Bone broth is a rich, savory liquid made by simmering animal bones for an extended period, typically anywhere from 8 to 72 hours. The long cooking time draws out collagen, amino acids, and small amounts of minerals, producing a thick, gelatinous broth prized for both cooking and drinking on its own. Despite the trendy reputation and premium price tags, bone broth is essentially a traditional stock by another name, with roots in kitchens around the world long before it became a wellness staple.
Bone Broth vs. Broth vs. Stock
Regular broth is the lightest of the three. It’s made by simmering meat and vegetables for a short time, producing a thin, mildly flavored liquid. Stock goes a step further: bones are simmered along with herbs, spices, and vegetables for longer, and the result is noticeably thicker because gelatin and collagen leach out of the bones during cooking.
Bone broth is, functionally, the same thing as stock. The main distinction some cooks make is time. Bone broth is often simmered for many hours longer than a typical stock to extract even more collagen and flavor. The result is a liquid that firms up into a jiggly gel when refrigerated, a sign of high gelatin content.
What’s Actually in It
Bone broth’s nutritional appeal comes primarily from its amino acid content, not its minerals. The three most abundant amino acids are glycine, proline, and hydroxyproline, all building blocks of collagen. Chicken bone broth tends to have slightly higher concentrations than beef or turkey: roughly 4 mg of glycine, 2.4 mg of proline, and 2.2 mg of hydroxyproline per gram of broth. A full cup delivers meaningful amounts of these amino acids, which play roles in connective tissue maintenance, skin structure, and gut lining repair.
Where bone broth falls short is minerals. Despite a widespread belief that it’s a good source of calcium and magnesium, lab analyses tell a different story. The calcium and magnesium in a typical serving amount to no more than low tenths of a milligram, supplying less than 5% of your daily recommended intake. Even cooking bones longer than 8 hours or adding acid to the pot improves extraction only modestly in absolute terms. Bone broth is not a reliable substitute for dairy, leafy greens, or other mineral-rich foods.
Collagen and Joint Health
Collagen is the most abundant protein in your body, forming the structural framework of cartilage, tendons, ligaments, and skin. When you drink bone broth, the collagen has already been partially broken down by heat into gelatin. Your digestive system breaks it down further into individual amino acids and small peptide chains, some of which have been shown to accumulate in cartilage tissue after absorption.
Research on collagen supplements suggests two distinct mechanisms at work. Hydrolyzed collagen (the broken-down form) may contain biologically active peptides that reach joint tissues and help protect cartilage cells. Undenatured collagen, which retains more of its original structure, appears to work through the immune system by calming inflammatory responses in the joints. Bone broth delivers collagen mostly in the gelatin form, which falls somewhere between these two. The evidence for purified collagen supplements and joint health is stronger than the evidence for bone broth specifically, but the underlying amino acids are the same.
Gut Lining Support
One of bone broth’s most popular claims is that it “heals the gut,” and while that overstates the evidence, the amino acids in bone broth do have documented effects on intestinal cells. Glutamine, an amino acid present in bone broth, is the primary fuel source for the cells lining your small intestine. It stimulates those cells to grow and divide, and it enhances the effects of growth factors that help the intestinal lining renew itself.
Glutamine also helps maintain the tight junctions between intestinal cells. These junctions act like seals that control what passes through the gut wall into the bloodstream. When glutamine is depleted, the proteins that form these seals decrease significantly, and barrier function breaks down. Restoring glutamine rescues this impaired function. On top of that, glutamine suppresses inflammatory signaling pathways in intestinal tissue and supports the production of glutathione, a powerful antioxidant that protects gut cells from damage. Glycine, the most abundant amino acid in bone broth, contributes to glutathione production as well.
These mechanisms are well-established in cell and animal studies. Clinical trials using bone broth itself are limited, so the leap from “glutamine supports gut cells in a lab” to “drinking bone broth heals a leaky gut” remains partly speculative.
Skin, Hair, and Collagen
Oral collagen supplementation does appear to benefit skin. A randomized, placebo-controlled study of 72 women found that taking 2.5 grams of collagen peptides daily for 12 weeks increased skin hydration by 28% (compared to 9% in the placebo group), reduced wrinkle depth by about 27%, and boosted skin density by nearly 25%. A broader review of 11 studies covering 805 participants confirmed that collagen peptides can improve skin hydration, elasticity, and collagen density.
These studies used concentrated collagen supplements, not bone broth. A cup of bone broth contains collagen, but the exact amount varies widely depending on the bones used, cooking time, and preparation method. You’d likely need to drink bone broth consistently and in significant quantities to approach the doses used in clinical trials. Still, the amino acid profile of bone broth, rich in glycine, proline, and hydroxyproline, provides the same raw materials your body uses to build collagen.
The Lead Concern
Bones store lead and other heavy metals absorbed over an animal’s lifetime, and long simmering can draw some of that lead into the broth. A controlled study of organic chicken bone broth found lead concentrations of 7.01 micrograms per liter in bone broth and 9.5 micrograms per liter in broth made from skin and cartilage. For comparison, the tap water used in the same study contained just 0.89 micrograms per liter.
These levels are still relatively low in absolute terms and well below the thresholds that cause acute harm. But lead accumulates in the body over time, and there is no level of lead exposure considered completely safe. If you drink bone broth occasionally, this is unlikely to be a concern. If you’re consuming it daily as a health practice, or giving it regularly to young children, it’s worth knowing that the lead content is measurably higher than plain water.
How to Make It
The basic process is simple: place bones in a large pot, cover with water, add a splash of acid, and simmer for a long time. Adding one to two tablespoons of apple cider vinegar or another acid before cooking helps break down the bone matrix and extract slightly more minerals and collagen. Vegetables like onions, carrots, and celery add flavor but are optional.
Cooking times vary by bone type. Poultry bones need a minimum of 8 hours to release substantial gelatin, with 24 to 48 hours yielding more. Beef bones, which are denser, benefit from at least 12 hours and can go as long as 48 to 72 hours. You’ll know you’ve extracted enough collagen when the cooled broth sets into a firm gel in the refrigerator. A slow cooker or pressure cooker works as well as the stovetop, with pressure cookers cutting the time significantly.
Roasting bones at high heat before simmering deepens the flavor and color. Skimming the foam that rises during the first hour of cooking produces a clearer broth. Once finished, strain out the solids and store the broth in the refrigerator for up to five days or freeze it for several months.