animal-derived foods high in protein and fat are especially prone to AGE formation. The good news is that cooking with moist heat (as in simmering a broth), at lower temperatures, for shorter durations, and with acidic ingredients like vinegar or lemon juice can significantly reduce AGE formation.10PubMed Central. Advanced glycation end products in foods and a practical guide to their reduction in the diet
Bone broth has a few things going for it here: it is a moist-heat method, and many recipes call for adding vinegar. But the extremely long cook times work against you. Nobody has measured AGE levels in a typical 24-hour bone broth versus a shorter simmer, so the actual tradeoff is unknown. If you are making bone broth specifically for metabolic benefits, keeping cook times moderate (four to eight hours rather than a full day) and including an acid may help you get the amino acids you want while limiting AGE formation.
Lead Contamination Is Not a Myth
Bones accumulate heavy metals over an animal’s lifetime, and lead is the main one that matters for bone broth. A controlled study tested organic chicken bone broth and found that the broth contained several times the lead concentration of the water used to make it. Broth made from skin and cartilage after the chicken had been cooked on the bone had a lead level of about 9.5 micrograms per liter, and pure bone broth came in at about 7 micrograms per liter, compared to under 1 microgram per liter for tap water processed the same way.11PubMed. The risk of lead contamination in bone broth diets
To put this in context, those concentrations are well below the EPA’s action level for lead in drinking water (15 micrograms per liter), so occasional bone broth consumption is unlikely to cause lead toxicity. But for someone drinking bone broth daily as a health practice, the cumulative exposure adds up. People with diabetes already face higher cardiovascular risk, and chronic low-level lead exposure has been linked to vascular damage. If you are using bone broth regularly, sourcing bones from pasture-raised animals (which tend to have lower lead exposure than conventionally raised ones) and varying your sources are reasonable precautions.
Vascular Benefits Worth Knowing About
Type 2 diabetes does most of its damage through blood vessel disease: heart attacks, strokes, kidney failure, and nerve damage all trace back to damaged arteries and impaired circulation. This is where collagen-derived peptides show up in an unexpected way. In rats with experimentally induced hypertension, hydrolyzed collagen from salmon skin lowered blood pressure, reduced oxidative stress and inflammatory markers, and improved the ability of blood vessels to relax in response to signals.12PubMed Central. Hydrolyzed Collagen from Salmon Skin Mitigates L-NAME-Induced Hypertension in Rats by Attenuating Oxidative Stress and Inflammation and Improving Vascular Remodeling
Separate research identified a specific small peptide derived from collagen digestion that, once absorbed intact through the intestinal wall, directly stimulated nitric oxide production in vascular cells.13Journal of Agricultural and Food Chemistry. The Bioavailable Octapeptide Gly-Ala-Hyp-Gly-Leu-Hyp-Gly-Pro Stimulates Nitric Oxide Synthesis in Vascular Endothelial Cells Nitric oxide is the molecule that tells blood vessels to widen, improving blood flow and lowering pressure. For someone with diabetes, whose blood vessels are under constant metabolic assault, anything that supports nitric oxide production is heading in the right direction.
Again, these are animal and cell studies, not human cardiovascular outcome trials. But they point to a broader picture in which collagen-derived peptides interact with the body in ways that go well beyond skin and joint health. The vascular angle is especially relevant for people with diabetes, where blood vessel dysfunction is the main long-term threat.
Practical Considerations for People With Diabetes
If you have type 2 diabetes and want to incorporate bone broth, a few practical points are worth keeping in mind:
- Timing matters: Drinking a cup of broth 15 to 30 minutes before a meal may help blunt the post-meal glucose spike, thanks to the protein preload effect on stomach emptying and incretin hormones.
- Add vinegar: A splash of apple cider vinegar or lemon juice during cooking increases mineral extraction and may limit AGE formation. It also mildly acidifies the broth, which some research suggests could independently help with post-meal blood sugar.
- Watch your sodium: Commercial bone broths can contain 400 to 600 milligrams of sodium per cup, which is a concern if you are also managing blood pressure. Look for low-sodium versions or make your own and add salt to taste.
- Keep cook times reasonable: Four to eight hours extracts most of the collagen and minerals without the extreme duration that raises AGE concerns.
- Do not treat it as medicine: Nothing in the evidence suggests bone broth can replace diabetes medications, metformin, or any other prescribed treatment. The most honest framing is that it is a nutrient-dense food with some metabolic upside that fits well into a blood-sugar-conscious eating pattern.
Store-Bought Versus Homemade
Commercial bone broths vary enormously in protein content, which is the main factor that determines their metabolic relevance. Some shelf-stable products contain as little as 2 grams of protein per cup, which is barely more than flavored water. Others, especially those marketed as “bone broth” rather than “stock” or “broth,” contain 8 to 10 grams per cup. If you are buying rather than making, check the protein content on the nutrition label rather than trusting the packaging language.
Homemade broth gives you control over ingredients, cook time, and acidity, but introduces more variability. A batch made from knuckle and joint bones (rich in cartilage) will have more collagen than one made from marrow bones. Whether you roast the bones first matters for flavor but also increases AGE formation. And as noted, the lead content is hard to control without knowing your source animal’s exposure history.
For people who find bone broth convenient and enjoyable, a reasonable approach is to use it as a regular part of meals rather than a supplement, pairing it with vegetables and whole grains rather than relying on it as a standalone treatment for anything. The glycine and collagen research is encouraging enough to justify including it, and the protein preload data gives it a practical role in glucose management that does not depend on any speculative mechanism.